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Sample records for rat colon loops

  1. In Situ Perfusion Model in Rat Colon for Drug Absorption Studies: Comparison with Small Intestine and Caco-2 Cell Model.

    PubMed

    Lozoya-Agullo, Isabel; González-Álvarez, Isabel; González-Álvarez, Marta; Merino-Sanjuán, Matilde; Bermejo, Marival

    2015-09-01

    Our aim is to develop and to validate the in situ closed loop perfusion method in rat colon and to compare with small intestine and Caco-2 cell models. Correlations with human oral fraction absorbed (Fa) and human colon fraction absorbed (Fa_colon) were developed to check the applicability of the rat colon model for controlled release (CR) drug screening. Sixteen model drugs were selected and their permeabilities assessed in rat small intestine and colon, and in Caco-2 monolayers. Correlations between colon/intestine/Caco-2 permeabilities versus human Fa and human Fa_colon have been explored to check model predictability and to apply a BCS approach in order to propose a cut off value for CR screening. Rat intestine perfusion with Doluisio's method and single-pass technique provided a similar range of permeabilities demonstrating the possibility of combining data from different laboratories. Rat colon permeability was well correlated with Caco-2 cell-4 days model reflecting a higher paracellular permeability. Rat colon permeabilities were also higher than human colon ones. In spite of the magnitude differences, a good sigmoidal relationship has been shown between rat colon permeabilities and human colon fractions absorbed, indicating that rat colon perfusion can be used for compound classification and screening of CR candidates. PMID:25891783

  2. Colonic Fermentation Promotes Decompression sickness in Rats.

    PubMed

    de Maistre, Sébastien; Vallée, Nicolas; Gempp, Emmanuel; Lambrechts, Kate; Louge, Pierre; Duchamp, Claude; Blatteau, Jean-Eric

    2016-01-01

    Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body's H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production. PMID:26853722

  3. Colonic Fermentation Promotes Decompression sickness in Rats

    PubMed Central

    de Maistre, Sébastien; Vallée, Nicolas; Gempp, Emmanuel; Lambrechts, Kate; Louge, Pierre; Duchamp, Claude; Blatteau, Jean-Eric

    2016-01-01

    Massive bubble formation after diving can lead to decompression sickness (DCS). During dives with hydrogen as a diluent for oxygen, decreasing the body’s H2 burden by inoculating hydrogen-metabolizing microbes into the gut reduces the risk of DCS. So we set out to investigate if colonic fermentation leading to endogenous hydrogen production promotes DCS in fasting rats. Four hours before an experimental dive, 93 fasting rats were force-fed, half of them with mannitol and the other half with water. Exhaled hydrogen was measured before and after force-feeding. Following the hyperbaric exposure, we looked for signs of DCS. A higher incidence of DCS was found in rats force-fed with mannitol than in those force-fed with water (80%, [95%CI 56, 94] versus 40%, [95%CI 19, 64], p < 0.01). In rats force-fed with mannitol, metronidazole pretreatment reduced the incidence of DCS (33%, [95%CI 15, 57], p = 0.005) at the same time as it inhibited colonic fermentation (14 ± 35 ppm versus 118 ± 90 ppm, p = 0.0001). Pre-diveingestion of mannitol increased the incidence of DCS in fasting rats when colonic fermentation peaked during the decompression phase. More generally, colonic fermentation in rats on a normal diet could promote DCS through endogenous hydrogen production. PMID:26853722

  4. Nuclear microscopy of rat colon epithelial cells

    NASA Astrophysics Data System (ADS)

    Ren, M.; Rajendran, Reshmi; Ng, Mary; Udalagama, Chammika; Rodrigues, Anna E.; Watt, Frank; Jenner, Andrew Michael

    2011-10-01

    Using Nuclear microscopy, we have investigated iron distributions in the colons of Sprague Dawley rats, in order to elucidate heme uptake. Four groups of five Sprague Dawley rats (mean weight 180 g) were fed different purified diets containing either heme diet (2.5% w/w hemoglobin), high fat diet (HFD) (18% w/w fat, 1% w/w cholesterol), 'western' diet (combination of hemoglobin 2.5% and 18% fat, 1% cholesterol) or control diet (7% w/w fat). After 4 weeks, animals were sacrificed by exsanguination after anaesthesia. Thin sections of frozen colon tissue were taken, freeze dried and scanned using nuclear microscopy utilising the techniques PIXE, RBS and STIM. The new data acquisition system (IonDaq) developed in CIBA was used to obtain high resolution images and line scans were used to map the iron distributions across the colon boundaries. The nuclear microscope results indicate that when HFD is given in addition to heme, the iron content of the epithelial cells that line the colon decreases, and the zinc in the smooth muscle wall increases. This implies that the level of heme and fat in diet has an important role in colon health, possibly by influencing epithelial cells directly or changing luminal composition such as bacterial flora or levels of metabolites and cytotoxins.

  5. An unusual colon atresia in a calf: at the junction of the distal loop and transverse colon. A brief overview

    PubMed Central

    Lombardero, Matilde; Yllera, María del Mar

    2014-01-01

    Congenital defects are those abnormalities present at birth. During embryogenesis, many anomalies can occur. The primitive gut tube lengthens quickly and rotates, allowing the gastrointestinal tract acquire its final position and orientation. Because the colon of large animals is complex, most changes occur in this segment. Thus, in ruminants, colon atresia is the most frequent malformation, affecting mainly ascending colon, at the level of the spiral loop. There are no previous references about a very atypical colon atresia at the junction of distal loop and transverse colon, such we have described in a 5-day-old calf, after a history of abdominal distention and absence of feces at birth, even with a patent anal opening. Atresia coli was detected at distal position of the typical colon atresia, at the junction of distal loop and transverse colon. In addition, the distal blind end was bent into a U-shape supported by the mesocolon. Besides the anatomical findings of this worthwhile atresia coli we discuss its possible etiology, in which local factors, such as a compromised blood supply during embryogenesis, are more consistent than genetic factors. Finding out the causes of atresia coli would help to reduce its incidence, lessen animal suffering and economic loss. PMID:25495264

  6. Salmonella induces prominent gene expression in the rat colon

    PubMed Central

    Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Roosing, Susanne; Vink, Carolien; Katan, Martijn B; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg MJ

    2007-01-01

    Background Salmonella enteritidis is suggested to translocate in the small intestine. In vivo it induces gene expression changes in the ileal mucosa and Peyer's patches. Stimulation of Salmonella translocation by dietary prebiotics fermented in colon suggests involvement of the colon as well. However, effects of Salmonella on colonic gene expression in vivo are largely unknown. We aimed to characterize time dependent Salmonella-induced changes of colonic mucosal gene expression in rats using whole genome microarrays. For this, rats were orally infected with Salmonella enteritidis to mimic a foodborne infection and colonic gene expression was determined at days 1, 3 and 6 post-infection (n = 8 rats per time-point). As fructo-oligosaccharides (FOS) affect colonic physiology, we analyzed colonic mucosal gene expression of FOS-fed versus cellulose-fed rats infected with Salmonella in a separate experiment. Colonic mucosal samples were isolated at day 2 post-infection. Results Salmonella affected transport (e.g. Chloride channel calcium activated 6, H+/K+ transporting Atp-ase), antimicrobial defense (e.g. Lipopolysaccharide binding protein, Defensin 5 and phospholipase A2), inflammation (e.g. calprotectin), oxidative stress related genes (e.g. Dual oxidase 2 and Glutathione peroxidase 2) and Proteolysis (e.g. Ubiquitin D and Proteosome subunit beta type 9). Furthermore, Salmonella translocation increased serum IFNγ and many interferon-related genes in colonic mucosa. The gene most strongly induced by Salmonella infection was Pancreatitis Associated Protein (Pap), showing >100-fold induction at day 6 after oral infection. Results were confirmed by Q-PCR in individual rats. Stimulation of Salmonella translocation by dietary FOS was accompanied by enhancement of the Salmonella-induced mucosal processes, not by induction of other processes. Conclusion We conclude that the colon is a target tissue for Salmonella, considering the abundant changes in mucosal gene expression

  7. Triptolide ameliorates colonic fibrosis in an experimental rat model

    PubMed Central

    TAO, QINGSONG; WANG, BAOCHAI; ZHENG, YU; LI, GUANWEI; REN, JIANAN

    2015-01-01

    Triptolide is known to exert anti-inflammatory and immunomodulatory activities; however, its impact on intestinal fibrosis has not been previously examined. Based on our previous studies of the suppressive activity of triptolide on human colonic subepithelial myofibroblasts and the therapeutic efficacy of triptolide in Crohn’s disease, it was hypothesized that triptolide may have beneficial effects on intestinal fibrosis. In the present study, colonic fibrosis was induced in rats by 6 weekly repeated administration with a low-dose of 2,4,6-trinitrobenzene sulfonic acid (TNBS) and was then treated with triptolide or PBS daily (control) simultaneously. Extracellular matrix (ECM) deposition in the colon was examined with image analysis of Masson Trichrome staining. Total collagen levels in colonic homogenates were measured by a Sircol assay. Collagen Iα1 transcripts and collagen I protein were measured ex vivo in the isolated colonic subepithelial myofibroblasts by reverse transcription-quantitative polymerase chain reaction and immunoblot analysis, respectively. The results indicated that triptolide decreased ECM deposition and collagen production in the colon, and inhibited collagen Iα1 transcripts and collagen I protein expression in the isolated subepithelial myofibroblasts of the rats with colonic fibrosis. In conclusion, triptolide ameliorates colonic fibrosis in the experimental rat model, suggesting triptolide may be a promising compound for inflammatory bowel disease treatment. PMID:25845760

  8. Effects of Bowman-Birk inhibitor on rat colon carcinogenesis.

    PubMed

    Kennedy, Ann R; Billings, Paul C; Wan, X Steven; Newberne, Paul M

    2002-01-01

    The present study was undertaken to determine whether the Bowman-Birk inhibitor (BBI) could prevent colon carcinogenesis in rats treated with dimethylhydrazine (DMH) and whether there were adverse side effects associated with treatment with BBI for cancer prevention. BBI was evaluated in the forms of purified BBI (PBBI) or an extract of soybeans enriched in BBI, termed BBI concentrate (BBIC). The results demonstrate that PBBI and BBIC reduced the incidence and frequency of tumors in DMH-treated rats compared with animals treated with DMH alone. Autoclaved BBIC, in which the protease inhibitor activity of BBI was destroyed, had a weak and statistically insignificant, suppressive effect on DMH-induced colon carcinogenesis in rats, suggesting that the protease inhibitor activity of BBI is likely to be responsible for the anticarcinogenic activity of BBIC. Soy molasses, which contains soy isoflavones, did not have an effect on colon cancer carcinogenesis in DMH-treated rats. Similar to results from previous studies (Nauss et al. JNCI 73, 915-924, 1984), the most aggressive, malignant colon adenocarcinomas developed within or in association with gut-associated lymphoid tissue aggregates. No adverse side effects on the pancreas or animal growth were observed in rats treated with PBBI or BBIC. These results demonstrate that PBBI and BBIC may be used to prevent colon cancer without significant adverse side effects. PMID:12588698

  9. Piroxicam decreases postirradiation colonic neoplasia in the rat

    SciTech Connect

    Northway, M.G.; Scobey, M.W.; Cassidy, K.T.; Geisinger, K.R. )

    1990-12-01

    This study evaluated the effects of the nonsteroidal antiinflammatory agent piroxicam on chronic radiation proctitis in the rat. Forty female Wistar rats received a 2250-cGy dose of irradiation to the distal 2 cm of the colon. Twenty received piroxicam 8.0 mg/kg orally 30 minutes before exposure and 24 hours after exposure; 20 rats served as irradiated controls. All animals were evaluated by colonoscopy 1 and 3 weeks postexposure and every third week until death or killing at 1 year. At killing, colons were removed for light microscopic examination. One year postirradiation results showed no differences in mortality, vascular changes, acute inflammation, colitis cystica profunda, or rectal stricture between the control and piroxicam-treated groups. However, at 1 year postirradiation the control group demonstrated neoplasia in 15 of 19 animals compared with eight of 20 animals in the piroxicam-treated group. The first endoscopic appearance of colonic neoplasm occurred at 15 weeks postirradiation in one control irradiated rat whereas the first evidence of endoscopic neoplasm in the piroxicam-treated group did not occur until 36 weeks postirradiation. Histologic examination documented a tendency toward a greater presence of adenocarcinomas in the control group compared with the piroxicam-treated group. The authors conclude that piroxicam treatment significantly decreased the incidence of colonic neoplasia in general as well as delayed the endoscopic appearance of colonic neoplasia in rats after pelvic irradiation. 41 references.

  10. Alteration of gene expression in rat colon mucosa after exercise.

    PubMed

    Buehlmeyer, K; Doering, F; Daniel, H; Kindermann, B; Schulz, T; Michna, H

    2008-01-01

    The development of colon cancer is highly influenced by lifestyle factors such as nutrition and physical inactivity. Detailed biological mechanisms are thus far unclear. The purpose of this study was to investigate the effects of regular treadmill exercise on gene expression in rat colon mucosa. For this purpose, 6-week-old male Wistar rats completed a stress-free voluntary treadmill exercise period of 12 weeks. Sedentary rats served as a control group. In the colon mucosa, steady-state mRNA expression levels of approximately 10,000 genes were compared between both groups by micro-array analysis (MWG rat 10K array). A total of 8846 mRNAs were detected above background level. Regular exercise led to a decreased expression of 47 genes at a threshold-factor of 2.0. Three genes were found to be up-regulated in the exercise group. The identified genes encode proteins involved in signal transduction (n=11), transport (n=8), immune system (n=7), cytoskeleton (n=6), protein targeting (n=6), metabolism (n=5), transcription (n=3) and vascularization (n=2). Among the genes regulated by regular exercise, the betaine-homocysteine methyltransferase 2 (BHMT2) seems to be of particular interest. Physical activity may protect against aberrant methylation by repressing the BHMT2 gene and thus contribute to a decreased risk of developing colon cancer. We have also identified vascular endothelial growth factor (VEGF), angiopoietin-2 (ANG-2) and calcium-independent phospholipase a2 (iPL-A2), all of them with markedly reduced transcript levels in the mucosa of active rats. In summary, our experiment presents the first gene expression pattern in rat colon mucosa following regular treadmill activity and represents an important step in understanding the molecular mechanisms responsible for the preventive effect of physical activity on the development of colon cancer. PMID:18342145

  11. Hypothalamic circuit regulating colonic transit following chronic stress in rats.

    PubMed

    Yoshimoto, Sazu; Cerjak, Diana; Babygirija, Reji; Bulbul, Mehmet; Ludwig, Kirk; Takahashi, Toku

    2012-03-01

    Although acute stress accelerates colonic transit, the effect of chronic stress on colonic transit remains unclear. In this study, rats received repeated restraint stress (chronic homotypic stress) or various types of stress (chronic heterotypic stress) for 5 and 7 days, respectively. Vehicle saline, oxytocin (OXT), OXT receptor antagonist or corticotropin-releasing factor (CRF) receptor antagonists were administered by intracerebroventricular (ICV) injection prior to restraint stress for 90 min. Immediately after the stress exposure, the entire colon was removed and the geometric center (GC) of Na51CrO4 (a nonabsorbable radioactive marker; 0.5 μCi) distribution was calculated to measure the transit. Gene expression of OXT and CRF in the paraventricular nucleus (PVN) was evaluated by in situ hybridization. Accelerated colonic transit with the acute stressor was no longer observed following chronic homotypic stress. This restored colonic transit was reversed by ICV injection of an OXT antagonist. In contrast, chronic heterotypic stress significantly accelerated colonic transit, which was attenuated by ICV injection of OXT and by a CRF receptor 1 antagonist. OXT mRNA expression in the PVN was significantly increased following chronic homotypic stress, but not chronic heterotypic stress. However, CRF mRNA expression in the PVN was significantly increased following acute and chronic heterotypic stress, but not chronic homotypic stress. These results indicate that central OXT and CRF play a pivotal role in mediating the colonic dysmotility following chronic stress in rats. PMID:21936687

  12. Mucin secretion is modulated by luminal factors in the isolated vascularly perfused rat colon

    PubMed Central

    Barcelo, A; Claustre, J; Moro, F; Chayvialle, J; Cuber, J; Plaisancie, P

    2000-01-01

    BACKGROUND—Mucins play an important protective role in the colonic mucosa. Luminal factors modulating colonic mucus release have been not fully identified.
AIM—To determine the effect of some dietary compounds on mucus discharge in rat colon.
METHODS—An isolated vascularly perfused rat colon model was used. Mucus secretion was induced by a variety of luminal factors administered as a bolus of 1 ml for 30 minutes in the colonic loop. Mucin release was evaluated using a sandwich enzyme linked immunosorbent assay supported by histological analysis.
RESULTS—The three dietary fibres tested in this study (pectin, gum arabic, and cellulose) did not provoke mucus secretion. Luminal administration of sodium alginate (an algal polysaccharide used as a food additive) or ulvan (a sulphated algal polymer) induced a dose dependent increase in mucin discharge over the concentration range 1-25 mg/l (p<0.05 for 25 mg/l alginate and p<0.05 for 10 and 25 mg/l ulvan). Glucuronic acid and galacturonic acid, which are major constituents of a variety of fibres, produced significant mucin secretion (p<0.05). Hydrogen sulphide and mercaptoacetate, two sulphides produced in the colonic lumen by microbial fermentation of sulphated polysaccharides, did not modify mucin secretion. Among the short chain fatty acids, acetate (5-100 mM) induced a dose dependent release of mucus (p<0.05 for 100 mM acetate). Interestingly, butyrate at a concentration of 5 mM produced colonic mucin secretion (p<0.05), but increasing its concentration to 100 mM provoked a gradual decrease in mucus discharge. Propionate (5-100 mM) did not induce mucin release. Several dietary phenolic compounds (quercetin, epicatechin, resveratrol) did not provoke mucus discharge.
CONCLUSIONS—Two algal polysaccharides (alginate and ulvan), two uronic acids (glucuronic acid and galacturonic acid), and the short chain fatty acids acetate and butyrate induce mucin secretion in rat colon. Taken together, these

  13. Cruciferous vegetables and glutathione: their effects on colon mucosal glutathione level and colon tumor development in rats induced by DMH.

    PubMed

    Chen, M F; Chen, L T; Boyce, H W

    1995-01-01

    The effect of a diet containing 10-40% lyophilized cabbage or broccoli as cruciferous vegetable or 10-40% lyophilized potato as noncruciferous vegetable fed for 14 days on the colon mucosal glutathione (GSH) level was studied in male rats. The GSH levels of the duodenum mucosa and the liver were also measured. Cabbage and broccoli enhanced the colon and duodenum mucosal GSH levels in a dose-related manner; potato had no effect. All three vegetables had no effect on the liver GSH level. The effect of GSH on colon tumorigenesis induced by 1,2-dimethylhydrazine (DMH) was also examined in rats. Male Sprague-Dawley rats were injected with DMH (20 mg/kg body wt) weekly for 20 weeks. DMH lowered the colon mucosal GSH level. GSH (100 mg/day/rat) dissolved in the drinking water and given to rats during and after DMH injections had little or no effect on tumor incidence and total number of colon tumors. Tumors were larger in rats that received GSH than in those that received water. This study shows that the colon mucosal GSH level can be enhanced by feeding rats a diet high in cabbage or broccoli and that GSH added to the drinking water did not affect DMH-induced colon tumorigenesis under the experimental conditions used. PMID:7739917

  14. Early colonizing Escherichia coli elicits remodeling of rat colonic epithelium shifting toward a new homeostatic state

    PubMed Central

    Tomas, Julie; Reygner, Julie; Mayeur, Camille; Ducroc, Robert; Bouet, Stephan; Bridonneau, Chantal; Cavin, Jean-Baptiste; Thomas, Muriel; Langella, Philippe; Cherbuy, Claire

    2015-01-01

    We investigated the effects of early colonizing bacteria on the colonic epithelium. We isolated dominant bacteria, Escherichia coli, Enterococcus faecalis, Lactobacillus intestinalis, Clostridium innocuum and a novel Fusobacterium spp., from the intestinal contents of conventional suckling rats and transferred them in different combinations into germfree (GF) adult rats. Animals were investigated after various times up to 21 days. Proliferative cell markers (Ki67, proliferating cell nuclear antigen, phospho-histone H3, cyclin A) were higher in rats monocolonized with E. coli than in GF at all time points, but not in rats monocolonized with E. faecalis. The mucin content of goblet cells declined shortly after E. coli administration whereas the mucus layer doubled in thickness. Fluorescence in situ hybridization analyses revealed that E. coli resides in this mucus layer. The epithelial mucin content progressively returned to baseline, following an increase in KLF4 and in the cell cycle arrest-related proteins p21CIP1 and p27KIP1. Markers of colonic differentiated cells involved in electrolyte (carbonic anhydrase II and slc26A3) and water (aquaglyceroporin3 (aqp3)) transport, and secretory responses to carbachol were modulated after E. coli inoculation suggesting that ion transport dynamics were also affected. The colonic responses to simplified microbiotas differed substantially according to whether or not E. coli was combined with the other four bacteria. Thus, proliferation markers increased substantially when E. coli was in the mix, but very much less when it was absent. This work demonstrates that a pioneer strain of E. coli elicits sequential epithelial remodeling affecting the structure, mucus layer and ionic movements and suggests this can result in a microbiota-compliant state. PMID:25012905

  15. Intraglomerular microcirculation: measurements of single glomerular loop flow in rats.

    PubMed

    Steinhausen, M; Zimmerhackl, B; Thederan, H; Dussel, R; Parekh, N; Esslinger, H U; von Hagens, G; Komitowski, D; Dallenbach, F D

    1981-08-01

    With the use of a new fluorescent microscopic technique, we were able to measure the mean intracapillary velocities and pressures of single capillary loops of renal glomeruli of living rats. The technique involved photographing and recording the flow of fluorescent latex particles through the glomerular loops with a television monitor. In 25 rats the single glomerular loop flow velocity was 781 +/- (SD) 271 micrometers . sec-1. The mean diameter of the capillary loops measured 8.4 +/- 1.4 micrometers; their lengths were 72.3 +/- 37.5 micrometers. From the decrease in velocity of flow along the capillary loop, we were able to evaluate the filtration equivalent for the capillary surface. It was possible to measure intracapillary pressures of single glomerular loops continuously under microscopic control. High intracapillary pressures correlated with high intracapillary velocities. From the data we obtained, we were unable to calculate a filtration equilibrium at the ends of the observed capillary loops. For further correlations, we injected the glomeruli we had studied in the living state and examined them with the scanning electron microscope. PMID:7289407

  16. Plasminogen receptors on rat colon carcinoma cells.

    PubMed Central

    Durliat, M.; Komano, O.; Correc, P.; Bertrand, O.; Cochet, S.; Caignard, A.; Martin, F.; Burtin, P.

    1992-01-01

    Cells from rat carcinoma cell lines PROb (giving progressive tumours) and REGb (giving regressive tumours) have cell surface receptors which bind specifically rat plasminogen and plasmin. Affinity for Pg was found to be higher in PROb (Kd = 10(-7) M) than in REGb cells (Kd = 5.10(-7) M) but with a concomitant decrease in the number of binding sites, 0.9 x 10(6)/cell (range from 0.6 to 1.2 x 10(6)) in PROb vs 3.6 x 10(6)/cell (range 1.2 to 6 x 10(6)) in REGb cells. The number and the affinity of binding sites varied in an opposite way in PROb and REGb cells. The difference in affinity parameters was unrelated to the degree of invasiveness of tumour cells in syngenetic rats. Bound plasmin retained its enzymatic activity, which indicates that its binding does not involve the catalytic active site. In cell solubilisates plasminogen receptor appeared as one major band situated in the area of 50-60 kDa. Images Figure 3 Figure 5 PMID:1322156

  17. Fate of oleate in the colon of the rat

    SciTech Connect

    Segal, L.; Kneip, J.; Levitt, M.D. )

    1990-02-01

    To study the fate of oleate in the colon, oleate labeled with carbon 14 was instilled into the cecum of four rats through chronically implanted cecal cannulas. Fecal recovery of {sup 14}C and {sup 14}CO{sub 2} excretion were measured over a 3-day period. A mean of only 57% +/- 6% of the dose of ({sup 14}C(U))oleate was recovered as {sup 14}C in fecal lipid. About 8% was recovered in the aqueous phase of feces and 4% was recovered as {sup 14}CO{sub 2}. Occlusion of the terminal ileum did not diminish {sup 14}CO{sub 2} excretion, excluding ileal reflux with small bowel absorption. Studies in two germ-free rats showed no conversion of ({sup 14}C(U))oleate to fecal water-soluble compounds, indicating that ({sup 14}C)oleate is converted into water-soluble compounds by bacterial metabolism. The metabolism of ({sup 14}C)oleate to {sup 14}CO{sub 2} was also observed in germ-free rats, indicating oxidation in the colon or other host tissues. We conclude that the colonic absorption of lipid or lipid metabolites plus conversion to water-soluble fecal compounds or volatile metabolites results in a fecal fat measurement that appreciably overestimates small bowel absorption of lipid.

  18. Adherence of Entamoeba histolytica trophozoites to rat and human colonic mucosa.

    PubMed Central

    Ravdin, J I; John, J E; Johnston, L I; Innes, D J; Guerrant, R L

    1985-01-01

    We studied the adherence of [3H]thymidine-labeled axenic Entamoeba histolytica (strain HM1-IMSS) to in vitro preparations of rat and human colonic mucosa. Studies were performed with fixed or unfixed rat colonic mucosa, unfixed rat mucosa exposed to trypsin, unfixed rat submucosa, and fixed human colonic mucosa. Twenty percent of the amebae adhered to fixed rat colonic mucosa; adherence was specifically inhibited by N-acetyl-D-galactosamine (GalNAc), galactose, and asialofetuin. The adherence of amebae to fixed human colonic mucosa was also GalNAc inhibitable. Greater adherence was found with unfixed rat colonic mucosa (40.9%) and was not GalNAc inhibitable unless the tissue was first exposed to trypsin. However, GalNAc did inhibit the adherence of amebae to unfixed rat submucosa. Glutaraldehyde fixation of amebae inactivates known amebic adhesion proteins; there was a markedly decreased adherence of fixed amebae to trypsin-exposed mucosa or fixed rat colonic mucosa. However, fixed or viable amebae had equal levels of adherence to unfixed rat colonic mucosa, suggesting the presence of a host adhesion protein that binds to receptors on amebae. Human (10%) and rabbit (5%) immune sera reduced the adherence of viable amebae to fixed rat colonic mucosa. We concluded that the GalNAc-inhibitable adhesion protein on the surface of E. histolytica trophozoites mediated adherence to fixed rat mucosa, fixed human colonic mucosa, trypsin-exposed unfixed rat mucosa, and unfixed rat submucosa. The surface of unfixed rat colonic mucosa contained a glutaraldehyde- and trypsin-sensitive host adhesion protein, perhaps in the overlying mucus blanket, which bound viable or fixed E. histolytica trophozoites. Images PMID:2580787

  19. Myofibroblasts and colonic anastomosis healing in Wistar rats

    PubMed Central

    2011-01-01

    Background The myofibroblasts play a central role in wound healing throughout the body. The process of wound healing in the colon was evaluated with emphasis on the role of myofibroblasts. Methods One hundred male Wistar rats weighing 274 ± 9.1 g (mean age: 3.5 months) were used. A left colonic segment was transected and the colon was re-anastomosed. Animals were randomly divided into two groups. The first group experimental animals (n = 50) were sacrificed on postoperative day 3, while the second group rats (n = 50) were sacrificed on postoperative day 7. Healing of colonic anastomosis was studied in terms of anastomotic bursting pressure, as well as myofibroblastic reaction and expression of α-smooth muscle actin (α-SMA), adhesion formation, inflammatory reaction and neovascularization. Results The mean anastomotic bursting pressure increased from 20.6 ± 3.5 mmHg on the 3rd postoperative day to 148.8 ± 9.6 Hg on the 7th postoperative day. Adhesion formation was increased on the 7th day, as compared to the 3rd day. In addition, the myofibroblastic reaction was more profound on the 7th postoperative day in comparison with the 3rd postoperative day. The staining intensity for α-SMA was progressive from the 3rd to the 7th postoperative day. On the 7th day the α-SMA staining in the myofibroblats reached the level of muscular layer cells. Conclusions Our study emphasizes the pivotal role of myofibroblasts in the process of colonic anastomosis healing. The findings provide an explanation for the reduction in the incidence of wound dehiscence after the 7th postoperative day. PMID:21366898

  20. Intestinal Inflammation in Rats Induces Metallothionein in Colonic Submucosa

    PubMed Central

    Al-Gindan, Yasmin; Shawarby, Mohammed; Noto, Amy; Taylor, Carla G.

    2009-01-01

    The aim of the current study was to determine if induction of metallothionein (MT) via acute or chronic dietary zinc supplementation attenuates intestinal inflammation, and to investigate the relationship with site-specific intestinal MT determined by immunolocalization. Growing rats were assigned to zinc-deficient (ZD), acute zinc-treated (ZT), pair-fed, control or chronic Zn-supplemented (ZS) groups. Half the rats in each dietary group received 5% dextran sulphate sodium (DSS) in their drinking water for 4 days. DSS treatment produced acute intestinal inflammation in the colon only, however, dietary zinc deficiency, acute zinc treatment or chronic zinc supplementation did not alter the severity of ulceration. Serum zinc concentrations were attenuated in the DSS-challenged ZT and ZS groups suggesting that zinc was being utilized in some capacity in response to inflammation. DSS-challenge induced MT immunostaining in the colonic submucosa, however, MT was not associated with histological improvements in the present study. The site-specific MT induction in colonic submucosa during intestinal inflammation requires further clarification as a component of the host defense. PMID:19308267

  1. Inhibitory effect of succinic acid on epithelial cell proliferation of colonic mucosa in rats.

    PubMed

    Inagaki, Akiko; Ichikawa, Hirofumi; Sakata, Takashi

    2007-08-01

    Microbial breakdown of carbohydrates in the large intestine mainly produces short-chain fatty acids (SCFA). SCFA stimulate epithelial cell proliferation of the digestive tract in vivo. Succinic acid sometimes accumulates in the colonic lumen. However, the effect of succinic acid on colonic epithelial cell proliferation is unknown. Thus, we planned to clarify the influence of succinic acid on colonic epithelial cell proliferation in vivo. We continuously administered infusate with or without succinic acid (100 mM) into the distal colon of rats for 6 d and measured accumulated mitosis per crypt of distal colon of these rats. Succinic acid infused into rat colons significantly inhibited colonic cell proliferation and reduced crypt size. These results clearly indicated the inhibitory effects of succinic acid on colonic epithelial cell proliferation in vivo. PMID:17934246

  2. Red meat and colon cancer: dietary haem, but not fat, has cytotoxic and hyperproliferative effects on rat colonic epithelium.

    PubMed

    Sesink, A L; Termont, D S; Kleibeuker, J H; Van Der Meer, R

    2000-10-01

    High intake of red meat is associated with an increased risk of colon cancer. It has been suggested that fat from red meat is responsible, because high fat intake increases the concentration of cytotoxic lipids in the colon. Experimental studies have not unequivocally supported such a role for fat, however. Recently, we showed that dietary haem, which is abundant in red meat, increased colonic cytotoxicity and epithelial proliferation. In this study, we wanted to clarify whether dietary fat affects colon cancer risk by itself or by modulating the detrimental effects of haem on the colonic epithelium. Rats were fed control or haem-supplemented diets with 10%, 25% or 40% of the energy derived from fat for 14 days. Faeces were collected for biochemical analyses. Colonic cytotoxicity was determined from the degree of lysis of erythrocytes by faecal water. Colonic epithelial proliferation was measured in vivo using [(3)H]thymidine incorporation. Increasing the fat content of the control diets stimulated faecal disposal of both fatty acids and bile acids. It also increased the concentration of fatty acids, but not that of bile acids, in faecal water in control rats. The cytolytic activity of faecal water and colonic epithelial proliferation were unaffected. Dietary haem increased faecal cation content and cytolytic activity of faecal water at all fat levels, suggesting that the colonic mucosa was exposed to high amounts of luminal irritants. This effect was smaller in rats on the low-fat diet. Dietary haem also increased colonic epithelial proliferation at all fat levels. The haem-induced effects were independent of fatty acids or bile acids in the faecal water. In western societies, 30-40% of ingested energy is supplied by dietary fat, so our results suggest that the association between consumption of red meat and risk of colon cancer is mainly due to its haem content, and is largely independent of dietary fat content. PMID:11023550

  3. Boron absorption imaging in rat lung colon adenocarcinoma metastases

    NASA Astrophysics Data System (ADS)

    Altieri, S.; Bortolussi, S.; Bruschi, P.; Fossati, F.; Vittor, K.; Nano, R.; Facoetti, A.; Chiari, P.; Bakeine, J.; Clerici, A.; Ferrari, C.; Salvucci, O.

    2006-05-01

    Given the encouraging results from our previous work on the clinical application of BNCT on non-resectable, chemotherapy resistant liver metastases, we explore the possibility to extend our technique to lung metastases. A fundamental requirement for BNCT is achieving higher 10B concentrations in the metastases compared to those in healthy tissue. For this reason we developed a rat model with lung metastases in order to study the temporal distribution of 10B concentration in tissues and tumoral cells. Rats with induced lung metastases from colon adenocarcinoma were sacrificed two hours after intraperitoneal Boronphenylalanine infusion. The lungs were harvested, frozen in liquid nitrogen and subsequently histological sections underwent neutron autoradiography in the nuclear reactor Triga Mark II, University of Pavia. Our findings demonstrate higher Boron uptake in tumoral nodules compared to healthy lung parenchyma 2 hours after Boronphenylalanine infusion.

  4. Proliferative and morphologic changes in rat colon following bypass surgery.

    PubMed Central

    Barkla, D. H.; Tutton, P. J.

    1985-01-01

    In this study the proliferative and morphologic changes that occur in the colon of normal and dimethylhydrazine-treated rats following surgical bypass of the middle third of the colon are reported. Proliferative changes were measured by estimating accumulated mitotic indexes following vinblastine treatment and morphologic changes were observed with the use of light microscopy and scanning electron microscopy. Data were collected on Days 0, 7, 14, 30, and 72 after surgery. The results show that surgical bypass produces contrasting effects in the segments proximal to and distal to the suture line. In the proximal segment there was morphologic evidence of hyperplasia, although proliferative activity was unchanged except for an increase at 7 days in normal rats. In the distal segment there was a long-lived increase in the mitotic index, although morphologic changes were not seen. The results for DMH-treated rats were similar to those in normal rats. Groups of isolated dysplastic epithelial cells were often seen in the submucosa adjacent to sutures up to 72 days after surgery. Increased lymphoid infiltration was seen in segments proximal to but not distal to the suture line. It is hypothesized that the different responses of the proximal and distal segments may be related to the different embryologic origins of those segments. It is also hypothesized that the seeding of the submucosa with epithelial cells during suturing may be a factor in tumor recurrence. Images Figure 19 Figure 20 Figure 21 Figure 22 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 PMID:4014432

  5. Disodium Cromoglycate Reverses Colonic Visceral Hypersensitivity and Influences Colonic Ion Transport in a Stress-Sensitive Rat Strain

    PubMed Central

    Carroll, Siobhan Yvonne; O’Mahony, Siobhain Mary; Grenham, Susan; Cryan, John Francis; Hyland, Niall Patrick

    2013-01-01

    The interface between psychiatry and stress-related gastrointestinal disorders (GI), such as irritable bowel syndrome (IBS), is well established, with anxiety and depression the most frequently occurring comorbid conditions. Moreover, stress-sensitive Wistar Kyoto (WKY) rats, which display anxiety- and depressive-like behaviors, exhibit GI disturbances akin to those observed in stress-related GI disorders. Additionally, there is mounting preclinical and clinical evidence implicating mast cells as significant contributors to the development of abdominal visceral pain in IBS. In this study we examined the effects of the rat connective tissue mast cell (CTMC) stabiliser, disodium cromoglycate (DSCG) on visceral hypersensitivity and colonic ion transport, and examined both colonic and peritoneal mast cells from stress-sensitive WKY rats. DSCG significantly decreased abdominal pain behaviors induced by colorectal distension in WKY animals independent of a reduction in colonic rat mast cell mediator release. We further demonstrated that mast cell-stimulated colonic ion transport was sensitive to inhibition by the mast cell stabiliser DSCG, an effect only observed in stress-sensitive rats. Moreover, CTMC-like mast cells were significantly increased in the colonic submucosa of WKY animals, and we observed a significant increase in the proportion of intermediate, or immature, peritoneal mast cells relative to control animals. Collectively our data further support a role for mast cells in the pathogenesis of stress-related GI disorders. PMID:24367692

  6. Disodium cromoglycate reverses colonic visceral hypersensitivity and influences colonic ion transport in a stress-sensitive rat strain.

    PubMed

    Carroll, Siobhan Yvonne; O'Mahony, Siobhain Mary; Grenham, Susan; Cryan, John Francis; Hyland, Niall Patrick

    2013-01-01

    The interface between psychiatry and stress-related gastrointestinal disorders (GI), such as irritable bowel syndrome (IBS), is well established, with anxiety and depression the most frequently occurring comorbid conditions. Moreover, stress-sensitive Wistar Kyoto (WKY) rats, which display anxiety- and depressive-like behaviors, exhibit GI disturbances akin to those observed in stress-related GI disorders. Additionally, there is mounting preclinical and clinical evidence implicating mast cells as significant contributors to the development of abdominal visceral pain in IBS. In this study we examined the effects of the rat connective tissue mast cell (CTMC) stabiliser, disodium cromoglycate (DSCG) on visceral hypersensitivity and colonic ion transport, and examined both colonic and peritoneal mast cells from stress-sensitive WKY rats. DSCG significantly decreased abdominal pain behaviors induced by colorectal distension in WKY animals independent of a reduction in colonic rat mast cell mediator release. We further demonstrated that mast cell-stimulated colonic ion transport was sensitive to inhibition by the mast cell stabiliser DSCG, an effect only observed in stress-sensitive rats. Moreover, CTMC-like mast cells were significantly increased in the colonic submucosa of WKY animals, and we observed a significant increase in the proportion of intermediate, or immature, peritoneal mast cells relative to control animals. Collectively our data further support a role for mast cells in the pathogenesis of stress-related GI disorders. PMID:24367692

  7. The utility of Apc-mutant rats in modeling human colon cancer

    PubMed Central

    Irving, Amy A.; Yoshimi, Kazuto; Hart, Marcia L.; Parker, Taybor; Clipson, Linda; Ford, Madeline R.; Kuramoto, Takashi; Dove, William F.; Amos-Landgraf, James M.

    2014-01-01

    Prior to the advent of genetic engineering in the mouse, the rat was the model of choice for investigating the etiology of cancer. Now, recent advances in the manipulation of the rat genome, combined with a growing recognition of the physiological differences between mice and rats, have reignited interest in the rat as a model of human cancer. Two recently developed rat models, the polyposis in the rat colon (Pirc) and Kyoto Apc Delta (KAD) strains, each carry mutations in the intestinal-cancer-associated adenomatous polyposis coli (Apc) gene. In contrast to mouse models carrying Apc mutations, in which cancers develop mainly in the small intestine rather than in the colon and there is no gender bias, these rat models exhibit colonic predisposition and gender-specific susceptibility, as seen in human colon cancer. The rat also provides other experimental resources as a model organism that are not provided by the mouse: the structure of its chromosomes facilitates the analysis of genomic events, the size of its colon permits longitudinal analysis of tumor growth, and the size of biological samples from the animal facilitates multiplexed molecular analyses of the tumor and its host. Thus, the underlying biology and experimental resources of these rat models provide important avenues for investigation. We anticipate that advances in disease modeling in the rat will synergize with resources that are being developed in the mouse to provide a deeper understanding of human colon cancer. PMID:25288683

  8. Dietary exposure to soy or whey proteins alters colonic global gene expression profiles during rat colon tumorigenesis

    PubMed Central

    Xiao, Rijin; Badger, Thomas M; Simmen, Frank A

    2005-01-01

    Background We previously reported that lifetime consumption of soy proteins or whey proteins reduced the incidence of azoxymethane (AOM)-induced colon tumors in rats. To obtain insights into these effects, global gene expression profiles of colons from rats with lifetime ingestion of casein (CAS, control diet), soy protein isolate (SPI), and whey protein hydrolysate (WPH) diets were determined. Results Male Sprague Dawley rats, fed one of the three purified diets, were studied at 40 weeks after AOM injection and when tumors had developed in some animals of each group. Total RNA, purified from non-tumor tissue within the proximal half of each colon, was used to prepare biotinylated probes, which were hybridized to Affymetrix RG_U34A rat microarrays containing probes sets for 8799 rat genes. Microarray data were analyzed using DMT (Affymetrix), SAM (Stanford) and pair-wise comparisons. Differentially expressed genes (SPI and/or WPH vs. CAS) were found. We identified 31 induced and 49 repressed genes in the proximal colons of the SPI-fed group and 44 induced and 119 repressed genes in the proximal colons of the WPH-fed group, relative to CAS. Hierarchical clustering identified the co-induction or co-repression of multiple genes by SPI and WPH. The differential expression of I-FABP (2.92-, 3.97-fold down-regulated in SPI and WPH fed rats; P = 0.023, P = 0.01, respectively), cyclin D1 (1.61-, 2.42-fold down-regulated in SPI and WPH fed rats; P = 0.033, P = 0.001, respectively), and the c-neu proto-oncogene (2.46-, 4.10-fold down-regulated in SPI and WPH fed rats; P < 0.001, P < 0.001, respectively) mRNAs were confirmed by real-time quantitative RT-PCR. SPI and WPH affected colonic neuro-endocrine gene expression: peptide YY (PYY) and glucagon mRNAs were down-regulated in WPH fed rats, whereas somatostatin mRNA and corresponding circulating protein levels, were enhanced by SPI and WPH. Conclusions The identification of transcripts co- or differentially-regulated by SPI

  9. Cilengitide inhibits metastatic bone colonization in a nude rat model.

    PubMed

    Bretschi, Maren; Merz, Maximilian; Komljenovic, Dorde; Berger, Martin R; Semmler, Wolfhard; Bäuerle, Tobias

    2011-10-01

    Integrins αvβ3 and αvβ5 are considered to play an important role in the pathogenesis of breast cancer bone metastases. This study investigates the effects of the αvβ3/αvβ5 integrin-specific inhibitor cilengitide during early metastatic bone colonization. The impact of cilengitide on the migration, invasion and proliferation of MDA-MB-231 human breast carcinoma cells as well as on bone resorption by osteoclasts was investigated in vitro. For in vivo experiments, nude rats were treated with cilengitide for 30 days starting one day after site-specific tumor cell inoculation in the hind leg, and the course of metastatic changes in bone was followed using flat-panel volumetric computed tomography (VCT) and magnetic resonance imaging (MRI). Vascular changes in bone metastases were investigated using dynamic contrast-enhanced (DCE-) MRI-derived parameters amplitude A and exchange rate coefficient kep. In vitro, cilengitide treatment resulted in a decrease in proliferation, migration and invasion of MDA-MB-231 cells, as well as of osteoclast activity. In vivo, the development of bone metastasis in the hind leg of rats was not prevented by adjuvant cilengitide treatment, but cilengitide reduced the volumes of osteolytic lesions and respective soft tissue tumors of developing bone metastases as assessed with VCT and MRI, respectively. DCE-MRI revealed significant changes in the A and kep parameters including decreased relative blood volume and increased vessel permeability after cilengitide treatment indicating vessel remodeling. In conclusion, during early pathogenic processes of bone colonization, cilengitide treatment exerted effects on tumor cells, osteoclasts and vasculature reducing the skeletal lesion size of experimental skeletal metastases. PMID:21725616

  10. Candida albicans Airway Colonization Facilitates Subsequent Acinetobacter baumannii Pneumonia in a Rat Model.

    PubMed

    Tan, Xiaojiang; Chen, Ruilan; Zhu, Song; Wang, Huijun; Yan, Dongxing; Zhang, Xiangdong; Farmakiotis, Dimitrios; Mylonakis, Eleftherios

    2016-06-01

    The objective of the study was to determine the effects of Candida albicans respiratory tract colonization on Acinetobacter baumannii pneumonia in a rat model. Rats were colonized with C. albicans by instillation of 3 × 10(6) CFU into their airways, while sterile saline was instilled in the control group. The colonized rats were further divided into two groups: treated with amphotericin B or not. The rats were subsequently infected with A. baumannii (10(8) CFU by tracheobronchial instillation). A. baumannii lung CFU counts, cytokine lung levels, and rates of A. baumannii pneumonia were compared between groups. In vitro expression of A. baumannii virulence genes was measured by reverse transcription (RT)-PCR after 24-hour incubation with C. albicans or with Mueller-Hinton (MH) broth alone. Rats with Candida colonization developed A. baumannii pneumonia more frequently and had higher A. baumannii CFU burdens and heavier lungs than controls. After A. baumannii infection, lung interleukin 17 (IL-17) concentrations were lower and gamma interferon (IFN-γ) concentrations were higher in Candida-colonized rats than in controls. Candida-colonized rats treated with amphotericin B had a decreased rate of A. baumannii pneumonia and lower IFN-γ levels but higher IL-17 levels than untreated rats. Expression of basC, barB, bauA, ptk, plc2, and pld2 was induced while expression of ompA and abaI was suppressed in A. baumannii cultured in the presence of C. albicans C. albicans colonization facilitated the development of A. baumannii pneumonia in a rat model. Among Candida-colonized rats, antifungal treatment lowered the incidence of A. baumannii pneumonia. These findings could be due to modification of the host immune response and/or expression of A. baumannii virulence genes by Candida spp. PMID:27001817

  11. Hydroxy-α sanshool induces colonic motor activity in rat proximal colon: a possible involvement of KCNK9.

    PubMed

    Kubota, Kunitsugu; Ohtake, Nobuhiro; Ohbuchi, Katsuya; Mase, Akihito; Imamura, Sachiko; Sudo, Yuka; Miyano, Kanako; Yamamoto, Masahiro; Kono, Toru; Uezono, Yasuhito

    2015-04-01

    Various colonic motor activities are thought to mediate propulsion and mixing/absorption of colonic content. The Japanese traditional medicine daikenchuto (TU-100), which is widely used for postoperative ileus in Japan, accelerates colonic emptying in healthy humans. Hydroxy-α sanshool (HAS), a readily absorbable active ingredient of TU-100 and a KCNK3/KCNK9/KCNK18 blocker as well as TRPV1/TRPA1 agonist, has been investigated for its effects on colonic motility. Motility was evaluated by intraluminal pressure and video imaging of rat proximal colons in an organ bath. Distribution of KCNKs was investigated by RT-PCR, in situ hybridization, and immunohistochemistry. Current and membrane potential were evaluated with use of recombinant KCNK3- or KCNK9-expressing Xenopus oocytes and Chinese hamster ovary cells. Defecation frequency in rats was measured. HAS dose dependently induced strong propulsive "squeezing" motility, presumably as long-distance contraction (LDC). TRPV1/TRPA1 agonists induced different motility patterns. The effect of HAS was unaltered by TRPV1/TRPA1 antagonists and desensitization. Lidocaine (a nonselective KCNK blocker) and hydroxy-β sanshool (a geometrical isomer of HAS and KCNK3 blocker) also induced colonic motility as a rhythmic propagating ripple (RPR) and a LDC-like motion, respectively. HAS-induced "LDC," but not lidocaine-induced "RPR," was abrogated by a neuroleptic agent tetrodotoxin. KCNK3 and KCNK9 were located mainly in longitudinal smooth muscle cells and in neural cells in the myenteric plexus, respectively. Administration of HAS or TU-100 increased defecation frequency in normal and laparotomy rats. HAS may evoke strong LDC possibly via blockage of the neural KCNK9 channel in the colonic myenteric plexus. PMID:25634809

  12. Nexrutine inhibits azoxymethane-induced colonic aberrant crypt formation in rat colon and induced apoptotic cell death in colon adenocarcinoma cells.

    PubMed

    Alam, Shamshad; Pal, Anu; Kumar, Rahul; Mir, Snober S; Ansari, Kausar M

    2016-08-01

    Colon cancer is the third most common cause of death in the United States. Therefore, new preventive strategies are warranted for preventing colon cancer. Nexrutine (NX), an herbal extract from Phellodendron amurense, has been shown to have anti-inflammatory, anti-microbial and anti-cancer activity for various tissue specific cancers, but its chemopreventive efficacy has not been evaluated against colon cancer. Here, we explored the mechanism of chemopreventive/chemotherapeutic efficacy of NX against colon cancer. We found that dietary exposure of NX significantly reduced the number of azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rats. In addition, significant inhibition in AOM-induced cell proliferation and reduced expression of the inflammatory markers COX-2, iNOS as well as the proliferative markers PCNA and cyclin D1 were also seen. Moreover, NX exposure significantly enhanced apoptosis in the colon of AOM treated rats. Furthermore, in in vitro studies, NX (2.5, 5, 10 μg/ml, 48 h) decreased cell survival and colony formation while inducing G0/G1 cell cycle arrest and apoptosis in colon adenocarcinoma cells COLO205 and HCT-15. However, NX had minimal cytotoxic effect on IEC-6 normal rat intestinal cells, suggesting its high therapeutic index. NX treatment also modulates the level of Bax and Bcl-2 proteins along with cytochrome c release, cleavage and enhanced expression of poly (adenosine diphosphate-ribose) polymerase as well as the catalytic activity of caspase 3 and caspase 9 in both COLO205 and HCT-15 cells. Based on these in vivo and in vitro findings, we suggest that NX could be useful candidate agent for colon cancer chemoprevention and treatment. © 2015 Wiley Periodicals, Inc. PMID:26259065

  13. Sutureless colon anastomosis with fibrin glue in the rat.

    PubMed

    Haukipuro, K A; Hulkko, O A; Alavaikko, M J; Laitinen, S T

    1988-08-01

    The only technique available for creating an intestinal anastomosis without tissue strangulation is gluing. Theoretically, this could lead to a higher hydroxyproline content and greater mechanical strength than in a sutured anastomosis. To test the hypothesis, 83 rats underwent left colon resection and inverted primary anastomosis with either one layer of sutures (NG group) or fibrin glue (FG group). Seven-day FG anastomoses showed less adhesions (P = .02) but one subclinical leakage and a further radiologic one, compared with a greater amount of adhesions but no leakages in the NG group. The mean bursting pressures (mmHg) in the FG and NG groups, respectively, were 25 +/- 20 (SD) and 63 +/- 23 (N.S.) 30 minutes after surgery, 107 +/- 33 and 115 +/- 30 after one day, 81 +/- 31 and 133 +/- 26 (P less than .001) after four days, and 161 +/- 36 and 175 +/- 24 after seven days. The somewhat earlier rise in hydroxyproline content in the glued anastomoses did not lead to significant intergroup differences. The glued anastomoses were thus weak during the critical lag period of healing. Also, by preventing adhesion formation, the glue may reduce the extra blood supply from perianastomotic vessels. The outcomes might have differed more under demanding experimental or clinical situations. PMID:2456902

  14. Oxytocin decreases colonic motility of cold water stressed rats via oxytocin receptors

    PubMed Central

    Yang, Xiao; Xi, Tao-Fang; Li, Yu-Xian; Wang, Hai-Hong; Qin, Ying; Zhang, Jie-Ping; Cai, Wen-Ting; Huang, Meng-Ting; Shen, Ji-Qiao; Fan, Xi-Min; Shi, Xuan-Zheng; Xie, Dong-Ping

    2014-01-01

    AIM: To investigate whether cold water intake into the stomach affects colonic motility and the involvement of the oxytocin-oxytocin receptor pathway in rats. METHODS: Female Sprague Dawley rats were used and some of them were ovariectomized. The rats were subjected to gastric instillation with cold (0-4 °C, cold group) or room temperature (20-25 °C, control group) saline for 14 consecutive days. Colon transit was determined with a bead inserted into the colon. Colonic longitudinal muscle strips were prepared to investigate the response to oxytocin in vitro. Plasma concentration of oxytocin was detected by ELISA. Oxytocin receptor expression was investigated by Western blot analysis. Immunohistochemistry was used to locate oxytocin receptors. RESULTS: Colon transit was slower in the cold group than in the control group (P < 0.05). Colonic smooth muscle contractile response to oxytocin decreased, and the inhibitory effect of oxytocin on muscle contractility was enhanced by cold water intake (0.69 ± 0.08 vs 0.88 ± 0.16, P < 0.05). Atosiban and tetrodotoxin inhibited the effect of oxytocin on colonic motility. Oxytocin receptors were located in the myenteric plexus, and their expression was up-regulated in the cold group (P < 0.05). Cold water intake increased blood concentration of oxytocin, but this effect was attenuated in ovariectomized rats (286.99 ± 83.72 pg/mL vs 100.56 ± 92.71 pg/mL, P < 0.05). However, in ovariectomized rats, estradiol treatment increased blood oxytocin, and the response of colonic muscle strips to oxytocin was attenuated. CONCLUSION: Cold water intake inhibits colonic motility partially through oxytocin-oxytocin receptor signaling in the myenteric nervous system pathway, which is estrogen dependent. PMID:25152590

  15. Modifying effects of Terminalia catappa on azoxymethane-induced colon carcinogenesis in male F344 rats.

    PubMed

    Morioka, T; Suzui, M; Nabandith, V; Inamine, M; Aniya, Y; Nakayama, T; Ichiba, T; Yoshimi, N

    2005-04-01

    The modifying effects of dietary administration of an herb, Terminalia catappa (TC), were investigated on rat colon carcinogenesis induced by a carcinogen azoxymethane (AOM). The number of aberrant crypt foci (ACF) and beta-catenin accumulated crypts (BCACs) in the colon, and proliferating cell nuclear antigen (PCNA) labelling index in the colonic epithelium were examined in a total of 36 male F344 rats. All animals were randomly divided into five experimental groups (4-10 rats in each group). At 6 weeks of age, rats in groups 1, 2 and 3 were given s.c. injections of AOM once a week for 2 weeks at a concentration of 20 mg/kg body weight. One week before the first injection of AOM, rats in groups 2 and 3 were fed a diet containing 0.02 and 0.1% TC, respectively, throughout the experiment. Rats in group 4 were fed a diet containing 0.1% TC. Rats in group 5 were served as untreated controls. All animals were sacrificed at the experimental week 5 after the start of the experiment. Oral administration of TC at both doses significantly decreased the numbers of both ACF/colon/rat (P<0.05 for 0.02% TC, P<0.005 for 0.1% TC) and BCAC/cm/rat (P<0.05 for both 0.02 and 0.1% TC), when compared with the control group (group 1). Colonic PCNA labelling index in groups 2 and 3 was also significantly lower than that in group 1 (P<0.001 for 0.02% TC, P<0.005 for 0.1% TC). These results suggest that TC has a potent short-term chemopreventive effect on biomarkers of colon carcinogenesis and this effect may be associated with the inhibition of the development of ACF and BCACs. PMID:15785313

  16. Apc-driven colon carcinogenesis in Pirc rat is strongly reduced by polyethylene glycol.

    PubMed

    Femia, Angelo Pietro; Becherucci, Caterina; Crucitta, Stefania; Caderni, Giovanna

    2015-11-01

    Polyethylene glycol (PEG) is one of the most powerful agents in reducing chemically induced carcinogenesis in rat colon. However, contrasting results in Min mice dampened the enthusiasm on this potentially strong and virtually safe, cancer chemopreventing agent. Pirc (F344/NTac-Apc (am1137) ) rats carrying a germline heterozygous mutation in the Apc gene, spontaneously develop multiple tumours in the colon thus modelling both familial adenomatous polyposis (FAP) and sporadic colorectal cancer (CRC). Given this similarity, we thought that these rats could be appropriate to test the efficacy of PEG 8000 in reducing carcinogenesis. Pirc male rats aged one month were treated with 5% PEG in drinking water for 2 or 6 months. Precancerous lesions were dramatically reduced after 2 months of PEG treatment (Mucin depleted foci (MDF)/colon were 99 ± 17 and 12 ± 8 in Controls and PEG-treated rats, respectively; p < 0.001; mean ± SD). Similarly, colon tumors were significantly reduced after 6 months of treatment (tumors/rat were 8.1 ± 2.3 and 3.6 ± 2.2 in Controls and PEG-treated rats, respectively; p < 0.05; mean ± SD). Colon proliferation, a parameter correlated to cancer risk, was also significantly lower in PEG-treated rats than in Controls, while apoptosis was not significantly affected. In conclusion, PEG markedly reduces colon carcinogenesis in Pirc rats mutated in Apc; we thus suggest that PEG may be used as chemopreventive agent to reduce cancer risk in FAP and CRC patients. PMID:25912754

  17. Colon Necrosis Due to Sodium Polystyrene Sulfonate with and without Sorbitol: An Experimental Study in Rats

    PubMed Central

    Ayoub, Isabelle; Oh, Man S.; Gupta, Raavi; McFarlane, Michael; Babinska, Anna; Salifu, Moro O.

    2015-01-01

    Introduction Based on a single rat study by Lillemoe et al, the consensus has been formed to implicate sorbitol rather than sodium polystyrene sulfonate (SPS) as the culprit for colon necrosis in humans treated with SPS and sorbitol. We tested the hypothesis that colon necrosis by sorbitol in the experiment was due to the high osmolality and volume of sorbitol rather than its chemical nature. Methods 26 rats underwent 5/6 nephrectomy. They were divided into 6 groups and given enema solutions under anesthesia (normal saline, 33% sorbitol, 33% mannitol, SPS in 33% sorbitol, SPS in normal saline, and SPS in distilled water). They were sacrificed after 48 hours of enema administration or earlier if they were very sick. The gross appearance of the colon was visually inspected, and then sliced colon tissues were examined under light microscopy. Results 1 rat from the sorbitol and 1 from the mannitol group had foci of ischemic colonic changes. The rats receiving SPS enema, in sorbitol, normal saline, distilled water, had crystal deposition with colonic necrosis and mucosal erosion. All the rats not given SPS survived until sacrificed at 48 h whereas 11 of 13 rats that received SPS in sorbitol, normal saline or distilled water died or were clearly dying and sacrificed sooner. There was no difference between sorbitol and mannitol when given without SPS. Conclusions In a surgical uremic rat model, SPS enema given alone or with sorbitol or mannitol seemed to cause colon necrosis and high mortality rate, whereas 33% sorbitol without SPS did not. PMID:26413782

  18. Anthocyanin-rich extracts inhibit multiple biomarkers of colon cancer in rats.

    PubMed

    Lala, Geeta; Malik, Minnie; Zhao, Cuiwei; He, Jian; Kwon, Youngjoo; Giusti, M Monica; Magnuson, Bernadene A

    2006-01-01

    The aim of the present study was to investigate the chemoprotective activity of anthocyanin-rich extracts (AREs) from bilberry (Vaccinium myrtillus L.), chokeberry (Aronia meloncarpa E.), and grape (Vitis vinifera) by assessing multiple biomarkers of colon cancer in male rats treated with a colon carcinogen, azoxymethane. Fischer 344 male rats were fed the AIN-93 diet (control) or AIN-93 diet supplemented with AREs for 14 wk. Biomarkers that were evaluated included the number and multiplicity of colonic aberrant crypt foci (ACF), colonic cell proliferation, urinary levels of oxidative DNA damage, and expression of cyclooxygenase (COX) genes. To assess the bioavailability, levels of anthocyanins in serum, urine, and feces were evaluated. Total ACF were reduced (P<0.05) in bilberry, chokeberry, and grape diet groups compared with the control group. The number of large ACF was also reduced (P<0.05) in bilberry and chokeberry ARE-fed rats. Colonic cellular proliferation was decreased in rats fed bilberry ARE and chokeberry ARE diets. Rats fed bilberry and grape ARE diets had lower COX-2 mRNA expression of gene. High levels of fecal anthocyanins and increased fecal mass and fecal moisture occurred in ARE-fed rats. There was also a significant reduction (P<0.05) in fecal bile acids in ARE-fed rats. The levels of urinary 8-hydroxyguanosine were similar among rats fed different diets. These results support our previous in vitro studies suggesting a protective role of AREs in colon carcinogenesis and indicate multiple mechanisms of action. PMID:16800776

  19. Relationship between oxidative damage and colon carcinogenesis in irradiated rats: influence of dietary countermeasures

    NASA Astrophysics Data System (ADS)

    Turner, Nancy; Sanders, Lisa; Wu, Guoyao; Davidson, Laurie; Ford, John; Braby, Leslie; Carroll, Raymond; Chapkin, Robert; Lupton, Joanne

    Galactic cosmic radiation not only kills colon epithelial cells, it also generates a cellular environment that can lead to oxidative DNA damage. We previously demonstrated that a diet containing fish oil and pectin protects against initiation of colon cancer by enhancing apoptotic removal of cells with oxidative DNA adducts (8-OHdG), and that apoptosis was highly correlated with colon cancer suppression. We hypothesized this diet combination will mitigate the oxidative damage occurring from radiation and thus reduce colon cancer. The experiment tested the effect of radiation (± 1 Gy, 1 GeV/n Fe ions) on redox balance, apoptosis, and 8-OHdG levels at initiation and colon tumor incidence. Diets contained fish oil or corn oil, and cellulose or pectin (2x2 factorial design). Rats received the diets 3 wk before irradiation (half of the rats), followed by azoxymethane (AOM) injections 10 and 17 d later (all rats). Just prior to AOM injection, irradiated fish oil/pectin rats had a more reduced redox state in colonocytes (lower GSSG, P < 0.05; higher GSH/GSSG ratio), which was not observed in irradiated corn oil/cellulose rats. A shift to a more oxidative state (lower GSH and GSH/GSSG ratio, P < 0.05) occurred between 6 and 12 h after AOM in the fish oil/pectin irradiated rats. Changes in redox balance likely contributed to lower 8-OHdG levels in colonocytes from rats consuming the fish oil diets. Dietary pectin enhanced (P < 0.04) apoptosis induction 12 h after AOM injection in irradiated rats. Similar to the 8-OHdG results, colon tumor incidence was 42% higher (P < 0.05) in rats fed corn oil vs fish oil diets. In summary, fish oil/pectin diets created a more reduced colon environment in irradiated rats that was evident 10 d after irradiation. The ensuing oxidative shift in those rats after AOM injection may have enhanced apoptosis; effectively eliminating more DNA damaged cells. Thus, inclusion of fish oil and pectin in diets for long-duration space flights should help

  20. Rat and human colonic mucins bind to and inhibit adherence lectin of Entamoeba histolytica.

    PubMed Central

    Chadee, K; Petri, W A; Innes, D J; Ravdin, J I

    1987-01-01

    Establishment of adherence by Entamoeba histolytica is mediated by a 170-kD Gal/GalNAc inhibitable lectin and is required for cytolysis and phagocytosis of mammalian target cells. We studied the biochemical mechanisms of the in vitro interaction between rat and human colonic mucins and axenic E. histolytica trophozoites. Crude mucus prevented amebic adherence to Chinese hamster ovary (CHO) cells by up to 70%. Purification of the colonic mucins by Sepharose 4B chromatography, nuclease digestion, and cesium chloride gradient centrifugation resulted in a 1,000-fold enrichment of the inhibitory mucins. Purified rat mucin inhibited amebic adherence to and cytolysis of homologous rat colonic epithelial cells. Oxidation and enzymatic cleavage of rat mucin Gal and GalNAc residues completely abrogated mucin inhibition of amebic adherence. The binding of rat 125I-mucin to amebae was galactose specific, saturable, reversible, and pH dependent. A monoclonal antibody specific for the 170-kD amebic Gal/GalNAc lectin completely inhibited the binding of rat 125I-mucin. Rat mucin bound to Affigel affinity purified the amebic lectin from conditioned medium. Colonic mucin glycoproteins act as an important host defense by binding to the parasite's adherence lectin, thus preventing amebic attachment to and cytolysis of host epithelial cells. Images PMID:2890655

  1. Colon cancer chemopreventive efficacy of silibinin through perturbation of xenobiotic metabolizing enzymes in experimental rats.

    PubMed

    Sangeetha, Nagarajan; Viswanathan, Periyaswamy; Balasubramanian, Thangavel; Nalini, Namasivayam

    2012-01-15

    Our findings reported so far demonstrate that silibinin modulates gut microbial enzymes, colonic oxidative stress and Wnt/β-catenin signaling, to exert its antiproliferative effect against 1,2 di-methylhydrazine (DMH) induced colon carcinogenesis. Since xenobiotic metabolizing enzymes play a crucial role in carcinogen activation and metabolism, we aimed to explore the effect of silibinin on xenobiotic metabolizing enzymes during DMH induced colon carcinogenesis. Male albino rats were randomly divided into six groups. Group 1 served as control and group 2 rats received 50mg/kg body weight of silibinin p.o. every day. Groups 3-6 rats were given DMH at a dose of (20mg/kg body weight subcutaneously) once a week for 15 weeks to induce colonic tumors. In addition to DMH, group 4 (initiation), group 5 (post-initiation) and group 6 (entire period) rats received silibinin (50mg/kg body weight, p.o., everyday) at different time points during the experimental period of 32 weeks. Rats exposed to DMH alone showed increased activities of phase I enzymes (cytochrome b5, cytochrome b5 reductase, cytochromeP450, cytochromeP450 reductase, cytochromP4502E1) and decreased activities of phase II enzymes (Uridine diphospho glucuronyl transferase, Glutathione-S-transferase and DT-Diaphorase) in the liver and colonic mucosa as compared to control rats. Silibinin supplementation modulates the xenobiotic metabolizing enzymes favoring carcinogen detoxification. Evaluation of lipid peroxidation and antioxidants status showed that silibinin supplementation counteracts DMH induced hepatic and circulatory oxidative stress. Tumor burden in experimental animals was assessed both macroscopically and microscopically in the colon tissues. Our findings emphasize the potential chemopreventive action of silibinin against DMH induced colon carcinogenesis. PMID:22115893

  2. Amelioration of azoxymethane induced-carcinogenesis by reducing oxidative stress in rat colon by natural extracts

    PubMed Central

    2014-01-01

    Background Azoxymethane (AOM) is a potent carcinogenic agent commonly used to induce colon cancer in rats; the cytotoxicity of AOM is considered to mediate oxidative stress. This study investigated the chemopreventive effect of three natural extracts [pomegranate peel extract (PomPE), papaya peel extract (PapPE) and seaweed extract (SE)] against AOM-induced oxidative stress and carcinogenesis in rat colon. Methods Eighty Sprague–Dawley rats (aged 4 weeks) were randomly divided into 8 groups (10 rats/group). Control group was fed a basal diet; AOM-treated group was fed a basal diet and received AOM intraperitonial injections for two weeks at a dose of 15 mg/kg bodyweight, whereas the other six groups were received oral supplementation of PomPE, PapPE or SE, in the presence or absence of AOM injection. All animals were continuously fed ad-libitum until aged 16 weeks, then all rats were sacrificed and the colon tissues were examined microscopically for pathological changes and aberrant crypt foci (ACF) development, genotoxicity (induced micronuclei (MN) cells enumeration), and glutathione and lipid peroxidation. Results Our results showed that AOM-induced ACF development and pathological changes in the colonic mucosal tissues, increased bone marrow MN cells and oxidative stress (glutathione depletion, lipid peroxidation) in rat colonic cells. The concomitant treatment of AOM with PomPE, PapPE or SE significantly ameliorated the cytotoxic effects of AOM. Conclusions The results of this study provide in-vivo evidence that PomPE, PapPE and SE reduced the AOM-induced colon cancer in rats, through their potent anti-oxidant activities. PMID:24533833

  3. Suppression of azoxymethane-induced colon cancer development in rats by dietary resistant starch.

    PubMed

    Le Leu, Richard K; Brown, Ian L; Hu, Ying; Esterman, Adrian; Young, Graeme P

    2007-10-01

    Resistant starch is a complex carbohydrate that reaches the colon where it can be fermented by the colonic microflora resulting in production of short chain fatty acids (SCFA), in particular butyrate. RS effects on colorectal tumourigenesis are contrasting and protection remains controversial. Butyrate has an important role as the preferred metabolic fuel and regulator of colonocyte proliferation, differentiation and apoptosis and may play a role in cancer prevention. Thus variation in butyrate production from different substrates might explain the variation in effect of RS. This study evaluated the hypothesis that feeding dietary resistant starch (as high amylose maize starch) would protect against azoxymethane (AOM)-colon carcinogenesis and favourably influence the colonic luminal environment. Male Sprague-Dawley rats (n = 90) were provided one of three diets: Control (without added dietary fibre or RS), 10% HAS (contained 100 g/kg raw high amylose maize starch) or 20% HAS (contained 200 g/kg high amylose maize starch). Rats were fed their experimental diets for four weeks after which they were injected with AOM (15 mg/kg) during the fifth and six week. Colons were resected (25 weeks post second injection) for evaluation of tumour formation, apoptosis, proliferating cell nuclear antigen (PCNA) labelling index and short chain fatty acid levels. Feeding resistant starch significantly reduced the incidence (p < 0.01) and multiplicity (p < 0.05) of adenocarcinomas in the colon compared to the Control diet. Both doses of HAS resulted in similar protection against colon tumourigenesis. Feeding RS significantly increased total SCFA concentrations, including butyrate in the distal colon. Apoptosis (p < 0.01) was also enhanced while PCNA labelling index was reduced (p < 0.01) in the distal colon with resistant starch feeding. The protective effect of consumption of RS as dietary high-amylose cornstarch against colon cancer development appears to be related to active

  4. Prevention of N-methylnitrosourea-induced colon tumorigenesis by ursodeoxycholic acid in F344 rats.

    PubMed

    Narisawa, T; Fukaura, Y; Terada, K; Sekiguchi, H

    1998-10-01

    Bile acids are known to promote colon carcinogenesis. However, there is one study showing that ursodeoxycholic acid (UDCA) supplemented in the diet at the concentration of 0.4% prevented azoxymethane-induced rat colon tumorigenesis. The aim of our study was to explore the inhibitory effect of a much smaller dose of UDCA on colon carcinogenesis in rats. One hundred 7-week-old F344 rats were given 2 mg of N-methylnitrosourea 3 times a week for 3 weeks by intrarectal instillation, and were fed a 0% (control), 0.4% or 0.08% UDCA-supplemented diet for the next 27 weeks. All the rats were killed and examined for tumor development at week 30. The tumor incidence and number were significantly lower and smaller, respectively, in the UDCA-fed rats than in the control rats: 40% and 36% vs. 68%; 0.5 +/- 0.1 (mean +/- SEM) and 0.4 +/- 0.1 vs. 1.0 +/- 0.2. All the tumors were located in the distal half of the colon and were plaque-shaped or polypoid, being well-differentiated adenocarcinomas restricted to the mucosa or submucosa. Bile acids in the feces and the blood obtained at weeks 20 and 30, respectively, were analyzed by HPLC. A significant increase of UDCA was confirmed in both the feces and the blood of the UDCA-fed rats compared with the control rats. The results suggest that the continuous feeding of a small dose of UDCA may prevent colon carcinogenesis. PMID:9849578

  5. Biomechanical and histomorphometric colon remodelling in STZ-induced diabetic rats.

    PubMed

    Zhao, Jingbo; Nakaguchi, Toshiya; Gregersen, Hans

    2009-08-01

    The histomorphologic and passive biomechanical properties were studied in the mid-colon of 16 non-diabetic and 20 streptozotocin (STZ)-induced diabetic rats (50 mg/kg STZ, ip). The diabetic rats were divided into groups living 4 and 8 weeks after the induction of diabetes (n = 10 for each group). The mechanical test was a ramp distension of fluid into the colon in vitro. The colon diameter and length were obtained from digitized images of the segments at pre-selected pressures and at the no-load and zero-stress states. Circumferential and longitudinal stresses and strains were computed from the length, diameter, and pressure data and from the zero-stress state geometry. The blood glucose level increased 3-4-fold in the diabetic rats compared with the controls (P < 0.001). Diabetes generated pronounced increases in the colon weight per length, wall thickness, and wall cross-sectional area (P < 0.001). Histologically, the thickness of all layers was increased during diabetes (P < 0.05), especially the mucosa layer. The opening angle, and absolute values of residual strain increased in the diabetic group (P < 0.05 and P < 0.01, respectively). Furthermore, diabetes increased the circumferential and longitudinal stiffness of the colon wall (P < 0.001). The observed changes in residual strain, opening angle, and stress-strain relation may be contributing factors to colonic dysfunction and abdominal pain in diabetic patients. PMID:18989775

  6. PCR Conditions for 16S Primers for Analysis of Microbes in the Colon of Rats

    PubMed Central

    Camacho, H.; Tuero, A. D.; Bacardí, D.; Palenzuela, D. O.; Aguilera, A.; Silva, J. A.; Estrada, R.; Gell, O.; Suárez, J.; Ancizar, J.; Brown, E.; Colarte, A. B.; Castro, J.; Novoa, L. I.

    2016-01-01

    The study of the composition of the intestinal flora is important to the health of the host, playing a key role in maintaining intestinal homeostasis and the evolution of the immune system. For these studies, various universal primers of the 16S rDNA gene are used in microbial taxonomy. Here, we report an evaluation of 5 universal primers to explore the presence of microbial DNA in colon biopsies preserved in RNAlater solution. The DNA extracted was used for the amplification of PCR products containing the variable (V) regions of the microbial 16S rDNA gene. The PCR products were studied by restriction fragment length polymorphism (RFLP) analysis and DNA sequence, whose percent of homology with microbial sequences reported in GenBank was verified using bioinformatics tools. The presence of microbes in the colon of rats was quantified by the quantitative PCR (qPCR) technique. We obtained microbial DNA from rat, useful for PCR analysis with the universal primers for the bacteria 16S rDNA. The sequences of PCR products obtained from a colon biopsy of the animal showed homology with the classes bacilli (Lactobacillus spp) and proteobacteria, normally represented in the colon of rats. The proposed methodology allowed the attainment of DNA of bacteria with the quality and integrity for use in qPCR, sequencing, and PCR-RFLP analysis. The selected universal primers provided knowledge of the abundance of microorganisms and the formation of a preliminary test of bacterial diversity in rat colon biopsies. PMID:27382362

  7. BPC-15 reduces trinitrobenzene sulfonic acid-induced colonic damage in rats.

    PubMed

    Veljaca, M; Lesch, C A; Pllana, R; Sanchez, B; Chan, K; Guglietta, A

    1995-01-01

    The effect of BPC-15 (Booly Protection Compound-15) was evaluated in a rat model of colonic injury. A single intracolonic administration of trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol induces severe colonic damage, which is characterized by areas of necrosis surrounded by areas of acute inflammation. The damage is associated with high myeloperoxidase (MPO) activity, mainly as a reflection of neutrophilic infiltration into the damaged tissue. In this study, 1 hr before a single intracolonic administration of 50 mg/kg of TNBS in 50% ethanol, the animals were treated with one of the following doses of BPC-15: 0.0001, 0.001, 0.01, 0.1, 1 or 10 nmol/kg administered i.p. or with a dose of 10 nmol/kg administered intracolonically. The animals were sacrificed 3 days later and the extent of colonic necrosis and hyperemia was measured with an image analyzer. The i.p. administration of BPC-15 significantly reduced the extent of TNBS-induced colonic damage in a dose-dependent manner. This was associated with a statistically significant and dose-dependent reduction in colonic tissue MPO activity. At the dose tested (10 nmol/kg), intracolonic administration of BPC-15 did not significantly reduce either the extent of the colonic damage or the increase in MPO activity induced by TNBS. In conclusion, this study showed that i.p. administration of BPC-15 reduced TNBS-induced colonic damage in rats. PMID:7815358

  8. Simple method for the preparation of single cell suspensions from normal and tumorous rat colonic mucosa.

    PubMed Central

    Perret, V; Lev, R; Pigman, W

    1977-01-01

    Viable single cell suspensions from rat colonic epithelium were obtained by using phosphate buffered saline containing 0-2 M mannitol. The method, which requires no prior enzyme treatment, provides undamaged cells in high yield within one hour. The procedure was also applied to neoplastic rat colonic tissue, which was induced by repeated intrarectal infusion of N-methyl-N-nitrosourea. Comparison between normal and neoplastic cells has shown that the latter have a higher nucleus: cytoplasm ratio and a higher metabolic activity. Images Figure PMID:873323

  9. Role of CRF receptor 1 in central CRF-induced stimulation of colonic propulsion in rats.

    PubMed

    Martínez, V; Taché, Y

    2001-03-01

    The CRF receptor subtype mediating the colonic and gastric motor responses to central CRF was investigated in conscious rats. CRF (0.6 microg/rat) injected intracerebroventicularly (i.c.v.) or 1 h water avoidance stress stimulated defecation (pellet/60 min: 4.1+/-1.0 and 8.7+/-0.7 respectively vs. 0.3+/-0.3 in i.c.v. vehicle/no stress). The CRF receptor 1 (CRF-R1) antagonist, NBI-27914 (50-100 microg/rat) injected i.c.v., abolished the colonic response to i.c.v. CRF and dose-dependently reduced that induced by water avoidance stress. NBI-27914 (100 microg/rat) injected peripherally did not influence the defecatory response to stress. The peptide CRF-R1/R2 antagonist, astressin (10 microg/rat, i.c.v.) inhibited the colonic motor response to i.c.v. CRF and stress similarly as NBI-27914 injected i.c.v. at 100 microg/rat. Intracisternal (i.c.) injection of astressin (10 microg/rat) also completely prevented CRF (0.6 g, i.c.)-induced delayed gastric emptying while i.c. NBI-27914 (50 or 100 microg) had no effect. These results indicate a differential role of central CRF receptor subtypes in the colonic stimulatory and gastric inhibitory motor responses to central CRF and that the CRF component of stress-related activation of colonic expulsion is primarily mediated by CRF-R1. PMID:11222989

  10. K+ transport by rat colon: adaptation to a low potassium diet

    SciTech Connect

    Tannen, R.L.; Marino, R.; Dawson, D.C.

    1986-03-01

    Recent studies with the isolated perfused rat kidney have demonstrated the existence of an intrinsic renal adaptation to conserve K+ in response to ingestion of a low K+ diet for 3 days. To determine whether the colon alters its K+ transport properties in a similar fashion, we measured transmural 86Rb fluxes across sheets of distal colonic epithelium under short-circuit conditions. Preliminary studies using a double-isotope technique demonstrated that 86Rb and 42K fluxes were similar; therefore 86Rb flux was considered equivalent to K+ flux. The distal half of the colon from each rat was divided into two segments, referred to as early and late distal colon. Experiments were carried out using rats fed a K+ -free, control (0.15 mmol/g), and high K+ (1.13 mmol/g) powdered diet of otherwise identical electrolyte content. Net K+ secretion (Jnet) by the early distal colon was reduced from 0.45 in the controls to -0.02 mueq X cm-2 X h-1 by a low K+ diet as a result of a decrease in serosal-to-mucosal flux (Jsm), with no change in mucosal-to-serosal flux (Jms). Conductance (GT) and short-circuit current (Isc) were unchanged. Jnet by the late distal colon averaged 0.17 in the controls and 0.01 mueq X cm-2 X h-1 with a low K+ diet, but this difference was not significant statistically. In comparison with the controls, a high K+ diet had no effect on Jnet by the early distal colon (0.48 mueq X cm-2 X h-1) but increased Jnet by the late distal colon substantially (0.77 mueq X cm-2 X h-1).

  11. Pineal gland function is required for colon antipreneoplastic effects of physical exercise in rats.

    PubMed

    Frajacomo, F T T; de Paula Garcia, W; Fernandes, C R; Garcia, S B; Kannen, V

    2015-10-01

    Light-at-night exposure enhances the risk of cancer. Colon cancer is among the most dangerous tumors affecting humankind. Physical exercise has shown positive effects against colon cancer. Here, we investigated whether pineal gland modulates antipreneoplastic effects of physical exercise in the colon. Surgical and non-surgical pineal impairments were performed to clarify the relationship between the pineal gland activity and manifestation of colonic preneoplastic lesions. Next, a progressive swimming training was applied in rats exposed or not to either non-surgical pineal impairment or carcinogen treatment for 10 weeks. Both surgical and non-surgical pineal impairments increased the development of colon preneoplasia. It was further found that impairing the pineal gland function, higher rates of DNA damage were induced in colonic epithelial and enteric glial cells. Physical exercise acted positively against preneoplasia, whereas impairing the pineal function with constant light exposure disrupts its positive effects on the development of preneoplastic lesions in the colon. This was yet related to increased DNA damage in glial cells and enteric neuronal activation aside from serum melatonin levels. Our findings suggest that protective effects of physical exercise against colon cancer are dependent on the pineal gland activity. PMID:25487536

  12. Spinal cord influences on the colonic myoelectrical activity of fed and fasted rats.

    PubMed Central

    Du, C; Ferré, J P; Ruckebusch, Y

    1987-01-01

    1. The myoelectrical activity of the large intestine of fed and fasted rats was recorded with chronically implanted nichrome wire electrodes after destruction of the spinal cord, after spinal cord transection, and after spinal anaesthesia. 2. After spinal cord ablation, the cyclical organization of the colonic electrical spiking activity, as well as the gastrocolic reflex and accompanying postprandial enhancement of the cyclical pattern of activity, persisted on the proximal and distal colon. On the transverse colon, however, the spiking activity was considerably increased. This latter effect obliterated the gastrocolic response due to feeding but not the subsequent postprandial enhancement of the cyclical pattern of activity. 3. After spinal cord transection, the level of spiking activity also increased on both the transverse and distal colon, but no major changes in cyclical activity or in postprandial responses were recorded. 4. Spinal anaesthesia produced by intrathecal lidocaine increased the motility of the transverse colon to a level which masked the gastrocolic reflex. 5. These results suggest a prevertebral ganglia and/or a local control mechanism for the cyclical organization of the spiking activity of the colon. The central control mechanisms involve mostly spinal inhibitory influences on the transverse colon and supraspinal inhibitory influences on the distal colon. PMID:3656127

  13. Impact of the Metabolic Activity of Streptococcus thermophilus on the Colon Epithelium of Gnotobiotic Rats*

    PubMed Central

    Rul, Françoise; Ben-Yahia, Leila; Chegdani, Fatima; Wrzosek, Laura; Thomas, Stéphane; Noordine, Marie-Louise; Gitton, Christophe; Cherbuy, Claire; Langella, Philippe; Thomas, Muriel

    2011-01-01

    The thermophilic lactic acid bacterium Streptococcus thermophilus is widely and traditionally used in the dairy industry. Despite the vast level of consumption of S. thermophilus through yogurt or probiotic functional food, very few data are available about its physiology in the gastrointestinal tract (GIT). The objective of the present work was to explore both the metabolic activity and host response of S. thermophilus in vivo. Our study profiles the protein expression of S. thermophilus after its adaptation to the GIT of gnotobiotic rats and describes the impact of S. thermophilus colonization on the colonic epithelium. S. thermophilus colonized progressively the GIT of germ-free rats to reach a stable population in 30 days (108 cfu/g of feces). This progressive colonization suggested that S. thermophilus undergoes an adaptation process within GIT. Indeed, we showed that the main response of S. thermophilus in the rat's GIT was the massive induction of the glycolysis pathway, leading to formation of lactate in the cecum. At the level of the colonic epithelium, the abundance of monocarboxylic acid transporter mRNAs (SLC16A1 and SLC5A8) and a protein involved in the cell cycle arrest (p27kip1) increased in the presence of S. thermophilus compared with germ-free rats. Based on different mono-associated rats harboring two different strains of S. thermophilus (LMD-9 or LMG18311) or weak lactate-producing commensal bacteria (Bacteroides thetaiotaomicron and Ruminococcus gnavus), we propose that lactate could be a signal produced by S. thermophilus and modulating the colon epithelium. PMID:21239485

  14. Proteomic Analysis of Urine Exosomes Reveals Renal Tubule Response to Leptospiral Colonization in Experimentally Infected Rats

    PubMed Central

    RamachandraRao, Satish P.; Matthias, Michael A.; Mondrogon, Chanthel-Kokoy; Aghania, Eamon; Park, Cathleen; Kong, Casey; Ishaya, Michelle; Madrigal, Assael; Horng, Jennifer; Khoshaba, Roni; Bounkhoun, Anousone; De Palma, Antonella; Agresta, Anna Maria; Awdishu, Linda; Naviaux, Robert K.; Vinetz, Joseph M.; Mauri, Pierluigi

    2015-01-01

    Background Infectious Leptospira colonize the kidneys of reservoir (e.g. rats) and accidental hosts such as humans. The renal response to persistent leptospiral colonization, as measured by urinary protein biosignatures, has not been systematically studied. Urinary exosomes--bioactive membrane-bound nanovesicles--contain cell-state specific cargo that additively reflect formation all along the nephron. We hypothesized that Leptospira-infection will alter the content of urine exosomes, and further, that these Leptospira-induced alterations will hold clues to unravel novel pathways related to bacterial-host interactions. Methodology/Principal findings Exosome protein content from 24 hour urine samples of Leptospira-infected rats was compared with that of uninfected rats using SDS-PAGE and liquid chromatography/tandem mass spectrometry (LC-MS/MS). Statistical models were used to identify significantly dysregulated proteins in Leptospira-infected and uninfected rat urine exosomes. In all, 842 proteins were identified by LC-MS/MS proteomics of total rat urine and 204 proteins associated specifically with exosomes. Multivariate analysis showed that 25 proteins significantly discriminated between uninfected control and infected rats. Alanyl (membrane) aminopeptidase, also known as CD13 topped this list with the highest score, a finding we validated by Western immunoblotting. Whole urine analysis showed Tamm-Horsfall protein level reduction in the infected rat urine. Total urine and exosome proteins were significantly different in male vs. female infected rats. Conclusions We identified exosome-associated renal tubule-specific responses to Leptospira infection in a rat chronic colonization model. Quantitative differences in infected male and female rat urine exosome proteins vs. uninfected controls suggest that urine exosome analysis identifies important differences in kidney function that may be of clinical and pathological significance. PMID:25793258

  15. The role of acetylcholine in the regulation of ion transport by rat colon mucosa

    PubMed Central

    Browning, J. G.; Hardcastle, Jacqueline; Hardcastle, P. T.; Sanford, P. A.

    1977-01-01

    1. Acetylcholine increases the potential difference across rat proximal colon both in vivo and in vitro. 2. There is a sigmoid relationship between the change in potential difference and the logarithm of the dose of acetylcholine. The dose—response curve is shifted to the left by neostigmine and to the right by atropine, suggesting that the action of acetylcholine is mediated by a muscarinic type of receptor. 3. The dose-response curve for acetylcholine in vivo is not altered by the ganglion-blocking agents hexamethonium and pentolinium, suggesting a direct effect of this transmitter on the colon. 4. Acetylcholine causes an increase in potential difference, a small decrease in resistance and hence a rise in the current generated by both normal and stripped everted sacs of rat colon. 5. In the absence of sodium, the calculated current change produced by acetylcholine is reduced, and the removal of chloride has a similar inhibitory effect. The absence of bicarbonate does not significantly affect the response. 6. Acetylcholine virtually abolished net sodium movement and induced net chloride secretion and these changes accounted for the increased short-circuit current. 7. Acetylcholine had no effect on oxygen consumption by rings of colon. 8. Tracts staining for acetylcholinesterase were observed running from the submucous plexus towards the mucosal epithelium. 9. This study shows that acetylcholine can influence ion movement by rat colonic mucosa and suggests that the autonomic nervous system might be involved in the regulation of transport mechanisms in this tissue. ImagesPlate 1 PMID:592212

  16. Effects of chronic dietary beer and ethanol consumption on experimental colonic carcinogenesis by azoxymethane in rats.

    PubMed

    Hamilton, S R; Hyland, J; McAvinchey, D; Chaudhry, Y; Hartka, L; Kim, H T; Cichon, P; Floyd, J; Turjman, N; Kessie, G

    1987-03-15

    Epidemiological studies have shown an association between consumption of alcoholic beverages, particularly beer, and carcinoma of the large bowel, especially the rectum. We studied the effects of chronic dietary beer and ethanol consumption on experimental colonic carcinogenesis, fecal bile acid and neutral sterol levels, fecal bacterial flora, and colonic epithelial DNA synthesis. Ten-week-old male Fischer 344 rats were pair fed throughout the study with Lieber-DeCarli-type liquid diets providing comparable total carbohydrates, proteins, fats, and calories. The diets provided 23 or 12% of calories as alcohol in beer (Hi-Beer and Lo-Beer groups), 18 or 9% of calories as reagent ethanol (Hi-EtOH and Lo-EtOH groups), or no alcohol (control group). After 3 weeks of dietary acclimatization, 10 weekly s.c. injections of the bowel carcinogen azoxymethane, 7 mg/kg, were given (weeks 1-10). At necropsy in week 26, the high alcohol groups (Hi-Beer and Hi-EtOH) showed a significantly reduced incidence of tumors in the right colon (42 and 46% versus 81% in control, P less than 0.01 and P = 0.02) but no effect on left colonic tumorigenesis. By contrast, the low alcohol groups (Lo-Beer and Lo-EtOH) showed a trend toward increased incidence and proportion of tumors in the left colon (incidence of 42 and 35% versus 15% in control, P = 0.06 for Lo-Beer; 28 and 30% of tumors in left colon versus 11%, P = 0.08 and P = 0.07) but no effect on right colonic tumorigenesis. Numbers of right colonic tumors were inversely correlated with alcohol consumption of all rats (r = -0.350, P less than 0.001), but left colonic tumors were not correlated. Fecal bile acid and neutral sterol levels, fecal bacterial counts, and colonic epithelial DNA synthesis did not correlate with the effects of alcohol consumption on colonic tumorigenesis. Our findings suggest that: modulation of experimental colonic tumorigenesis by chronic dietary beer and ethanol consumption was due to alcohol rather than other

  17. Diclofenac-β-cyclodextrin for colonic drug targeting: In vivo performance in rats.

    PubMed

    Vieira, Amélia C F; Serra, Arménio C; Veiga, Francisco J; Gonsalves, António M d'A Rocha; Basit, Abdul W; Murdan, Sudaxshina

    2016-03-16

    The aim of this in vivo study was to assess the ability of the prodrug conjugate diclofenac-β-cyclodextrin to release diclofenac in the colon following oral administration, using sulfapyridine (a metabolite of sulfasalazine) as a marker of colonic absorption. Two groups of rats were used; the test rats received a suspension containing the two prodrugs, diclofenac-β-cyclodextrin and sulfasalazine, while the control rats received a suspension containing the corresponding free drugs, sodium diclofenac and sulfapyridine. The rats were fasted overnight with free access to water before and throughout the first 12h of the study. Blood was collected from the tail vein at pre-determined time points and the plasma analyzed for the concentrations of diclofenac and sulfapyridine. Following the oral administration of the two prodrugs, a more extended absorption profile was observed and Cmax was achieved 10h post-dose, in contrast to rapid absorption of the free drugs (tmax of diclofenac being 1.3h, and that of sulfapyridine being 2.1h). In addition to a later tmax, conjugation of diclofenac to β-cyclodextrin also resulted in a reduced Cmax and a reduced AUC. The same tmax for diclofenac-β-cyclodextrin as for sulfasalazine confirms the colonic metabolism of diclofenac-β-cyclodextrin. This study shows the potential of this new cyclodextrin-based prodrug to target and release diclofenac specifically in the colon following oral administration. PMID:26784980

  18. Folate depletion impairs DNA excision repair in the colon of the rat

    PubMed Central

    Choi, S; Kim, Y; Weitzel, J; Mason, J

    1998-01-01

    Background/Aims—Diminished folate status appears to promote colonic carcinogenesis by, as of yet, undefined mechanisms. Impaired DNA repair plays a significant role in the evolution of many colon cancers. Since folate is essential for the de novo synthesis of nucleotides and since folate depletion has previously been associated with excessive DNA strand breaks, it was hypothesised that folate depletion may impair DNA repair. Studies were therefore performed to examine whether folate depletion affects the two major categories of DNA repair. 
Methods—Study 1: eight weanling male Sprague-Dawley rats were fed on diets containing either 0 or 8 mg folate/kg diet with 1% succinylsulphathiazole for four weeks. After viable colonocytes had been harvested, DNA excision repair was evaluated by a single cell gel electrophoresis assay. Study 2: eighteen animals were fed on similar diets for five weeks. Also in study 2, 18 additional rats were fed on the same defined diet without succinylsulphathiazole for 15 weeks. Weekly injections with the procarcinogen, 1,2-dimethylhydrazine (20 mg base/kg), were administered to the latter group of animals. Five microsatellite loci from different chromosomes were investigated for instability in hepatic and colonic DNA. 
Results—In study 1, a significantly retarded rate of DNA excision repair was observed in the folate deficient colonocytes compared with controls (p<0.05). In study 2, there was no evidence of instability at the five microsatellite loci associated with either short or long term folate depletion. 
Conclusions—Folate deficiency impairs DNA excision repair in rat colonic mucosa; a similar degree of deficiency, even when administered in conjunction with a colonic carcinogen, did not produce evidence of a widespread defect in mismatch repair. 

 Keywords: folate; colon cancer; DNA repair; single cell gel electrophoresis; microsatellite instability; rat PMID:9771411

  19. Fate of soluble carbohydrate in the colon of rats and man.

    PubMed

    Bond, J H; Levitt, M D

    1976-05-01

    The fate of glucose in the colon of rats and man was investigated by measuring breath 14CO2 and fecal 14C after direct instillation of 14C-labeled glucose, acetate, and lactate into the cecum. For the 6 h after administration of as much as 400 mg of [U-14C]-glucose to the rat and 12.5 g to man, 14CO2 excretion was as rapid after intracecal as after intragastric instillation. Less than 20% of 14C instilled into the cecum as glucose was recovered in feces and only about 15% of this fecal 14C was in a dialyzable form. The conversion of intracecally administered glucose to CO2 was dependent upon the presence of the colonic flora, as evidenced by the minimal excretion of 14CO2 after administration of [14C]glucose to germ-free rats. In contrast, acetate and lactate, fermentation products of glucose, were converted to CO2 as rapidly in germ-free rats as in their conventional counterparts. Measurement of O2 availability in the colonic lumen indicated that insufficient O2 was available for the aerobic metabolism of glucose by the colonic bacteria. These experiments suggest that the colon bacteria anaerobically metabolize most of the glucose to short-chain fatty acids, which are absorbed and oxidized by the host. Most of the remaining fecal glucose is converted to a larger molecular form that has limited osmotic activity. Thus, the colonic flora benefits the host by reducing the osmotic load of nonabsorbed carbohydrate and by making possible the salvage of a large percentage of the calories of carbohydrate, which is not absorbed in the small bowel. PMID:1262463

  20. Interleukin-6 Modulates Colonic Transepithelial Ion Transport in the Stress-Sensitive Wistar Kyoto Rat

    PubMed Central

    O’Malley, Dervla; Dinan, Timothy G.; Cryan, John F.

    2012-01-01

    Immunological challenge stimulates secretion of the pro-inflammatory cytokine interleukin (IL)-6, resulting in variety of biological responses. In the gastrointestinal tract, IL-6 modulates the excitability of submucosal neurons and stimulates secretion into the colonic lumen. When considered in the context of the functional bowel disorder, irritable bowel syndrome (IBS), where plasma levels of IL-6 are elevated, this may reflect an important molecular mechanism contributing to symptom flares, particularly in the diarrhea-predominant phenotype. In these studies, colonic ion transport, an indicator of absorption and secretion, was assessed in the stress-sensitive Wistar Kyoto (WKY) rat model of IBS. Mucosa-submucosal colonic preparations from WKY and control Sprague Dawley (SD) rats were mounted in Ussing chambers and the basal short circuit current (ISC) was electrophysiologically recorded and compared between the strains. Exposure to IL-6 (1 nM) stimulated a secretory current of greater amplitude in WKY as compared to SD samples. Furthermore, the observed IL-6-mediated potentiation of secretory currents evoked by veratridine and capsaicin in SD rats was blunted in WKY rats. Exposure to IL-6 also stimulated an increase in transepithelial resistance in both SD and WKY colonic tissue. These studies demonstrate that the neuroexcitatory effects of IL-6 on submucosal plexi have functional consequences with alterations in both colonic secretory activity and permeability. The IL-6-induced increase in colonic secretory activity appears to neurally mediated. Thus, local increases in IL-6 levels and subsequent activation of enteric neurons may underlie alterations in absorpto-secretory function in the WKY model of IBS. PMID:23162465

  1. Stimulation of epithelial cell proliferation of isolated distal colon of rats by continuous colonic infusion of ammonia or short-chain fatty acids is nonadditive.

    PubMed

    Ichikawa, H; Sakata, T

    1998-05-01

    Dietary fibers accelerate colonic epithelial cell proliferation at least in part by modulating bacterial metabolism in the large intestine. Ammonia and short-chain fatty acids (SCFA) are major metabolites of hindgut bacteria and are believed to affect epithelial cell kinetics of the colon. However, the effect of luminal ammonia itself and the possible interaction of ammonia with SCFA on colonic epithelial cell proliferation have not yet been studied. The colon of rats was surgically isolated and continuously administered infusates with saline, ammonia, SCFA or both into the isolated colon for 7 d in a two-way factorial design. On d 7, vincrystine sulfate was administered intravenously to cause metaphase arrest. The activity of epithelial cell proliferation in the distal colon was estimated by using a stathmokinetic method and by histologic examination. The crypt size was significantly larger in rats given infusates containing SCFA than in rats given infusates without SCFA. Infusion of ammonia or SCFA significantly stimulated colonic epithelial cell proliferation compared with the saline infusion. Infusion of both ammonia and SCFA resulted in accumulated mitoses per crypt that did not differ from the other three infusions although the value tended to be lower than when SCFA alone were infused. Thus, stimulation of epithelial cell proliferation by ammonia and SCFA is not additive, and the interaction between them should be considered when the effects of dietary fibers on gut epithelial proliferation are investigated. PMID:9566991

  2. Identification of bladder and colon afferents in the nodose ganglia of male rats.

    PubMed

    Herrity, April N; Rau, Kristofer K; Petruska, Jeffrey C; Stirling, David P; Hubscher, Charles H

    2014-11-01

    The sensory neurons innervating the urinary bladder and distal colon project to similar regions of the central nervous system and often are affected simultaneously by various diseases and disorders, including spinal cord injury. Anatomical and physiological commonalities between the two organs involve the participation of shared spinally derived pathways, allowing mechanisms of communication between the bladder and colon. Prior electrophysiological data from our laboratory suggest that the bladder also may receive sensory innervation from a nonspinal source through the vagus nerve, which innervates the distal colon as well. The present study therefore aimed to determine whether anatomical evidence exists for vagal innervation of the male rat urinary bladder and to assess whether those vagal afferents also innervate the colon. Additionally, the relative contribution to bladder and colon sensory innervation of spinal and vagal sources was determined. By using lipophilic tracers, neurons that innervated the bladder and colon in both the nodose ganglia (NG) and L6/S1 and L1/L2 dorsal root ganglia (DRG) were quantified. Some single vagal and spinal neurons provided dual innervation to both organs. The proportions of NG afferents labeled from the bladder did not differ from spinal afferents labeled from the bladder when considering the collective population of total neurons from either group. Our results demonstrate evidence for vagal innervation of the bladder and colon and suggest that dichotomizing vagal afferents may provide a neural mechanism for cross-talk between the organs. PMID:24845615

  3. Chemopreventive effect of sinapic acid on 1,2-dimethylhydrazine-induced experimental rat colon carcinogenesis.

    PubMed

    Balaji, C; Muthukumaran, J; Nalini, N

    2014-12-01

    Sinapic acid (SA) is a naturally occurring phenolic acid found in various herbal plants which is attributed with numerous pharmacological properties. This study was aimed to investigate the chemopreventive effect of SA on 1,2-dimethylhydrazine (DMH)-induced rat colon carcinogenesis. Rats were treated with DMH injections (20 mg kg(-1) bodyweight (b.w.) subcutaneously once a week for the first 4 consecutive weeks and SA (20, 40 and 80 mg kg(-1) b.w.) post orally for 16 weeks. At the end of the 16-week experimental period, all the rats were killed, and the tissues were evaluated biochemically. Our results reveal that DMH alone treatment decreased the levels/activities of lipid peroxidation by-products such as thiobarbituric acid reactive substances, conjugated dienes and antioxidants such as superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and reduced glutathione in the intestine and colonic tissues which were reversed on supplementation with SA. Moreover, the activities of drug-metabolizing enzymes of phase I (cytochrome P450 and P4502E1) were enhanced and those of phase II (glutathione-S-transferase, DT-diaphorase and uridine diphosphate glucuronosyl transferase) were diminished in the liver and colonic mucosa of DMH alone-treated rats and were reversed on supplementation with SA. All the above changes were supported by the histopathological observations of the rat liver and colon. These findings suggest that SA at the dose of 40 mg kg(-1) b.w. was the most effective dose against DMH-induced colon carcinogenesis, and thus, SA could be used as a potential chemopreventive agent. PMID:24532707

  4. Therapy effect of antiulcer agents on new chronic cysteamine colon lesion in rat.

    PubMed

    Sikiric, P; Seiwerth, S; Aralica, G; Perovic, D; Staresinic, M; Anic, T; Gjurasin, M; Prkacin, I; Separovic, J; Stancic-Rokotov, D; Lovric-Bencic, M; Mikus, D; Turkovic, B; Rotkvic, I; Mise, S; Rucman, R; Petek, M; Ziger, T; Sebecic, B; Ivasovic, Z; Jagic, V; Komericki, L; Balen, I; Boban-Blagaic, A; Sjekavica, I

    2001-01-01

    After demonstration that cysteamine induced duodenal lesions in gastrectomized rats, while a number of antiulcer drugs mitigated these lesions, it was shown that one single intrarectal (i.r.) cysteamine application produced severe colon lesions in acute studies in rats. Thus, the further focus was on the protracted effect of cysteamine challenge (400 mg/kg b.w. i.r.) and therapy influence in chronic experiments in female rats. Regularly, cysteamine colon lesions were markedly mitigated by ranitidine (10), omeprazole (10), atropine (10), methylprednisolone (1), sulphasalazine (50; mg/kg), pentadecapeptide BPC 157 (PL-10, PLD-116; 10 microg or 10 ng/kg). Specifically, after 1 or 3 months following initial challenge (cysteamine 400 mg/kg i.r.) in female rat, the therapy [BPC 157 (PL-10, PLD-116 (10.0 microg or 10.0 ng/kg; i.g., i.p., i.r.), ranitidine, omeprazole, atropine, methylprednisolone, sulphasalazine (i.p.)] reversed the protracted cysteamine colon injury: the 1 week-regimen (once daily application) started after 1 month post-cysteamine, as well as the 2 weeks-regimen (once daily application), which started after 3 months. The effect on recidive lesion was also tested. These cysteamine lesions may reappear after stopping therapy (after stopping therapy for 3 weeks at the end of 2-weeks regimen started in 3 months-cysteamine female rats) in sulphasalazine group, while this reappearance is markedly antagonized in pentadecapeptide BPC 157 (PL-10, PLD-116)-rats (cysteamine-colon lesion still substantially low). PMID:11595451

  5. Aldosterone and thyroid hormone interaction on the sodium and potassium transport pathways of rat colonic epithelium.

    PubMed

    Edmonds, C J; Willis, C L

    1990-01-01

    The effect of hypothyroidism on potassium adaptation (shown by increased potassium secretion in response to potassium loading) and on the action of aldosterone on potassium secretion and sodium fluxes was examined in the rat distal colon. Potassium adaptation, particularly the response to an acute potassium load, was impaired by hypothyroidism which also considerably reduced the rise of transepithelial electrical potential difference (p.d.) of total and transcellular (active) lumen-to-plasma sodium fluxes and of potassium secretion normally produced by aldosterone. These changes were, in part, corrected by a short period (3 days) of tri-iodothyronine replacement. Moreover in aldosterone-treated hypothyroid rats, amiloride in the lumen was considerably less effective in reducing the p.d. and sodium fluxes than in aldosterone-treated normal rats. The intracellular sodium transport pool was greater in the hypothyroid than in the normal rats (5.0 +/- 1.1 (S.E.M.) nmol/mg dry weight compared with 2.9 +/- 0.2 nmol/mg dry weight; P less than 0.02). Aldosterone increased the pool in the normal but not in the hypothyroid rats while amiloride had little effect on the pool in the aldosterone-treated hypothyroid rats but almost abolished it in aldosterone-treated normal rats. Aldosterone plays a major part in the adaptation of colonic sodium and potassium transport to sodium depletion or potassium excess; these adaptations were much impaired in hypothyroid animals. The present results are consistent with a deficiency in aldosterone induction of potassium- and amiloride-sensitive sodium pathways in the apical membrane of colonic epithelial cells in hypothyroid rats, a deficiency which limits the stimulant effect of aldosterone on sodium and potassium transport. PMID:2299278

  6. Effect of meat (beef, chicken, and bacon) on rat colon carcinogenesis

    PubMed Central

    Parnaud, Géraldine; Peiffer, Ginette; Taché, Sylviane; Corpet, Denis E.

    1998-01-01

    High intake of red meat or processed meat is associated with increased risk of colon cancer. In contrast, consumption of white meat (chicken) is not associated with risk and might even reduce the occurrence of colorectal cancer. We speculated that a diet containing beef or bacon would increase and a diet containing chicken would decrease colon carcinogenesis in rats. One hundred female Fischer 344 rats were given a single injection of azoxymethane (20 mg/kg i.p.), then randomized to 10 different AIN-76-based diets. Five diets were adjusted to 14% fat and 23% protein and five other diets to 28% fat and 40% protein. Fat and protein were supplied by 1) lard and casein, 2) olive oil and casein, 3) beef, 4) chicken with skin, and 5) bacon. Meat diets contained 30% or 60% freeze-dried fried meat. The diets were given ad libitum for 100 days, then colon tumor promotion was assessed by the multiplicity of aberrant crypt foci [number of crypts per aberrant crypt focus (ACF)]. The ACF multiplicity was nearly the same in all groups, except bacon-fed rats, with no effect of fat and protein level or source (p = 0.7 between 8 groups by analysis of variance). In contrast, compared with lard- and casein-fed controls, the ACF multiplicity was reduced by 12% in rats fed a diet with 30% bacon and by 20% in rats fed a diet with 60% bacon (p < 0.001). The water intake was higher in bacon-fed rats than in controls (p < 0.0001). The concentrations of iron and bile acids in fecal water and total fatty acids in feces changed with diet, but there was no correlation between these concentrations and the ACF multiplicity. Thus the hypothesis that colonic iron, bile acids, or total fatty acids can promote colon tumors is not supported by this study. The results suggest that, in rats, beef does not promote the growth of ACF and chicken does not protect against colon carcinogenesis. A bacon-based diet appears to protect against carcinogenesis, perhaps because bacon contains 5% NaCl and increased

  7. ATP-sensitive K(+) channels in rat colonic epithelium.

    PubMed

    Pouokam, Ervice; Bader, Sandra; Brück, Brigitta; Schmidt, Bärbel; Diener, Martin

    2013-06-01

    ATP-sensitive K(+) (KATP) channels couple the metabolic state of a cell to its electrical activity. They consist of a hetero-octameric complex with pore-forming Kir6.x (Kir6.1, Kir6.2) and regulatory sulfonylurea receptor (SUR) subunits. Functional data indicate that KATP channels contribute to epithelial K(+) currents at colonic epithelia. However, their molecular identity and their properties are largely unknown. Therefore, changes in short-circuit current (I sc) induced by the KATP channel opener pinacidil (5 10(-4) mol l(-1)) were measured in Ussing chambers under control conditions and in the presence of different blockers of KATP channels. The channel subunits expressed by the colonic epithelium were identified by immunohistochemistry and by RT-PCR. The K(+) channel opener, when administered at the serosal side, induced an increase in I sc consistent with the induction of transepithelial Cl(-) secretion after activation of basolateral K(+) channels, whereas mucosal administration of pinacidil resulted in a negative I sc. The increase in I sc evoked by serosal pinacidil was inhibited by serosal administration of glibenclamide (5 10(-4) mol l(-1)) and gliclazide (10(-6) mol l(-1)), but was resistant even against a high concentration (10(-2) mol l(-1)) of tolbutamide. In contrast, none of these inhibitors (administered at the mucosal side) reduced significantly the negative I sc induced by mucosal pinacidil. Instead, pinacidil inhibited Cl(-) currents across apical Cl(-) channels in basolaterally depolarized epithelia indicating that the negative I sc induced by mucosal pinacidil is due to a transient inhibition of Cl(-) secretion. In mRNA prepared from isolated colonic crypts, messenger RNA for both pore-forming subunits, Kir6.1 and Kir6.2, and two regulatory subunits (SUR1 and SUR2B) was found. Expression within the colonic epithelium was confirmed for these subunits by immunohistochemistry. In consequence, KATP channels are present in the basolateral membrane

  8. Negligible Colon Cancer Risk from Food-Borne Acrylamide Exposure in Male F344 Rats and Nude (nu/nu) Mice-Bearing Human Colon Tumor Xenografts

    PubMed Central

    Raju, Jayadev; Roberts, Jennifer; Sondagar, Chandni; Kapal, Kamla; Aziz, Syed A.; Caldwell, Don; Mehta, Rekha

    2013-01-01

    Acrylamide, a possible human carcinogen, is formed in certain carbohydrate-rich foods processed at high temperature. We evaluated if dietary acrylamide, at doses (0.5, 1.0 or 2.0 mg/kg diet) reflecting upper levels found in human foods, modulated colon tumorigenesis in two rodent models. Male F344 rats were randomized to receive diets without (control) or with acrylamide. 2-weeks later, rats in each group received two weekly subcutaneous injections of either azoxymethane (AOM) or saline, and were killed 20 weeks post-injections; colons were assessed for tumors. Male athymic nude (nu/nu) mice bearing HT-29 human colon adenocarcinoma cells-derived tumor xenografts received diets without (control) or with acrylamide; tumor growth was monitored and mice were killed 4 weeks later. In the F344 rat study, no tumors were found in the colons of the saline-injected rats. However, the colon tumor incidence was 54.2% and 66.7% in the control and the 2 mg/kg acrylamide-treated AOM-injected groups, respectively. While tumor multiplicity was similar across all diet groups, tumor size and burden were higher in the 2 mg/kg acrylamide group compared to the AOM control. These results suggest that acrylamide by itself is not a “complete carcinogen”, but acts as a “co-carcinogen” by exacerbating the effects of AOM. The nude mouse study indicated no differences in the growth of human colon tumor xenografts between acrylamide-treated and control mice, suggesting that acrylamide does not aid in the progression of established tumors. Hence, food-borne acrylamide at levels comparable to those found in human foods is neither an independent carcinogen nor a tumor promoter in the colon. However, our results characterize a potential hazard of acrylamide as a colon co-carcinogen in association with known and possibly other environmental tumor initiators/promoters. PMID:24040114

  9. The colonic response to genotoxic carcinogens in the rat: regulation by dietary fibre.

    PubMed

    Hu, Y; Martin, J; Le Leu, R; Young, G P

    2002-07-01

    The apoptotic response to DNA damage appears to be an innate biological mechanism for protection against tumourigenesis. It is possible that agents that protect against colorectal cancer act by enhancing the apoptotic deletion of cells suffering DNA damage, with consequent removal of those with tumourigenic mutations. We examined the acute apoptotic response to genotoxic carcinogens ("AARGC") in colonic epithelium and the possibility that dietary fibres of different fermentability might regulate AARGC. To fully define the time-course and nature of AARGC in response to the carcinogen azoxymethane (AOM), a single injection of AOM (10 mg/kg) was given to rats and apoptosis monitored in the colon by light microscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling staining over a 72 h period. Having defined the site and time of maximum response, two groups of eight rats were fed diets containing 10% wheat bran fibre (WB; fermentable) or 10% methylcellulose (MC; poorly fermentable) for 4 weeks. Colonic AARGC was compared by light microscopy; lumenal short chain fatty acids (SCFAs) and pH were measured as indicators of the fermentative environment. AOM-induced AARGC was maximal at 8 h and greater in distal compared with proximal colon. Apoptotic cells were situated predominantly in the lower half of the crypt, with the median at position 9 indicating involvement of daughter as well as stem cells. There was no "second wave" of apoptosis within 72 h as follows irradiation in small intestine. Distal colonic AARGC in rats fed WB was twice that in rats fed MC (P < 0.01). Compared with MC, WB significantly lowered lumenal pH and increased all SCFAs including butyrate, while proliferation did not differ between the fibres. Certainly, dietary fibres can regulate AARGC and further studies are warranted to determine if this biological effect is the way in which dietary factors regulate tumourigenesis. Lumenal generation of butyrate may enhance

  10. Alteration of enteric monoamines with monoamine receptors and colonic dysmotility in 6-hydroxydopamine-induced Parkinson's disease rats.

    PubMed

    Zhang, Xiaoli; Li, Yun; Liu, Chenzhe; Fan, Ruifang; Wang, Ping; Zheng, Lifei; Hong, Feng; Feng, Xiaoyan; Zhang, Yue; Li, Lisheng; Zhu, Jinxia

    2015-08-01

    Constipation is common in Parkinson's disease (PD), in which monoamines (dopamine [DA], norepinephrine [NE], and 5-hydroxytryptamine [5-HT]) play an important role. Rats microinjected with 6-hydroxydopamine (6-OHDA) into the bilateral substantia nigra (SN) exhibit constipation, but the role of monoamines and their receptors is not clear. In the present study, colonic motility, monoamine content, and the expression of monoamine receptors were examined using strain gauge force transducers, ultraperformance liquid chromatography tandem mass spectrometry, immunofluorescence, and Western blot. The 6-OHDA rats displayed a significant reduction in dopaminergic neurons in the SN and a decreased time on rota-rod test and a marked decrease in daily fecal production and fecal water content. The amplitude of colonic spontaneous contraction was obviously decreased in 6-OHDA rats. Blocking D1-like receptor and β3-adrenoceptor (β3-AR) significantly reduced the inhibition of DA and NE on the colonic motility, respectively, whereas the 5-HT and 5-HT4 receptor agonists promoted the colonic motility. Moreover, DA content was increased in the colonic muscularis externa of 6-OHDA rats. The protein expression of β3-ARs was notably upregulated, but 5-HT4 receptors were significantly decreased in the colonic muscularis externa of 6-OHDA rats. We conclude that enhanced DA and β3-ARs and decreased 5-HT4 receptors may be contributed to the colonic dysmotility and constipation observed in 6-OHDA rats. PMID:25766133

  11. Characteristics of submucosal lymphoid tissue located in the proximal colon of the rat.

    PubMed Central

    Crouse, D A; Perry, G A; Murphy, B O; Sharp, J G

    1989-01-01

    In this study we have examined the morphology and steroid sensitivity of proximal colonic lymphoid tissue in the Fisher 344 rat. A time course study was conducted in which groups of animals were injected subcutaneously with hydrocortisone sodium succinate (125 mg/kg body weight) and killed on Days 0-4. Thymus, jejunal and ileal Peyer's patches and proximal colonic lymphoid tissue were excised, weighed and processed for histological analysis. The results showed that the maximum cytoreductive effects of the hydrocortisone were evident on Day 2. Thymus and proximal colonic lymphoid tissue weight decreased to 5 and 18% of the control values respectively, before returning towards control values over the next two days. In contrast, jejunal and ileal Peyer's patch weights were unaltered. A dose response experiment was conducted using the same endpoints. Rats were injected subcutaneously with hydrocortisone at 60, 120, 200 and 300 mg/kg body weight and killed on Day 2. The results of this experiment showed that the proximal colonic lymphoid tissue, like thymus, responded with a dose-dependent loss of tissue weight. The spleen and Peyer's patches showed only a slight weight decrease compared to the control. These data showed that the response of proximal colonic lymphoid tissue to steroids was more similar to that of thymus, a primary lymphoid tissue, than to other secondary lymphoid tissues. Finally, grafts of fetal proximal colon under the kidney capsule of syngeneic adults supported the development of this lymphoid aggregate in the absence of luminal antigenic stimulation. These results suggest that the development and functional contribution of proximal colonic lymphoid tissue to the immune system warrants a more detailed examination. Images Fig. 2 Fig. 3 Fig. 5 Fig. 6 PMID:2808123

  12. A Simple, Quantitative Method Using Alginate Gel to Determine Rat Colonic Tumor Volume In Vivo

    PubMed Central

    Irving, Amy A; Young, Lindsay B; Pleiman, Jennifer K; Konrath, Michael J; Marzella, Blake; Nonte, Michael; Cacciatore, Justin; Ford, Madeline R; Clipson, Linda; Amos-Landgraf, James M; Dove, William F

    2014-01-01

    Many studies of the response of colonic tumors to therapeutics use tumor multiplicity as the endpoint to determine the effectiveness of the agent. These studies can be greatly enhanced by accurate measurements of tumor volume. Here we present a quantitative method to easily and accurately determine colonic tumor volume. This approach uses a biocompatible alginate to create a negative mold of a tumor-bearing colon; this mold is then used to make positive casts of dental stone that replicate the shape of each original tumor. The weight of the dental stone cast correlates highly with the weight of the dissected tumors. After refinement of the technique, overall error in tumor volume was 16.9% ± 7.9% and includes error from both the alginate and dental stone procedures. Because this technique is limited to molding of tumors in the colon, we utilized the ApcPirc/+ rat, which has a propensity for developing colonic tumors that reflect the location of the majority of human intestinal tumors. We have successfully used the described method to determine tumor volumes ranging from 4 to 196 mm3. Alginate molding combined with dental stone casting is a facile method for determining tumor volume in vivo without costly equipment or knowledge of analytic software. This broadly accessible method creates the opportunity to objectively study colonic tumors over time in living animals in conjunction with other experiments and without transferring animals from the facility where they are maintained. PMID:24674588

  13. Salicylate modulates oxidative stress in the rat colon: a proteomic approach.

    PubMed

    Drew, Janice E; Padidar, Sara; Horgan, Graham; Duthie, Garry G; Russell, Wendy R; Reid, Martin; Duncan, Gary; Rucklidge, Garry J

    2006-07-14

    The dietary phenolic compound, salicylic acid, decreases oxidative stress and pro-inflammatory and potentially neo-plastic prostaglandins with a concomitant increase in glutathione peroxidase activity. Salicylic acid, a dietary plant-based phenolic compound and also the main metabolite of aspirin, may contribute to the colon protective effects of plant-based diets. Oxidative stress is a characteristic of pre-cancerous and cancerous colon and inflammatory bowel diseases (IBD) that increase colon cancer risk. The mechanism(s) whereby salicylic acid modulates potentially pro-cancerous activity associated with oxidative stress is further investigated here using a proteomic approach. A rat model of oxidative stress was supplemented with salicylic acid (1 mg/kg diet, mean plasma levels 310+/-32 micromol/l). Soluble colon protein extracts were subjected to 2D PAGE. Salicylic acid modulated proteins, identified using MALDI-TOF and LC/MS/MS, are involved in protein folding, transport, redox, energy metabolism and cytoskeletal regulation. A partial least squares (PLS) analysis approach was used to assist biological interpretation of the altered protein profiles via their associations between previously published biochemical measurements of oxidative stress, prostaglandin levels and increased glutathione peroxidase activity. Early detection of altered homeostasis in colon may assist in identifying pre-pathological features preceding colon tumorigenesis and contribute to an understanding of epidemiological evidence supporting a protective effect of plant-based diets. PMID:16730665

  14. Neonatal Cystitis-Induced Colonic Hypersensitivity in Adult Rats: A Model of Viscero-Visceral Convergence

    PubMed Central

    Miranda, Adrian; Mickle, Aaron; Schmidt, Jamie; Zhang, Zhihong; Shaker, Reza; Banerjee, Banani; Sengupta, Jyoti N.

    2011-01-01

    Background The objective of this study was to determine if neonatal cystitis alters colonic sensitivity later in life and to investigate the role of peripheral mechanisms. Methods Neonatal rats received intravesical zymosan, normal saline, or anesthesia only for three consecutive days (postnatal days 14th–16th). The estrous cycle phase was determined prior to recording the visceromotor response (VMR) to colorectal distension (CRD) in adult rats. Eosinophils and mast cells were examined from colon and bladder tissue. CRD or urinary bladder distension (UBD)-sensitive pelvic nerve afferents (PNAs) were identified and their responses to distension were examined. The relative expression of N-methyl-D-aspartic acid (NMDA) NR1 subunit in the L6-S1 spinal cord was examined using Western blot. Results The VMR to CRD (≥10mmHg) in the neonatal zymosan group was significantly higher than control in both the diestrus, estrus phase and in all phases combined. There was no difference in the total number of eosinophils, mast cells or number of degranulated mast cells between groups. The spontaneous firing of UBD, but not CRD-sensitive PNAs from the zymosan rats was significantly higher than the control. However, the mechanosensitive properties of PNAs to CRD or UBD were no different between groups (p > 0.05). The expression of spinal NR1 subunit was significantly higher in zymosan-treated rats compared to saline treated rats (p <0.05). Conclusion Neonatal cystitis results in colonic hypersensitivity in adult rats without changing tissue histology or the mechanosensitive properties of CRD-sensitive PNAs. Neonatal cystitis does results in overexpression of spinal NR1 subunit in adult rats. PMID:21592255

  15. A loop resonator for slice-selective in vivo EPR imaging in rats.

    PubMed

    Hirata, Hiroshi; He, Guanglong; Deng, Yuanmu; Salikhov, Ildar; Petryakov, Sergey; Zweier, Jay L

    2008-01-01

    A loop resonator was developed for 300 MHz continuous-wave electron paramagnetic resonance (CW-EPR) spectroscopy and imaging in live rats. A single-turn loop (55 mm in diameter) was used to provide sufficient space for the rat body. Efficiency for generating a radiofrequency magnetic field of 38 microT/W(1/2) was achieved at the center of the loop. For the resonator itself, an unloaded quality factor of 430 was obtained. When a 350 g rat was placed in the resonator at the level of the lower abdomen, the quality factor decreased to 18. The sensitive volume in the loop was visualized with a bottle filled with an aqueous solution of the nitroxide spin probe 3-carbamoyl-2,2,5,5-tetramethyl-3-pyrrolin-1-yloxy (3-CP). The resonator was shown to enable EPR imaging in live rats. Imaging was performed for 3-CP that had been infused intravenously into the rat and its distribution was visualized within the lower abdomen. PMID:18006343

  16. The function of 5-HT3 receptors on colonic transit in rats.

    PubMed

    Haga, K; Asano, K; Fukuda, T; Kobayakawa, T

    1995-12-01

    The function of serotonin (5-HT)3 receptors on colonic transit was investigated in unanesthetized rats. The colonic transit was accelerated by 5-HT (10 mg/kg, s.c.), 2-methyl-5-HT (30 mg/kg, s.c.), neostigmine (0.03-0.1 mg/kg, s.c.), corticotropin releasing factor (CRF; 1 microgram intracerebroventricular administration) and restraint stress (for 45 minutes). A potent and selective 5-HT3 receptor antagonist, azasetron (+/-)-N-(1-azabicyclo[2.2.2]oct-3-yl)-6-chloro- 4-methyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-8-carboxamide monohydrochloride ; 0.01-10 mg/kg, p.o. inhibited the 5-HT-, CRF- and stress-accelerated colonic transit in a dose-dependent manner. Ondansetron (10 mg/kg, p.o.) and granisetron (1 mg/kg, p.o) also inhibited the stress-accelerated colonic transit, but azasetron was more effective than these two drugs. Atropine methylbromide (0.1 mg/kg, s.c.) and tetrodotoxin (0.01 mg/kg, s.c.) inhibited the accelerated colonic transit under stress conditions, but methysergide (10 mg/kg, s.c.), SDZ205-557 (10 mg/kg, s.c.), domperidone (30 mg/kg, p.o.), trimebutine (300 mg/kg, p.o.), did not. Azasetron (10 micrograms) administered intracerebroventricularly did not inhibit the stress-induced acceleration. These results suggest that endogenous 5-HT which is released through stress accelerates the colonic transit via the 5-HT3 receptors and finally a cholinergic mechanism. It is considered that azasetron inhibits colonic transit particularly under stress conditions through the blockade of the peripheral 5-HT3 receptors. Azasetron may improve bowel function in stress-related colonic dysfunction like irritable bowel syndrome. PMID:8653566

  17. Architecture of kangaroo rat inner medulla: segmentation of descending thin limb of Henle's loop.

    PubMed

    Urity, Vinoo B; Issaian, Tadeh; Braun, Eldon J; Dantzler, William H; Pannabecker, Thomas L

    2012-03-15

    We hypothesize that the inner medulla of the kangaroo rat Dipodomys merriami, a desert rodent that concentrates its urine to more than 6,000 mosmol/kgH(2)O water, provides unique examples of architectural features necessary for production of highly concentrated urine. To investigate this architecture, inner medullary nephron segments in the initial 3,000 μm below the outer medulla were assessed with digital reconstructions from physical tissue sections. Descending thin limbs of Henle (DTLs), ascending thin limbs of Henle (ATLs), and collecting ducts (CDs) were identified by immunofluorescence using antibodies that label segment-specific proteins associated with transepithelial water flux (aquaporin 1 and 2, AQP1 and AQP2) and chloride flux (the chloride channel ClC-K1); all tubules and vessels were labeled with wheat germ agglutinin. In the outer 3,000 μm of the inner medulla, AQP1-positive DTLs lie at the periphery of groups of CDs. ATLs lie inside and outside the groups of CDs. Immunohistochemistry and reconstructions of loops that form their bends in the outer 3,000 μm of the inner medulla show that, relative to loop length, the AQP1-positive segment of the kangaroo rat is significantly longer than that of the Munich-Wistar rat. The length of ClC-K1 expression in the prebend region at the terminal end of the descending side of the loop in kangaroo rat is about 50% shorter than that of the Munich-Wistar rat. Tubular fluid of the kangaroo rat DTL may approach osmotic equilibrium with interstitial fluid by water reabsorption along a relatively longer tubule length, compared with Munich-Wistar rat. A relatively shorter-length prebend segment may promote a steeper reabsorptive driving force at the loop bend. These structural features predict functionality that is potentially significant in the production of a high urine osmolality in the kangaroo rat. PMID:22237592

  18. Fluid reabsorption in Henle's loop and urinary excretion of sodium and water in normal rats and rats with chronic hypertension

    PubMed Central

    Stumpe, Klaus O.; Lowitz, Hans D.; Ochwadt, Bruno

    1970-01-01

    The function of the short loops of Henle was investigated by micropuncture technique in normal rats, in rats with spontaneous hypertension, and in the untouched kidney of rats with experimental renal hypertension. All animals received a standard infusion of 1.2 ml of isotonic saline per hr. With increasing arterial blood pressure (range from 90 to 220 mm Hg), a continuous decrease in transit time of Lissamine green through Henle's loop from 32 to 10 sec was observed. Fractional water reabsorption along the loop declined progressively from 26 to 10%, and fractional sodium reabsorption decreased from 40 to 36% of the filtered load. The fluid volume in Henle's loop calculated from transit time and mean flow rate also decreased with increasing blood pressure. There was no change in superficial single nephron filtration rate but there was a slight increase in total glomerular filtration rate (GFR). Sodium and water reabsorption in the proximal tubule remained unchanged. Urine flow rate, sodium excretion, osmolar clearance, and negative free water clearance increased with increasing blood pressure. The osmolal urine to plasma (U/P) ratio declined but did not fall below a value of 1.5. It is concluded that the increase in sodium and water excretion with chronic elevation of arterial blood pressure is caused by a decrease of sodium and water reabsorption along the loop of Henle, presumably as a consequence of increased medullary blood pressure. PMID:5422022

  19. THE INDUCTION OF ABERRANT CRYPT FOCI (ACF) IN THE COLONS OF RATS BY TRIHALOMETHANES ADMINISTERED IN THE DRINKING WATER

    EPA Science Inventory

    Bromodichloromethane (BDCM) and bromoform (TBM) had been demonstrated to be colon carcinogens in male and female F344/N rats following administration by corn oil gavage. Our chronic bioassay of BDCM administered in the drinking water failed to demonstrate an enhanced colon cance...

  20. Chemopreventive effect of zingerone against colon carcinogenesis induced by 1,2-dimethylhydrazine in rats.

    PubMed

    Vinothkumar, Rajenderan; Vinothkumar, Rajamanickam; Sudha, Mani; Nalini, Namasivayam

    2014-09-01

    Zingerone [4-(4-hydroxy-3-methoxyphenyl)-2-butane], one of the active phenolic components isolated from Zingiber officinale, has antioxidant and anticarcinogenic properties. In our study, we have evaluated the effect of different doses of zingerone on lipid peroxidation (thiobarbituric acid-reactive substances, lipid hydroxyl radical and conjugated dienes), tissue enzymatic antioxidants (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase), and nonenzymatic antioxidants (reduced glutathione, vitamin E, vitamin C), and also the formation of aberrant crypt foci (ACF) in male albino Wistar rats with colon cancer induced using 1,2-dimethylhydrazine (DMH). The rats were divided into six groups. Group 1 served as a control group and received a modified pellet diet; the rats in group 2 received a modified pellet diet along with zingerone (40 mg/kg b.w., orally every day); groups 3-6 were administered DMH (20 mg/kg b.w., subcutaneously) once a week for the first 4 weeks; and groups 4-6 received zingerone at three different doses of 10, 20 and 40 mg/kg b.w., respectively, every day for 16 weeks. Increased tumour incidence and ACF formation were accompanied by a decrease in the tissue lipid peroxidation, enzymatic and nonenzymatic antioxidant activities observed in the colon of DMH-treated rats. Supplementation with zingerone in DMH-treated rats led to a significant decrease in the tumour incidence and ACF formation with simultaneous modulation in the level of tissue lipid peroxidation and antioxidant status. Thus, in conclusion, we can suggest that zingerone effectively inhibits DMH-induced colon carcinogenesis in male Wistar rats. PMID:23903760

  1. Dietary modulation of rat colonic cAMP-dependent protein kinase activity.

    PubMed

    Aukema, H M; Davidson, L A; Chang, W C; Lupton, J R; Derr, J N; Chapkin, R S

    1994-10-20

    Malignant transformation of cells is associated with enhanced proliferation and alterations in cAMP-dependent protein kinase (PKA) activity. To investigate the role of PKA in normal colonic cell proliferation, PKA was characterized in rat colonic mucosa. In addition, rats were fed diets containing different fats (corn oil, fish oil) and fibers (pectin, cellulose, fiber free) to elicit varying levels of colonic cell proliferation in order to study this signaling system under normal physiologic conditions. Overall, PKA activities were higher in cytosolic compared to membrane fractions. PKA type II (PKA II) isozyme contributed 89 +/- 1% and 96 +/- 1% of total PKA activity in cytosolic and membrane fractions, respectively. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis revealed the presence of mRNA for both the alpha and beta isoforms of the regulatory subunits of PKA II. PKA activities were 21-33% higher in distal membrane and total distal fractions in rats fed a cellulose/corn oil diet compared to animals consuming the other fiber/fat diets. These effects were seen only in the distal colon, where the number of cells per crypt column was elevated only in animals fed the cellulose/corn oil diet relative to other diets. Diet-induced mitogenic responses did not involve significant changes in the relative activity of PKA I and II isozymes. These data demonstrate that dietary effects on PKA activity in the distal colon may be related to changes in cell differentiation as indicated by the number of cells per crypt column. PMID:7948042

  2. Neurochemical features of endomorphin-2-containing neurons in the submucosal plexus of the rat colon

    PubMed Central

    Li, Jun-Ping; Zhang, Ting; Gao, Chang-Jun; Kou, Zhen-Zhen; Jiao, Xu-Wen; Zhang, Lian-Xiang; Wu, Zhen-Yu; He, Zhong-Yi; Li, Yun-Qing

    2015-01-01

    AIM: To investigate the distribution and neurochemical phenotype of endomorphin-2 (EM-2)-containing neurons in the submucosal plexus of the rat colon. METHODS: The mid-colons between the right and left flexures were removed from rats, and transferred into Kreb’s solution. For whole-mount preparations, the mucosal, outer longitudinal muscle and inner circular muscle layers of the tissues were separated from the submucosal layer attached to the submucosal plexus. The whole-mount preparations from each rat mid-colon were mounted onto seven gelatin-coated glass slides, and processed for immunofluorescence histochemical double-staining of EM-2 with calcitonin gene-related peptide (CGRP), choline acetyltransferase (ChAT), nitric oxide synthetase (NOS), neuron-specific enolase (NSE), substance P (SP) and vasoactive intestinal peptide (VIP). After staining, all the fluorescence-labeled sections were observed with a confocal laser scanning microscope. To estimate the extent of the co-localization of EM-2 with CGRP, ChAT, NOS, NSE, SP and VIP, ganglia, which have a clear boundary and neuronal cell outline, were randomly selected from each specimen for this analysis. RESULTS: In the submucosal plexus of the mid-colon, many EM-2-immunoreactive (IR) and NSE-IR neuronal cell bodies were found in the submucosal plexus of the rat mid-colon. Approximately 6 ± 4.2 EM-2-IR neurons aggregated within each ganglion and a few EM-2-IR neurons were also found outside the ganglia. The EM-2-IR neurons were also immunopositive for ChAT, SP, VIP or NOS. EM-2-IR nerve fibers coursed near ChAT-IR neurons, and some of these fibers were even distributed around ChAT-IR neuronal cell bodies. Some EM-2-IR neuronal cell bodies were surrounded by SP-IR nerve fibers, but many long processes connecting adjacent ganglia were negative for EM-2 immunostaining. Long VIP-IR processes with many branches coursed through the ganglia and surrounded the EM-2-IR neurons. The percentages of the EM-2-IR neurons

  3. Influence of feeding regimens on rat gut fluids and colonic metabolism of diclofenac-β-cyclodextrin.

    PubMed

    Vieira, Amélia C F; Murdan, Sudaxshina; Serra, Arménio C; Veiga, Francisco J; Gonsalves, António M d'A Rocha; Basit, Abdul W

    2014-11-01

    Feeding states may affect the performance of colonic prodrugs. The aim is to investigate the influence of feeding regimen in Wistar rats on: (i) distribution and pH contents along the gut and (ii) metabolism of two colonic prodrugs, diclofenac-β-cyclodextrin and a commercially available control, sulfasalazine, within the caecal and colonic contents. Male Wistar rats were subject to four different feeding regimens, the gut contents characterized (mass and pH) and the metabolism of prodrugs investigated. The feeding regimen affects gut contents (mass and pH), more specifically in the stomach and lower intestine, and affects the rate of metabolism of diclofenac-β-cyclodextrin, but not that of sulfasalazine. The latter's degradation is much faster than that of diclofenac-β-cyclodextrin while the metabolism of both prodrugs is faster in colonic (versus caecal) contents. Fasting results in most rapid degradation of diclofenac-β-cyclodextrin, possibly due to lack of competition (absence of food) for microbial enzymatic activity. PMID:25129806

  4. Huqi San-Evoked Rat Colonic Anion Secretion through Increasing CFTR Expression

    PubMed Central

    Xue, Xiaowei; Shi, Zhengming; Wang, Wen; Yu, Xiaotong; Feng, Ping; Zhang, Min; Wang, Xuejiang; Xu, Jingdong

    2015-01-01

    Huqi San (HQS) is a Chinese herbal preparation of eight medicinal herbs that promote diuresis, detoxification, blood circulation, and cholestasis. Defects in transporter expression and function can cause cholestasis and jaundice. However, the mechanism of the cholestasis underlying HQS effects, especially on the gastrointestinal tract ion secretion, has not been elucidated. Real-time RT-PCR and Western blotting were used to study the expression and localization of cystic fibrosis transmembrane conductance regulator (CFTR) and α-ENaC in rat alimentary tract, and then the effect of HQS on the ion transport in rat distal colon mucosa was investigated using the short-circuit current (ISC) technique. The results showed that pretreatment with HQS significantly enhanced mRNA transcripts and protein content of CFTR in liver and distal colon but not α-ENaC in alimentary organs. HQS increases ISC and decreases the transepithelial resistance. Pretreatment with epithelial Na+ channel blocker did not affect the ISC responses elicited by HQS, but removal of extracellular Cl− or pretreatment with Cl− channel or Na+-K+-2Cl− cotransporter blocker inhibited HQS-elicited ISC responses. These findings demonstrated that HQS, RA, and RP can stimulate Cl− secretion in the distal colon by increasing the mRNA transcripts and protein content of CFTR in liver and distal colon. PMID:26290673

  5. Effects of pinaverium bromide and verapamil on the motility of the rat isolated colon.

    PubMed

    Baumgartner, A; Drack, E; Halter, F; Scheurer, U

    1985-09-01

    Pinaverium bromide was 30 times less potent than verapamil in inhibiting intraluminal pressure responses of in vitro rat colonic segments to barium chloride, acetylcholine, FK 33-824 or field stimulation. The inhibitory effects of both verapamil and pinaverium bromide on the pressure responses to field stimulation were antagonized similarly by exogenous calcium administration. These results support the concept that pinaverium bromide acts on calcium channels in the smooth muscle cell membrane. PMID:4052731

  6. Effects of pinaverium bromide and verapamil on the motility of the rat isolated colon.

    PubMed Central

    Baumgartner, A.; Drack, E.; Halter, F.; Scheurer, U.

    1985-01-01

    Pinaverium bromide was 30 times less potent than verapamil in inhibiting intraluminal pressure responses of in vitro rat colonic segments to barium chloride, acetylcholine, FK 33-824 or field stimulation. The inhibitory effects of both verapamil and pinaverium bromide on the pressure responses to field stimulation were antagonized similarly by exogenous calcium administration. These results support the concept that pinaverium bromide acts on calcium channels in the smooth muscle cell membrane. PMID:4052731

  7. Luteolin supplementation adjacent to aspirin treatment reduced dimethylhydrazine-induced experimental colon carcinogenesis in rats.

    PubMed

    Osman, Neamt H A; Said, Usama Z; El-Waseef, Ahmed M; Ahmed, Esraa S A

    2015-02-01

    Previous studies have shown that aspirin is used in colon cancer treatment. However, long-term of Aspirin usage is limited to gastric and renal toxicity. Luteolin (LUT) has cancer prevention and anti-inflammatory effects. The present study was designed to investigate the effect of LUT supplementation and Aspirin treatment in dimethylhydrazine (DMH)-induced carcinogenesis in rats. DMH (20 mg/kg BW/week) treated rats received gavages with Aspirin (50 mg/kg BW/week) and LUT (0.2 mg/kg BW/day) for 15 weeks. DMH injections induce colon polyps and renal bleeding, significantly increasing carcinoembryonic antigen (CEA), cyclooxygenase-2 (COX-2), oxidative stress, and kidney function tests and reducing antioxidant markers. Either Aspirin or LUT gavages alone or combined produce a significant decrease in colon polyp number and size, significantly decreasing CEA, COX-2, and oxidative stress and increasing antioxidant markers. In conclusion, the supplementations of LUT adjacent to Aspirin in the treatment of DMH-induced carcinogenesis in rats reflect a better effect than the use of Aspirin alone. PMID:25342594

  8. Protective effect ofAgave salmiana fructans in azoxymethane- induced colon cancer in Wistar rats.

    PubMed

    Dávila-Céspedes, Antonio; Juárez-Flores, Bertha I; Pinos-Rodríguezc, Juan M; Aguirre-Riverab, Juan R; Oros-Ovalled, A Cuahutemoc; Loyola-Martínez, E D; Andrade-Zaldívar, Hera

    2014-10-01

    Colon cancer is a world concerning disease; it shows a high mortality rate and may be related to eating habits. Studies using inulin-like fructans, which are produced as energy supplies by several plants, have demonstrated a chemo-protective effect of these fructans in colon cancer. However, agavins a structurally different type of fructans from the Agave genus with demonstrated prebiotic effects, have been poorly studied for their possible protective effects in cancer. The aim of the present study was to evaluate the effect ofAgave fructan-rich diets in colon cancer progress using a rat model and "Agave mezcalero potosino" A. salmiana Otto ex Salm Dick, which is widely distributed in Mexico. Results showed a significant decrease (p<0.05) in early lesions of colon cancer (aberrant crypt foci) compared with the control group. These data suggest that fructans from A. salmiana may contribute to a reduction in the risk of colon cancer as well as inulin-like compounds. PMID:25522547

  9. Prevention of precancerous colonic lesions in rats by soy flakes, soy flour, genistein, and calcium.

    PubMed

    Thiagarajan, D G; Bennink, M R; Bourquin, L D; Kavas, F A

    1998-12-01

    The main purpose of this research was to determine whether diets containing soy products would inhibit the early stages of azoxymethane-induced colon cancer in F344 rats. Additional objectives were to determine whether feeding starch instead of sucrose, feeding additional calcium (0.5% compared with 0.1%), or feeding a low-fiber powdered enteral formula would influence early colon carcinogenesis. Colon cancer was initiated with 2 injections of azoxymethane (15 mg/kg body wt) and a 12-wk dietary treatment period was started 1 wk after the second injection. Precancerous colon lesions were assessed as foci with aberrant crypts (FAC). The mean numbers of FAC were 133 [soy concentrate (low concentration of phytochemicals)], 111 (starch substituted for sucrose), 98 [full-fat soy flakes (whole soybeans)], 87 (defatted soy flour), 77 (0.015% genistein), and 70 (0.5% Ca). The soy flour and full-fat soy flake diets contained 0.049% genistein derivatives (primarily glycosides), but were less effective in inhibiting the formation of FAC than the diet containing 0.015% genistein (as the aglycone). Eating soybeans and soy flour may reduce the early stages of colon cancer. PMID:9848506

  10. Tomato and garlic can modulate azoxymethane-induced colon carcinogenesis in rats.

    PubMed

    Sengupta, A; Ghosh, S; Das, S

    2003-06-01

    Tomato (Lycopersicon esculentum) and garlic (Allium cepa) are important constituents of the human diet. Compounds like diallyl sulfides, diallyl disulfides and quercetin, which are active components of garlic, have known anti-inflammatory, antimutagenic activities. Similarly, active components in tomato, such as kaempferol and chlorogenic acid, have antimutagenic activities and lycopene is the most active oxygen quencher with potential chemopreventive activities. In view of this, an endeavour was made to evaluate the anticarcinogenic effect, if any, of tomato and garlic consumption individually and in combination on azoxymethane-induced colonic precancerous lesion, the aberrant crypt foci in animal model. Sprague-Dawley rats (4-5 weeks old) were injected with azoxymethane (15 mg/kg b.w.) and orally administered with 2% (w/v) of tomato, garlic and a combination of both. After 12 weeks of first azoxymethane injection, colons were assessed for aberrant crypt foci and compared with the carcinogen control group. Lipid peroxidation level and glutathione-S-transferase (GST) activity were assessed in liver as well as in colon. Furthermore, in situ cell proliferation and apoptosis were estimated using the Brdu incorporation method and TUNEL method respectively. It was observed that aberrant crypt foci were reduced in all treated groups (by 32.11% in garlic, by 76.14% in tomato and by 55.96% in the combination group). Among treated groups, GST activity was found to be induced in both liver and colon, whereas considerable reduction in lipid peroxidation level was observed in liver as well as in colon with respect to the carcinogen control group. Significant reduction in Brdu labelling index and increase in apoptotic index in colon was noted in the treated groups. These results suggest that tomato and garlic suspensions have a protective effect on colon carcinogenesis, which is mediated by modulation of different biological pathways during carcinogenesis. PMID:12771557

  11. Lack of efficacy of blueberry in nutritional prevention of azoxymethane-initiated cancers of rat small intestine and colon

    PubMed Central

    2009-01-01

    Background Blueberries may lower relative risk for cancers of the gastrointestinal tract. Previous work indicated an inhibitory effect of consumed blueberry (BB) on formation of aberrant crypt foci (ACF) in colons of male Fisher F344 rats (inbred strain). However, effects of BB on colon tumors and in both genders are unknown. Methods We examined efficacy of BB in inhibition of azoxymethane (AOM)-induced colon ACF and intestine tumors in male and female Sprague-Dawley rats (outbred strain). Pregnant rats were fed a diet with or without 10% BB powder; progeny were weaned to the same diet as their dam and received AOM as young adults. Results Male and female rats on control diet had similar numbers of ACF at 6 weeks after AOM administration. BB increased (P < 0.05) ACF numbers within the distal colon of female but not male rats. There was a significant (P < 0.05) diet by gender interaction with respect to total colon ACF number. Colon and duodenum tumor incidences were less in females than males at 17 weeks after AOM. BB tended (0.1 > P > 0.05) to reduce overall gastrointestinal tract tumor incidence in males, however, tumor incidence in females was unaffected (P > 0.1) by BB. There was a tendency (0.1 > P > 0.05) for fewer adenocarcinomas (relative to total of adenomatous polyps plus adenocarcinomas) in colons of female than male tumor-bearing rats; in small intestine, this gender difference was significant (P < 0.05). BB favored (P < 0.05) fewer adenocarcinomas and more adenomatous polyps (as a proportion of total tumor number) in female rat small intestine. Conclusion Results did not indicate robust cancer-preventive effects of BB. Blueberry influenced ACF occurrence in distal colon and tumor progression in duodenum, in gender-specific fashion. Data indicate the potential for slowing tumor progression (adenomatous polyp to adenocarcinoma) by BB. PMID:19758446

  12. Diets enriched with cereal brans or inulin modulate protein kinase C activity and isozyme expression in rat colonic mucosa.

    PubMed

    Pajari, A M; Oikarinen, S; Gråsten, S; Mutanen, M

    2000-11-01

    The role of dietary fibres in colon carcinogenesis is controversial. To elucidate the mechanisms by which different dietary fibre sources may affect colonic tumour development, we studied the effects of diets enriched with cereal brans or inulin on protein kinase C (PKC) activity and isozyme expression in rat colon. Male Wistar rats (twelve per group) were fed one of the following AIN-93G-based diets (Reeves et al. 1993) for 4 weeks: a non-fibre high-fat diet or one of the four high-fat diets supplemented with either rye, oat or wheat bran or inulin at 100 g/kg diet. The fat concentration (20 g/100 g) and fatty acid composition of the non-fibre high-fat diet was designed to approximate that in a typical Western-type diet. In the proximal colon, rats fed the inulin diet had a significantly higher membrane PKC activity and a higher membrane PKC delta level than rats fed the non-fibre diet In the distal colon, rats fed the inulin and oat bran diets had a higher total PKC activity and a higher membrane PKC beta 2 level than rats fed the wheat-bran diet. Rats in the non-fibre and wheat-bran groups had the lowest concentrations of luminal diacylglycerol. In conclusion, feeding of wheat bran resulted in low distal PKC activity and expression of PKC beta 2, a PKC isozyme related to colonic cell proliferation and increased susceptibility for colon carcinogenesis, which may explain in part the protective effect of wheat bran against tumour development in a number of experimental colon cancer studies. The increase in PKC activity and PKC beta 2 expression by feeding inulin may be a drawback of inulin as a functional food. PMID:11177176

  13. Mechanisms involved in carbachol-induced Ca2+ sensitization of contractile elements in rat proximal and distal colon

    PubMed Central

    Takeuchi, Tadayoshi; Kushida, Masahiko; Hirayama, Nobue; Kitayama, Muneyoshi; Fujita, Akikazu; Hata, Fumiaki

    2004-01-01

    Mechanisms involved in Ca2+ sensitization of contractile elements induced by the activation of muscarinic receptors in membrane-permeabilized preparations of the rat proximal and distal colon were studied. In α-toxin-permeabilized preparations from the rat proximal and distal colon, Ca2+ induced a rapid phasic and subsequent tonic component. After Ca2+-induced contraction reached a plateau, guanosine 5′-triphosphate (GTP) and carbachol (CCh) in the presence of GTP further contracted preparations of both the proximal and distal colon (Ca2+ sensitization). Y-27632, a rho-kinase inhibitor, inhibited GTP plus CCh-induced Ca2+ sensitization more significantly in the proximal colon than in the distal colon. Y-27632 at 10 μM had no effect on Ca2+-induced contraction or slightly inhibited phorbol-12,13-dibutyrate-induced Ca2+ sensitization in either proximal or distal colon. Chelerythrine, a protein kinase C inhibitor, inhibited GTP plus CCh-induced Ca2+ sensitization in the distal colon, but not in the proximal colon. The component of Ca2+ sensitization that persisted after the chelerythrine treatment was completely inhibited by Y-27632. In β-escin-permeabilized preparations of the proximal colon, C3 exoenzyme completely inhibited GTP plus CCh-induced Ca2+ sensitization, but PKC(19–31) did not. In the distal colon, C3 exoenzyme abolished GTP-induced Ca2+ sensitization. It inhibited CCh-induced sensitization by 50 % and the remaining component was inhibited by PKC(19–31). These results suggest that both protein kinase C and rho pathways in parallel mediate the Ca2+ sensitization coupled to activation of muscarinic receptors in the rat distal colon, whereas the rho pathway alone mediates this action in the proximal colon. PMID:15159278

  14. Egg yolk proteins suppress azoxymethane-induced aberrant crypt foci formation and cell proliferation in the colon of rats.

    PubMed

    Ishikawa, Shin-Ichi; Asano, Takayuki; Takenoshita, Shingo; Nozawa, Yuuya; Arihara, Keizo; Itoh, Makoto

    2009-01-01

    Dietary proteins can influence colonic carcinogenesis; some proteins have a promotional effect, whereas others exhibit a preventive effect. Dietary egg yolk proteins have been reported to suppress the expression of colon tumors in rats. In this study, we investigated the effect of consumption egg yolk proteins on cell proliferation in a rat model of azoxymethane (AOM)-induced colon cancer. We hypothesize, based on the literature of egg yolk protein actions, that they protect against colon tumor development. Therefore, male F344 rats were fed a purified AIN-93G diet containing either 20% casein (control) or 20% egg yolk proteins for 5 weeks. After 1 week on the experimental diet, the rats were administered weekly subcutaneous injections of saline or AOM for 2 weeks to induce aberrant crypt foci. Rats were administered an intraperitoneal injection of 5-bromo-2'-deoxyuridine 1 hour before being euthanized for examination of DNA synthesis in the colonic mucosa. The contents of the cecum were analyzed for the presence of short-chain fatty acids (SCFAs). In the AOM-injected rats, the yolk protein diet suppressed aberrant crypt foci formation and reduced the proliferative 5-bromo-2'-deoxyuridine-labeling index in the proximal colon when compared with the control diet. A significant increase in cecal SCFAs was observed in the rats that were fed egg yolk proteins. These results indicate that dietary egg yolk proteins have a preventive effect on AOM-induced large bowel carcinogenesis in rats; it exerts this effect by altering cell proliferation through SCFA production. This study suggests that the consumption of egg yolk proteins might be protective against colon carcinogenesis. PMID:19185779

  15. Reduction of DMH-induced colon tumors in rats fed psyllium husk or cellulose.

    PubMed

    Roberts-Andersen, J; Mehta, T; Wilson, R B

    1987-01-01

    The effect of feeding psyllium husk, a water-soluble fiber, and cellulose, a water-insoluble fiber, against chemically induced colon cancer was investigated in rats. Adult male rats were fed semipurified diets containing 20% fat, no fiber, or 10% psyllium husk or cellulose for 22 weeks. Tumors were induced in one-half of the rats fed each diet by the gastric intubation of 1,2-dimethylhydrazine (DMH) during Weeks 3-11. In terms of the number of animals with tumors in each group, psyllium strongly reduced the tumorigenicity of DMH and cellulose moderately reduced tumorigenicity, whereas the two fibers did not differ significantly from each other with respect to tumorigenicity. Psyllium-fed rats had the highest fecal aerobic counts, lowest beta-glucuronidase, and highest 7-alpha-dehydroxylase activities. The psyllium diet also resulted in increased fecal output and percent moisture. Rats fed cellulose tended to have greater fecal bulk and lower beta-glucuronidase activity compared with rats fed no fiber and lower 7-alpha-dehydroxylase activity compared with rats fed psyllium husk. PMID:2819829

  16. Contribution of peripheral opioid receptors to the trimebutine-induced contractions of the proximal colon in anesthetized rats.

    PubMed

    Nagasaki, M; Yamada, K; Ikezawa, K; Tamaki, H

    1989-02-01

    In this study we investigated the involvement of opioid receptors in the contractile response to trimebutine using with the proximal colon of anesthetized rats. Trimebutine (3 mg/kg i.v.) enhanced spontaneous contractions of the proximal colon in anesthetized rats. The contractile response was partially inhibited by intravenous administration of an opioid antagonist, naloxone at 1 approximately 30 micrograms/kg, but was hardly depressed by intracisternal administration of naloxone (30 micrograms/kg). Morphine (30 micrograms/kg i.v.) evoked colonic contractions which were abolished by intravenous naloxone (30 micrograms/kg). These results suggest that the colonic contractions evoked by trimebutine in anesthetized rats are, in part, mediated by peripheral opioid receptors. PMID:2560095

  17. Effect of resistant starch on genotoxin-induced apoptosis, colonic epithelium, and lumenal contents in rats.

    PubMed

    Le Leu, Richard K; Brown, Ian L; Hu, Ying; Young, Graeme P

    2003-08-01

    The effect of different doses of a type-2 resistant starch (RS) in the form of high amylose cornstarch (HAS) on the intralumenal environment and the acute-apoptotic response to a genotoxic carcinogen (AARGC) in the colon was assessed to determine if changes in lumenal conditions were associated with an enhanced apoptotic response to DNA damage. The control diet was a modified form of the AIN-76 diet containing fully digestible starch but no dietary fibre. HAS was added to the control diet at the expense of digestible starch to give 10% HAS, 20% HAS and 30% HAS. Rats were fed the different experimental diets for a period of 4 weeks, after which a single injection of azoxymethane was given to induce DNA damage in the colonic epithelium; 6 h later AARGC was measured. Other measures included fecal and cecal short chain fatty acids (SCFA) and pH, and cell proliferation in the colonic epithelium. In HAS-supplemented rats, fermentation events were significantly increased in both cecum and feces. There was a progressive decrease in pH in both the cecum and feces as the amount of HAS in the diet increased. SCFA concentrations, including butyrate, were significantly elevated by HAS with higher levels being observed in the cecum than in the feces. There was a significant increase in colonic AARGC with HAS doses of 20 and 30% (P < 0.01) but not with 10% HAS. Cell proliferation was not affected by any dose of HAS. Correlations with AARGC, independent of dietary group, were seen for fecal SCFAs and pH, suggesting that fermentation events, might explain the effect of RS on AARGC. Altering amounts of dietary RS changes fermentative activity in the colon. Increased RS is associated with enhanced AARGC. Changes in amount of fermentable substrate are capable of changing the biological response to DNA damage. PMID:12807738

  18. Neurotensin Changes Propulsive Activity into a Segmental Motor Pattern in the Rat Colon

    PubMed Central

    Li, Hongfei; Chen, Ji-Hong; Yang, Zixian; Huang, Min; Yu, Yuanjie; Tan, Shiyun; Luo, Hesheng; Huizinga, Jan D

    2016-01-01

    Background/Aims Neurotensin is a gut-brain peptide with both inhibitory and excitatory actions on the colonic musculature; our objective was to understand the implications of this for motor patterns occurring in the intact colon of the rat. Methods The effects of neurotensin with concentrations ranging from 0.1–100 nM were studied in the intact rat colon in vitro, by investigating spatio-temporal maps created from video recordings of colonic motility before and after neurotensin. Results Low concentration of neurotensin (0.1–1 nM) inhibited propagating long distance contractions and rhythmic propagating motor complexes; in its place a slow propagating rhythmic segmental motor pattern developed. The neurotensin receptor 1 antagonist SR-48692 prevented the development of the segmental motor pattern. Higher concentrations of neurotensin (10 nM and 100 nM) were capable of restoring long distance contraction activity and inhibiting the segmental activity. The slow propagating segmental contraction showed a rhythmic contraction—relaxation cycle at the slow wave frequency originating from the interstitial cells of Cajal associated with the myenteric plexus pacemaker. High concentrations given without prior additions of low concentrations did not evoke the segmental motor pattern. These actions occurred when neurotensin was given in the bath solution or intraluminally. The segmental motor pattern evoked by neurotensin was inhibited by the neural conduction blocker lidocaine. Conclusions Neurotensin (0.1–1 nM) inhibits the dominant propulsive motor patterns of the colon and a distinct motor pattern of rhythmic slow propagating segmental contractions develops. This motor pattern has the hallmarks of haustral boundary contractions. PMID:26882114

  19. 17β-Oestradiol acutely regulates Cl− secretion in rat distal colonic epithelium

    PubMed Central

    Condliffe, Steven B; Doolan, Christina M; Harvey, Brian J

    2001-01-01

    In this study we used the short circuit current (ISC) technique to measure the non-genomic effects of the female sex steroid 17β-oestradiol (E2) on electrogenic transepithelial ion transport in rat distal colonic epithelium. Basal ISC was largely composed of a transepithelial Cl− secretory component with minimal electrogenic Na+ movement. E2 (1-100 nm) caused a significant decrease in basal ISC after 15 min. In addition, pre-treating colonic epithelial tissues with E2 (0.1-100 nm) for 10 min significantly reduced forskolin (20 μm)-induced Cl− secretion. E2 also down-regulated Cl− secretion which was pre-stimulated by forskolin. Cl− secretory responses to the Ca2+-dependent secretagogue carbachol (10 μm) were also significantly reduced in the presence of E2 (10- 100 nm). However, E2 had no effect on amiloride-sensitive Na+ absorption. The rapid anti-secretory effect of E2 was abolished in the presence of the intracellular Ca2+ chelator BAPTA (50 μm) or the protein kinase C (PKC) inhibitor chelerythrine chloride (1 μm). However, in the presence of the nuclear oestrogen receptor antagonist tamoxifen (10 μm), E2 still produced an inhibition of Cl− secretion. Testosterone, progesterone and 17α-oestradiol had no significant effect on colonic Cl− secretion. Also, E2 (100 nm) did not alter Cl− secretion in colonic epithelia isolated from male rats. We conclude that E2 inhibits colonic Cl− secretion via a non-genomic pathway that involves intracellular Ca2+ and PKC. It is possible that this gender-specific mechanism contributes to the salt and water retention associated with high E2 states. PMID:11136857

  20. 17beta-oestradiol acutely regulates Cl- secretion in rat distal colonic epithelium.

    PubMed

    Condliffe, S B; Doolan, C M; Harvey, B J

    2001-01-01

    In this study we used the short circuit current (ISC) technique to measure the non-genomic effects of the female sex steroid 17beta-oestradiol (E2) on electrogenic transepithelial ion transport in rat distal colonic epithelium. Basal ISC was largely composed of a transepithelial Cl- secretory component with minimal electrogenic Na+ movement. E2 (1-100 nM) caused a significant decrease in basal ISC after 15 min. In addition, pre-treating colonic epithelial tissues with E2 (0.1-100 nM) for 10 min significantly reduced forskolin (20 microM)-induced Cl- secretion. E2 also down-regulated Cl- secretion which was pre-stimulated by forskolin. Cl- secretory responses to the Ca2+-dependent secretagogue carbachol (10 microM) were also significantly reduced in the presence of E2 (10- 100 nM). However, E2 had no effect on amiloride-sensitive Na+ absorption. The rapid anti-secretory effect of E2 was abolished in the presence of the intracellular Ca2+ chelator BAPTA (50 microM) or the protein kinase C (PKC) inhibitor chelerythrine chloride (1 microM). However, in the presence of the nuclear oestrogen receptor antagonist tamoxifen (10 microM), E2 still produced an inhibition of Cl- secretion. Testosterone, progesterone and 17alpha-oestradiol had no significant effect on colonic Cl- secretion. Also, E2 (100 nM) did not alter Cl- secretion in colonic epithelia isolated from male rats. We conclude that E2 inhibits colonic Cl- secretion via a non-genomic pathway that involves intracellular Ca2+ and PKC. It is possible that this gender-specific mechanism contributes to the salt and water retention associated with high E2 states. PMID:11136857

  1. Characterization of apical potassium channels induced in rat distal colon during potassium adaptation.

    PubMed Central

    Butterfield, I; Warhurst, G; Jones, M N; Sandle, G I

    1997-01-01

    1. Chronic dietary K+ loading stimulates an active K+ secretory process in rat distal colon, which involves an increase in the macroscopic apical K+ conductance of surface epithelial cells. In the present study, the abundance and characteristics of K+ channels constituting this enhanced apical K+ conductance were evaluated using patch clamp recording techniques. 2. In isolated non-polarized surface cells, K+ channels were seen in 9 of 90 (10%) cell-attached patches in cells from control animals, and in 247 of 437 (57%) cell-attached patches in cells from K(+)-loaded animals, with a significant (P < 0.001) shift in distribution density. Similarly, recordings from cell-attached patches of the apical membrane of surface cells surrounding the openings of distal colonic crypts revealed identical K+ channels in 1 of 11 (9%) patches in control animals, and in 9 of 13 (69%) patches in K(+)-loaded animals. 3. In isolated surface cells and surface cells in situ, K+ channels had mean slope conductances of 209 +/- 6 and 233 +/- 14 pS, respectively, when inside-out patches were bathed symmetrically in K2SO4 solution. The channels were sensitive to 'cytosolic' Ca2+ concentration, were voltage sensitive at 'cytosolic' Ca2+ concentrations encountered in colonic epithelial cells, and were inhibited by 1 mM quinidine, 20 mM TEA or 5 mM Ba2+ ions. 4. The data show that dietary K+ loading increases the abundance of Ca(2+)- and voltage-sensitive large-conductance K+ channels in the apical membrane of surface cells in rat distal colon. These channels constitute the enhanced macroscopic apical K+ conductance previously identified in these cells, and are likely to play a critical role in the active K+ secretory process that typifies this model of colonic K+ adaptation. PMID:9218214

  2. In Vivo Evaluation of 5-ASA Colon-Specific Tablets Using Experimental-Induced Colitis Rat Animal Model.

    PubMed

    Sawarkar, Sujata P; Deshpande, S G; Bajaj, A N; Nikam, V S

    2015-12-01

    Colonic drug delivery is intended not only for local treatment in inflammatory bowel disease (IBD) but also for systemic delivery of therapeutics. Intestinal myeloperoxidase (MPO) determination could be used to estimate the average level of inflammation in colon as well as to determine the efficacy of drugs to be used in the treatment of inflammatory bowel diseases or study the specificity of dosage forms to be used for colonic targeting of anti-inflammatory drugs. Colonic prodrug sulfasalazine (SASP) gets metabolized to give 5-aminosalicylic acid (5-ASA), which is the active portion of SASP. However, when given orally, 5-ASA is absorbed in upper part of gastrointestinal tract (GIT) and not made available in colon. In the present study, colon-targeted delivery of 5-ASA was achieved by formulating tablets with two natural polymers namely guar gum and pectin using compression coating method. Colonic specificity of 5-ASA tablets (prepared using guar gum and pectin as polymers) was evaluated in vitro using simulated fluids mimicking in vivo environment as well as in vivo method using chemically (2,4,6-trinitrobenzenesulfonic acid and acetic acid)-induced colitis rat model. Both colon-specific formulations of 5-ASA (guar gum and pectin) were observed to be more effective in reducing inflammation in chemically induced colitis rat models when compared to colon-specific prodrug sulfasalazine as well as conventional 5-ASA administered orally. PMID:26017284

  3. Lack of efficacy of blueberry in nutritional prevention of azoxymethane-initiated cancers of rat small intenstions and colon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the efficacy of freeze-dried blueberry (BB) in inhibition of formation of azoxymethane (AOM)-induced colon aberrant crypt foci (ACF) and intestine tumors in male and female Sprague-Dawley rats. Pregnant rats were fed a control diet with or without 10% BB; progeny were weaned to the same...

  4. Consistent and fast inhibition of colon carcinogenesis by polyethylene glycol in mice and rats given various carcinogens.

    PubMed

    Corpet, D E; Parnaud, G; Delverdier, M; Peiffer, G; Taché, S

    2000-06-15

    We have previously shown that dietary polyethylene-glycol (PEG) suppresses the occurrence of azoxymethane-induced cancers in an accelerated rat model of colon carcinogenesis. To determine the consistency of this preventive effect, we carried out a long-term study in rats fed the standard American Institute of Nutrition 1976 diet, and 7 short-term prevention studies in rodents. A total of 337 F344 rats, 20 Sprague Dawley rats, and 40 OF1 mice were all given initiating dose(s) of colon carcinogen, and were randomly allocated to experimental groups 7 d later. Treated groups received drinking water containing 5% PEG. After 30 or 162 d, the animals were examined for aberrant crypt foci or tumors in the colon. After two 20 mg/kg azoxymethane injections, the number of F344 rats with colon tumor was lower in rats receiving PEG for 162 d than in carcinogen-injected controls, 5/21 versus 25/27 (P < 0.0001). PEG-fed rats had no invasive cancer, and 10 times fewer colon tumors than controls (0.3+/-0.1 and 3.1+/-0.5 respectively, P < 0.0001). A three-day PEG treatment was sufficient to halve the number of azoxymethane-induced aberrant crypt foci in F344 rats (P = 0.0006). After 16 d of treatment, PEG-fed rats had five times fewer foci than controls (21+/-14 and 100+/-23 respectively, P < 0.0001), but the inhibition was reversible in part when treatment was discontinued. Aberrant crypt foci initiated by N-methyl-N-nitrosourea intra-rectally (40 mg/kg) or by 2-amino-3,4-dimethylimidazo(4,5-f)quinoline p.o. (2 x 200 mg/kg) were suppressed by PEG (P < 0.0001 and P = 0.003 respectively). PEG was active in F344 rats, in Sprague Dawley rats (P = 0.0005), and in OF1 mice (P = 0.001). PEGs with MW between 3350 and 12000 (but not PEG 400), and PEG 8000 from five suppliers, markedly inhibited azoxymethane-induced aberrant crypt foci (all P < 0.01). The prevention was stronger in rats fed a high-fat diet (P < 0.0001) than in rats fed a rodent chow (P = 0.02). PEG was thus a fast

  5. Colonic Hypersensitivity and Sensitization of Voltage-gated Sodium Channels in Primary Sensory Neurons in Rats with Diabetes

    PubMed Central

    Hu, Ji; Song, Zhen-Yuan; Zhang, Hong-Hong; Qin, Xin; Hu, Shufen; Jiang, Xinghong; Xu, Guang-Yin

    2016-01-01

    Background/Aims Patients with long-standing diabetes often demonstrate intestinal dysfunction and abdominal pain. However, the pathophysiology of abdominal pain in diabetic patients remains elusive. The purpose of study was to determine roles of voltage-gated sodium channels in dorsal root ganglion (DRG) in colonic hypersensitivity of rats with diabetes. Methods Diabetic models were induced by a single intraperitoneal injection of streptozotocin (STZ; 65 mg/kg) in adult female rats, while the control rats received citrate buffer only. Behavioral responses to colorectal distention were used to determine colonic sensitivity in rats. Colon projection DRG neurons labeled with DiI were acutely dissociated for measuring excitability and sodium channel currents by whole-cell patch clamp recordings. Western blot analysis was employed to measure the expression of NaV1.7 and NaV1.8 of colon DRGs. Results STZ injection produced a significantly lower distention threshold than control rats in responding to colorectal distention. STZ injection also depolarized the resting membrane potentials, hyperpolarized action potential threshold, decreased rheobase and increased frequency of action potentials evoked by 2 and 3 times rheobase and ramp current stimulation. Furthermore, STZ injection enhanced neuronal sodium current densities of DRG neurons innervating the colon. STZ injection also led to a significant upregulation of NaV1.7 and NaV1.8 expression in colon DRGs compared with age and sex-matched control rats. Conclusions Our results suggest that enhanced neuronal excitability following STZ injection, which may be mediated by upregulation of NaV1.7 and NaV1.8 expression in DRGs, may play an important role in colonic hypersensitivity in rats with diabetes. PMID:26459453

  6. Cyclic AMP-induced K+ secretion occurs independently of Cl- secretion in rat distal colon.

    PubMed

    Sandle, Geoffrey I; Rajendran, Vazhaikkurichi M

    2012-08-01

    cAMP induces both active Cl(-) and active K(+) secretion in mammalian colon. It is generally assumed that a mechanism for K(+) exit is essential to maintain cells in the hyperpolarized state, thus favoring a sustained Cl(-) secretion. Both Kcnn4c and Kcnma1 channels are located in colon, and this study addressed the questions of whether Kcnn4c and/or Kcnma1 channels mediate cAMP-induced K(+) secretion and whether cAMP-induced K(+) secretion provides the driving force for Cl(-) secretion. Forskolin (FSK)-enhanced short-circuit current (indicator of net electrogenic ion transport) and K(+) fluxes were measured simultaneously in colonic mucosa under voltage-clamp conditions. Mucosal Na(+) orthovanadate (P-type ATPase inhibitor) inhibited active K(+) absorption normally present in rat distal colon. In the presence of mucosal Na(+) orthovanadate, serosal FSK induced both K(+) and Cl(-) secretion. FSK-induced K(+) secretion was 1) not inhibited by either mucosal or serosal 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34; a Kcnn4 channel blocker), 2) inhibited (92%) by mucosal iberiotoxin (Kcnma1 channel blocker), and 3) not affected by mucosal cystic fibrosis transmembrane conductance regulator inhibitor (CFTR(inh)-172). By contrast, FSK-induced Cl(-) secretion was 1) completely inhibited by serosal TRAM-34, 2) not inhibited by either mucosal or serosal iberiotoxin, and 3) completely inhibited by mucosal CFTR(inh)-172. These results indicate that cAMP-induced colonic K(+) secretion is mediated via Kcnma1 channels located in the apical membrane and most likely contributes to stool K(+) losses in secretory diarrhea. On the other hand, cAMP-induced colonic Cl(-) secretion requires the activity of Kcnn4b channels located in the basolateral membrane and is not dependent on the concurrent activation of apical Kcnma1 channels. PMID:22648950

  7. Differential distribution of protein kinases along the crypt-to-lumen regions of rat colonic epithelium.

    PubMed Central

    Schwartz, B; Fraser, G M; Levy, J; Sharoni, Y; Guberman, R; Krawiec, J; Lamprecht, S A

    1988-01-01

    The activity of cAMP-dependent and cAMP-independent protein kinases, a class of enzymes involved in the regulation of cell proliferation was measured in rat colonic epithelium. Sequential cell populations harvested by a stepwise scraping technique from colonic crypt regions were identified by histology and incorporation of [3H]-thymidine into DNA. cAMP-independent phosphorylation of casein, in the presence of [gamma-32P]ATP, was markedly suppressed by quercetin, a bioflavonoid known to inhibit G-type casein kinase, protein kinase-C and tyrosine protein kinase. Conversely, the cyclic nucleotide regulatable form requiring histone as substrate was responsive to the action of the heat stable protein kinase inhibitor. The protein kinase species were characterised and partially purified by DEAE-cellulose chromatography. The activity of cAMP-dependent protein kinase in colonic cytosols (pmol 32P/min/mg protein, means (SE)) increased from 129.4 (15.9) in superficial cell populations to 238.5 (31.4) in lower crypt cell fractions (p less than 0.01). Colonic cAMP-independent protein kinase activity increased from 87.3 (15.6) in surface cell preparations to 178.1 (30.0) in lower crypt cell populations (p less than 0.02). A comparable activity gradient was observed in membrane fractions. The activity gradient persisted when the results were expressed as a function of cellular DNA. These findings indicate that protein kinases display a defined topological segregation along the colonic crypt regions and that during migration to the lumen colonic cells attenuate enzyme signals supposedly related to tissue growth. PMID:2848753

  8. Butyrate delivered by butyrylated starch increases distal colonic epithelial apoptosis in carcinogen-treated rats.

    PubMed

    Clarke, Julie M; Young, Graeme P; Topping, David L; Bird, Anthony R; Cobiac, Lynne; Scherer, Benjamin L; Winkler, Jessica G; Lockett, Trevor J

    2012-01-01

    Animal studies show that increasing large bowel butyrate concentration through ingestion of butyrylated or resistant starches opposes carcinogen-induced tumorigenesis, which is consistent with population data linking greater fiber consumption with lowered colorectal cancer (CRC) risk. Butyrate has been shown to regulate the apoptotic response to DNA damage. This study examined the impact of increasing large bowel butyrate concentration by dietary butyrylated starch on the colonic epithelium of rats treated with the genotoxic carcinogen azoxymethane (AOM). Four groups of 10 male rats were fed AIN-93G based-diets containing either low amylose maize starch (LAMS), LAMS with 3% tributyrin, 10% high amylose maize starch (HAMS) or 10% butyrylated HAMS (HAMSB). HAMS and HAMSB starches were cooked by heating in water. After 4 weeks, rats were injected once with AOM and killed 6 h later. Rates of apoptosis and proliferation were measured in colonic epithelium. Short-chain fatty acid concentrations in large bowel digesta and hepatic portal venous plasma were higher in HAMSB than all other groups. Apoptotic rates in the distal colon were increased by HAMSB and correlated with luminal butyrate concentrations but cellular proliferation rates were unaffected by diet. The increase in apoptosis was most marked in the base and proliferative zone of the crypt. Regulation of luminal butyrate using HAMSB increases the rates of apoptotic deletion of DNA-damaged colonocytes. We propose this pro-apoptotic function of butyrate plays a major role reducing tumour formation in the AOM-treated rat and that these data support a potential protective role of butyrate in CRC. PMID:22080572

  9. Bioavailability of lemon verbena (Aloysia triphylla) polyphenols in rats: impact of colonic inflammation.

    PubMed

    Felgines, Catherine; Fraisse, Didier; Besson, Catherine; Vasson, Marie-Paule; Texier, Odile

    2014-05-28

    Lemon verbena (Aloysia triphylla) infusion, a widely consumed herbal tea, contains significant amounts of polyphenols such as flavone diglucuronides and phenylpropanoid glycosides (mainly verbascoside). We have recently shown that lemon verbena infusion offers beneficial effects against dextran sodium sulphate (DSS)-induced colonic inflammation in rats. The present study aimed to evaluate the bioavailability and intestinal absorption of polyphenols derived from lemon verbena infusion in both healthy and colitic rats. For this purpose, lemon verbena infusion was given to rats ad libitum for 14 d, and then 4 % DSS was added to the infusion for 7 d. Before and after DSS administration, 24 h urinary excretion of polyphenols was determined. Flavones were excreted in the urine as conjugated aglycones, and their excretion was not significantly altered by colonic inflammation. Only trace amounts of verbascoside were excreted in the urine, but various metabolites (hydroxycinnamic acids) were detected. The urinary excretion of hydroxycinnamic acids, particularly that of caffeic acid, increased after DSS administration (P< 0·05). Only flavone aglycones (luteolin and diosmetin) were excreted in the faeces in small proportions (3·2 % of ingested flavones). Intestinal absorption of lemon verbena polyphenols was examined using an in situ intestinal perfusion model. Intestinal absorption of verbascoside and flavone diglucuronides did not significantly differ between the healthy and colitic rats. Collectively, these results show that intestinal absorption and urinary excretion of lemon verbena flavone diglucuronides were not altered by colonic inflammation, but that urinary excretion of hydroxycinnamic acids derived from verbascoside was affected in a colitic situation. PMID:24513110

  10. Effect of pinaverium bromide on stress-induced colonic smooth muscle contractility disorder in rats

    PubMed Central

    Dai, Yun; Liu, Jian-Xiang; Li, Jun-Xia; Xu, Yun-Feng

    2003-01-01

    AIM: To investigate the effect of pinaverium bromide, a L-type calcium channel blocker with selectivity for the gastrointestinal tract on contractile activity of colonic circular smooth muscle in normal or cold-restraint stressed rats and its possible mechanism. METHODS: Cold-restraint stress was conducted on rats to increase fecal pellets output. Each isolated colonic circular muscle strip was suspended in a tissue chamber containing warm oxygenated Tyrode-Ringer solution. The contractile response to ACh or KCl was measured isometrically on ink-writing recorder. Incubated muscle in different concentrations of pinaverium and the effects of pinaverium were investigated on ACh or KCl-induced contraction. Colon smooth muscle cells were cultured from rats and [Ca2+]i was measured in cell suspension using the Ca2+ fluorescent dye fura-2/AM. RESULTS: During stress, rats fecal pellet output increased 61% (P < 0.01). Stimulated with ACh or KCl, the muscle contractility was higher in stress than that in control. Pinaverium inhibited the increment of [Ca2+]i and the muscle contraction in response to ACh or KCl in a dose dependent manner. A significant inhibition of pinaverium to ACh or KCl induced [Ca2+]i increment was observed at 10-6 mol/L. The IC50 values for inhibition of ACh induced contraction for the stress and control group were 1.66 × 10-6 mol/L and 0.91 × 10-6 mol/L, respectively. The IC50 values for inhibition of KCl induced contraction for the stress and control group were 8.13 × 10-7 mol/L and 3.80 × 10-7 mol/L, respectively. CONCLUSION: Increase in [Ca2+]i of smooth muscle cells is directly related to the generation of contraction force in colon. L-type Ca2+ channels represent the main route of Ca2+ entry. Pinaverium inhibits the calcium influx through L-type channels; decreases the contractile response to many kinds of agonists and regulates the stress-induced colon hypermotility. PMID:12632518

  11. Açai (Euterpe oleracea Mart.) feeding attenuates dimethylhydrazine-induced rat colon carcinogenesis.

    PubMed

    Fragoso, Mariana F; Romualdo, Guilherme R; Ribeiro, Daniel A; Barbisan, Luis F

    2013-08-01

    This study investigated the protective effect of spray-dried açaí powder (AP) intake on colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats. After 4 weeks of DMH administrations, the groups were fed with standard diet, a diet containing 2.5% or 5.0% AP or a diet containing 0.2% N-acetylcysteine (NAC) for 10 weeks, using aberrant crypt foci (ACF) as the endpoint. Additionally, two groups were fed with standard diet or a diet containing 5.0% AP for 20 weeks, using colon tumors as the endpoint. In ACF assay, a reduction in the number of aberrant crypts (ACs) and ACF (1-3 AC) were observed in the groups fed with 5.0% AP (37% AC and 47% ACF inhibition, p=0.036) and 0.2% NAC (39% AC and 41% ACF inhibition, p=0.042). In tumor assay, a reduction in the number of invasive tumors (p<0.005) and tumor multiplicity (p=0.001) was observed in the group fed with 5.0% AP. Also, a reduction in tumor Ki-67 cell proliferation (p=0.003) and net growth index (p=0.001) was observed in the group fed with 5.0% AP. Therefore the findings of this study indicate that AP feeding may reduce the development of chemically-induced rat colon carcinogenesis. PMID:23597449

  12. Azithromycin and erythromycin ameliorate the extent of colonic damage induced by acetic acid in rats

    SciTech Connect

    Mahgoub, Afaf . E-mail: afaf_mahgoub@yahoo.com; El-Medany, Azza; Mustafa, Ali; Arafah, Maha; Moursi, Mahmoud

    2005-05-15

    Ulcerative colitis is a common inflammatory bowel disease (IBD) of unknown etiology. Recent studies have revealed the role of some microorganisms in the initiation and perpetuation of IBD. The role of antibiotics in the possible modulation of colon inflammation is still uncertain. In this study, we evaluated the effects of two macrolides, namely azithromycin and erythromycin, at different doses on the extent and severity of ulcerative colitis caused by intracolonic administration of 3% acetic acid in rats. The lesions and the inflammatory response were assessed by histology and measurement of myeloperoxidase (MPO) activity, nitric oxide synthetase (NOS) and tumor necrosis factor alpha (TNF{alpha}) in colonic tissues. Inflammation following acetic acid instillation was characterized by oedema, diffuse inflammatory cell infiltration and necrosis. Increase in MPO, NOS and TNF{alpha} was detected in the colonic tissues. Administration of either azithromycin or erythromycin at different dosage (10, 20 and 40 mg/kg orally, daily for 5 consecutive days) significantly (P < 0.05) reduced the colonic damage, MPO and NOS activities as well as TNF{alpha} level. This reduction was highly significant with azithromycin when given at a dose of 40 mg/kg. It is concluded that azithromycin and erythromycin may have a beneficial therapeutic role in ulcerative colitis.

  13. The probiotic Escherichia coli Nissle 1917 inhibits propagating colonic contractions in the rat isolated large intestine.

    PubMed

    Dalziel, J E; Mohan, V; Peters, J; Anderson, R C; Gopal, P K; Roy, N C

    2015-01-01

    The objective of this research was to test an in vitro motility model by investigating whether a probiotic that reduces diarrhea in humans would reduce motility in the rat colon in vitro. The probiotic Escherichia coli Nissle 1917 (EcN) the active ingredient in Mutaflor® was used as an example probiotic because it is effective for treating infectious diarrheal diseases. The effect of EcN on motility was compared in two colonic preparations. In distal colon segments EcN extract decreased the tension of spontaneous contractions by 74% and frequency by 46% compared with pre-treatment controls. In the whole large intestine the number of synchronized spontaneous propagating contractions decreased by 86% when EcN extract was applied externally and 69% when applied via the lumen compared with pre-treatment. From the inhibition produced by EcN extract in the distal colon segment a myogenic action was inferred and in the whole large intestine neural involvement was implicated. Both are consistent with its anti-diarrheal effect in humans. PMID:25415771

  14. Determination of short-circuit current in the in vivo perfused rat colon.

    PubMed

    Knauf, H; Haag, K; Lübcke, R; Berger, E; Gerok, W

    1984-02-01

    Current pulses (I) were injected into the lumen of proximal colonic segments in vivo, and the corresponding voltage deflections (delta PD) superimposed on the transcolonic PD were recorded. From the exponential decay of delta PD along the colon axis, the electrical length constant (lambda) was determined. Based on cable analysis the input resistance (= delta PD x = 0/I) and lambda made it possible to calculate the specific resistance (Rm) of the colonic epithelium as 128 +/- 16 omega X cm2. As Rm proved to be an ohmic resistor, the extrapolation from open-circuit PD (8-12 mV, lumen negative) to zero PD was feasible and made the calculation of short-circuit current (= PD/Rm) equal to 70 +/- 16 microA/cm2. In the presence of amiloride short-circuit current decreased to about 50%, whereas with theophylline it increased by about 30%. Substitution of luminal Na+ with choline or Cl- with cyclamate was associated with a marked increase of Rm. The rheogenic component of net Na+ transport was estimated to be only 8%. Electroneutral Na+ absorption functionally coupled with Cl- absorption displayed the characteristic feature of ion transport in the rat proximal colon. PMID:6320673

  15. Adenosine A1 receptors mediate the intracisternal injection of orexin-induced antinociceptive action against colonic distension in conscious rats.

    PubMed

    Okumura, Toshikatsu; Nozu, Tsukasa; Kumei, Shima; Takakusaki, Kaoru; Miyagishi, Saori; Ohhira, Masumi

    2016-03-15

    We have recently demonstrated that orexin acts centrally through the brain orexin 1 receptors to induce an antinociceptive action against colonic distension in conscious rats. Adenosine signaling is capable of inducing an antinociceptive action against somatic pain; however, the association between changes in the adenosinergic system and visceral pain perception has not been investigated. In the present study, we hypothesized that the adenosinergic system may be involved in visceral nociception, and thus, adenosine signaling may mediate orexin-induced visceral antinociception. Visceral sensation was evaluated based on the colonic distension-induced abdominal withdrawal reflex (AWR) in conscious rats. Subcutaneous (0.04-0.2mg/rat) or intracisternal (0.8-4μg/rat) injection of N(6)-cyclopentyladenosine (CPA), an adenosine A1 receptor (A1R) agonist, increased the threshold volume of colonic distension-induced AWR in a dose-dependent manner, thereby suggesting that CPA acts centrally in the brain to induce an antinociceptive action against colonic distension. Pretreatment with theophylline, an adenosine antagonist, or 1,3-dipropyl-8-cyclopentylxanthine, an A1R antagonist, subcutaneously injected potently blocked the centrally injected CPA- or orexin-A-induced antinociceptive action against colonic distension. These results suggest that adenosinergic signaling via A1Rs in the brain induces visceral antinociception and that adenosinergic signaling is involved in the central orexin-induced antinociceptive action against colonic distension. PMID:26944127

  16. Influence of prenatal corticosteroids on bacterial colonization in the newborn rat.

    PubMed

    Schiffrin, E J; Carter, E A; Walker, W A; Frieberg, E; Benjamin, J; Israel, E J

    1993-10-01

    The interactions between bacteria and the host's intestinal barrier appear to be important regulators of bacterial colonization. In this study we investigated the effect of prenatal corticosteroids, known to accelerate the intestinal maturation of newborn rats, on bacterial colonization in the rat pup. Pregnant rats were treated with either cortisone acetate or normal saline on days 18-21 of gestation and were allowed to deliver spontaneously. The pups, after normal delivery, were sacrificed at different times during the first 10 days of life. The entire small intestine was removed, and each lumen was flushed to exclude nonadherent, transient organisms and homogenized. Tenfold dilutions were plated on horse-blood agar (total bacteria) and MacConkey's medium (gram-negatives). Quantitation and bacterial typification was determined after 24 h of incubation at 37 degrees C. Total bacteria and gram-negatives found in association with the mucosa were significantly lower in pups prenatally treated with steroids. These changes were not related to any changes in motility or intraluminal digestion. This suggests that the developmental condition of the host's intestinal barrier may be an important regulator of the bacterial microenvironment of the newborn small intestinal mucosa. PMID:8271126

  17. Stereotaxic delivery of corticosterone to the amygdala modulates colonic sensitivity in rats.

    PubMed

    Greenwood-Van Meerveld, B; Gibson, M; Gunter, W; Shepard, J; Foreman, R; Myers, D

    2001-03-01

    Episodes of anxiety are often associated with the onset or exacerbation of visceral pain in patients with irritable bowel syndrome (IBS). The central amygdaloid nucleus (CeA) is a key limbic structure involved in the expression of anxiety as well as a major site for regulating autonomic and visceral responses to stress. Previous experiments have shown that glucocorticoids can act directly at the CeA to increase the level of anxiety in rats. Therefore, the goal of this study was to examine the effect of stereotaxic delivery of corticosterone into the CeA on the development of visceral hypersensitivity by measuring visceromotor response to colorectal distention in rats. Stereotaxic delivery of corticosterone to the CeA increases indices of anxiety and produces a hypersensitive colon as demonstrated by an exaggerated visceromotor response to colorectal distention in the F344 rat strain. Our findings suggest that modulation of anxiety by manipulating amygdala function with corticosterone induced colonic hypersensitivity via descending neuronal pathways from the CeA. PMID:11223001

  18. Successful radioimmunotherapy of established syngeneic rat colon carcinoma with 211At-mAb

    PubMed Central

    2013-01-01

    Background Most carcinomas are prone to metastasize despite successful treatment of the primary tumor. One way to address this clinical challenge may be targeted therapy with α-emitting radionuclides such as astatine-211 (211At). Radioimmunotherapy utilizing α-particle emitting radionuclides is considered especially suitable for the treatment of small cell clusters and single cells, although lesions of different sizes may also be present in the patient. The aim of this study was primarily to evaluate the toxicity and secondarily in vivo efficacy of a 211At-labeled monoclonal antibody (mAb) directed against colon carcinoma with tumor diameters of approximately 10 mm. Methods Eighteen rats with subperitoneal syngeneic colon carcinoma were allocated to three groups of six animals together with three healthy rats in each group. The groups were injected intravenously with either 150 μg of unlabeled mAbs (controls) or 2.5 or 5 MBq 211At-mAbs directed towards the Lewis Y antigen expressed on the cell membrane of several carcinomas. Tumor volume, body weight, and blood cell counts were monitored for 100 days after treatment. Results Local tumors were non-palpable in five out of six rats after treatment with both activities of 211At-mAbs, compared to one out of six in the control group. At the study end, half of the animals in each group given 211At-BR96 and one animal in the control group were free from disease. Radioimmunotherapy resulted in dose-dependent, transient weight loss and myelotoxicity. Survival was significantly better in the groups receiving targeted alpha therapy than in those receiving unlabeled mAbs. Conclusions This study demonstrates the possibility of treating small, solid colon carcinoma tumors with α-emitting radionuclides such as 211At bound to mAbs, with tolerable toxicity. PMID:23557183

  19. The effects of Pycnogenol(®) on colon anastomotic healing in rats given preoperative irradiation.

    PubMed

    Değer, K Cumhur; Şeker, Ahmet; Özer, Ilter; Bostancı, E Birol; Dalgıç, Tahsin; Akmansu, Müge; Ekinci, Özgür; Erçin, Uğur; Bilgihan, Ayşe; Akoğlu, Musa

    2013-01-01

    Pycnogenol(®) has excellent radical scavenging properties and enhances the production of antioxidative enzymes which contributes to the anti-inflammatory effect of the extract. Irradiation delivered to the abdominal region, typically results in severe damage to the intestinal mucosa. The effects of ionizing radiation are mediated by the formation of free radicals through radiolysis. Irradiation has local effects on tissues. These local effects of irradiation on the bowel are believed to involve a two-stage process which includes both short and long term components. In our study we aimed to investigate the short term effects of Pycnogenol(®) on the healing of colon anastomoses in irradiated bowel. Sixty male Wistar-Albino rats were used in this study. There were three groups: Group I, control group (n = 20); group II which received preoperative irradiation (n = 20); group III which received per oral Pycnogenol(®) before irradiation (n = 20). Only segmeter colonic resection and anastomosis was performed to the control group (Group I). The other groups (Group II, III) underwent surgery on the 5th day after pelvic irradiation. On postoperative days 3 and 7, half of the rats in each group were sacrificed and then relaparotomy was performed. There was no statistical difference between groups with respect to biochemical parameters. Bursting pressure was significantly higher in the Control and Group III compared with the Group II. In conclusion, the present study showed that preoperative irradiation effect negatively on colonic anastomoses in rats by means of mechanical parameters and administration of Pycnogenol(®) preoperatively ameliorates this unfavorable effect. PMID:23791893

  20. Efficacy of potential chemopreventive agents on rat colon aberrant crypt formation and progression.

    PubMed

    Wargovich, M J; Jimenez, A; McKee, K; Steele, V E; Velasco, M; Woods, J; Price, R; Gray, K; Kelloff, G J

    2000-06-01

    We assessed the effects of 78 potential chemopreventive agents in the F344 rat using two assays in which the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon was the measure of efficacy. In both assays ACF were induced by the carcinogen azoxymethane (AOM) in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last AOM injection, animals were evaluated for the number of aberrant crypts detected in methylene blue stained whole mounts of rat colon. In the initiation phase protocol agents were given during the period of AOM administration, whereas in the post-initiation assay the chemopreventive agent was introduced during the last 4 weeks of an 8 week assay, a time when ACF had progressed to multiple crypt clusters. The agents were derived from a priority listing based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. During the initiation phase carboxyl amidoimidazole, p-chlorphenylacetate, chlorpheniramine maleate, D609, diclofenac, etoperidone, eicosatetraynoic acid, farnesol, ferulic acid, lycopene, meclizine, methionine, phenylhexylisothiocyanate, phenylbutyrate, piroxicam, 9-cis-retinoic acid, S-allylcysteine, taurine, tetracycline and verapamil were strong inhibitors of ACF. During the post-initiation phase aspirin, calcium glucarate, ketoprofen, piroxicam, 9-cis-retinoic acid, retinol and rutin inhibited the outgrowth of ACF into multiple crypt clusters. Based on these data, certain phytochemicals, antihistamines, non-steroidal anti-inflammatory drugs and retinoids show unique preclinical promise for chemoprevention of colon cancer, with the latter two drug classes particularly effective in the post-initiation phase of carcinogenesis. PMID:10837003

  1. Exercise associated genes in rat colon mucosa: upregulation of ornithin decarboxylase-1.

    PubMed

    Buehlmeyer, K; Doering, F; Daniel, H; Schulz, T; Michna, H

    2007-05-01

    Epidemiology has revealed that physical activity is an important lifestyle factor that reduces the risk of colon cancer. However, the underlying mechanisms of this protective effect have so far not been defined. The aim of this study was to identify molecular targets of physical activity in rat colon mucosa by employing our voluntary exercise model. Twenty male rats underwent a 12-week exercise program, with 9 additional rats serving as a control group. Running distances, body weights and heart weights as measures of physical adaptations were recorded, and changes in mRNA steady-state levels of marker genes involved in vascularization (VEGF, HIF-1 alpha, ODC-1), apoptosis (Bcl-2, PPAR gamma) and prostaglandin synthesis (COX-2) were determined by qRT-PCR. The four housekeeping genes GAPDH, beta-actin, 18S and ALDA served as reference genes. Recorded running distances showed great inter-individual differences resulting in three different groups of low (L-EX, < 2629 m/night; n=5), moderate (M-EX, 3003 - 7458 m/night; n=10) and high (H-EX, > 8314 m/night; n=5) physical activity. The M-EX and H-EX group revealed significant (p<0.05) adaptive changes with an increase in heart mass per kg body weight and a decrease in mean body weight. Amongst the marker genes studied by mRNA expression analysis only ODC-1 appears to be differentially expressed. Its 1.8-fold increased steady-state mRNA level in the H-EX group suggests that synthesis of polyamines may be increased by physical activity. This new finding could provide a link between extensive physical activity and its protective effects on colon cancer development. PMID:17111318

  2. Escherichia coli K5 capsule expression enhances colonization of the large intestine in the gnotobiotic rat.

    PubMed Central

    Hérias, M V; Midtvedt, T; Hanson, L A; Wold, A E

    1997-01-01

    The role of capsule expression in the capacity of Escherichia coli to colonize in the large intestinal environment was studied in a gnotobiotic rat model. The rats were given perorally a mixture of two mutant strains differing in K5 expression. After 2 weeks, the rats were sacrificed, and subsequently intestinal contents, intestinal mucosae, and mesenteric lymph nodes were homogenized and bacterial numbers were quantified. Two E. coli mutant pairs were used, the first pair (972-998) lacking the O-specific side chain and the second pair (973-997) carrying the O75 lipopolysaccharide. The K5+ mutants established themselves at a higher level than the K5- mutants (10(9) versus 10(6) CFU/g [P < 0.001] for the first pair and 10(9) versus 10(8) CFU/g [P < 0.01] for the second pair, respectively). The results were confirmed by serology showing a K5+ phenotype for practically all isolates. The bacterial population associated with the mucosa was similar to that in the luminal contents with respect to the proportions of the respective mutants, and translocation occurred in numbers proportional to the intestinal population densities of the respective mutants. All mutants were able to express type 1 as well as P fimbriae. After colonization, the expression of P fimbriae remained high whereas only a minority of the isolates expressed type 1 fimbriae. The results suggest that capsule expression and P fimbriae enhance intestinal colonization by E. coli and that these virulence factors, by increasing bacterial densities in the intestine, secondarily increase translocation. PMID:9009309

  3. Modulatory efficacy of rosmarinic acid on premalignant lesions and antioxidant status in 1,2-dimethylhydrazine induced rat colon carcinogenesis.

    PubMed

    Karthikkumar, V; Sivagami, G; Vinothkumar, R; Rajkumar, D; Nalini, N

    2012-11-01

    Colorectal cancer is one of the leading causes of cancer related deaths in Western countries and is becoming increasingly common in Asia. Rosmarinic acid (RA), one of the major components of polyphenol possesses attractive remedial features. The purpose of this study is to investigate the possible chemopreventive mechanism of action of RA against 1,2-dimethylhydrazine (DMH) induced rat colon carcinogenesis by evaluating the circulatory antioxidant status and colonic bacterial enzymes activities. Additionally, we analyzed the aberrant crypt foci (ACF) formation and multiplicity in the colon of experimental groups. Wistar male rats were divided into six groups. Group 1 was control rats, group 2 rats received RA (10 mg/kg b.w., p.o. everyday), rats in groups 3-6 received DMH (20 mg/kg b.w., s.c.) for the first 4 weeks. In addition to DMH, groups 4-6 received 2.5, 5, and 10 mg/kg b.w. RA respectively. The results revealed that supplementation with RA significantly reduced the formation of ACF and ACF multiplicity in DMH treated rats. Moreover RA supplementation prevented the alterations in circulatory antioxidant enzymes and colonic bacterial enzymes activities. Overall, our results showed that all three doses of RA inhibited carcinogenesis, though the effect of the intermediary dose of 5 mg/kg b.w. was more pronounced. PMID:22960260

  4. Only fibres promoting a stable butyrate producing colonic ecosystem decrease the rate of aberrant crypt foci in rats

    PubMed Central

    Perrin, P; Pierre, F; Patry, Y; Champ, M; Berreur, M; Pradal, G; Bornet, F; Meflah, K; Menanteau, J

    2001-01-01

    BACKGROUND—Dietary fibres have been proposed as protective agents against colon cancer but results of both epidemiological and experimental studies are inconclusive.
AIMS—Hypothesising that protection against colon cancer may be restricted to butyrate producing fibres, we investigated the factors needed for long term stable butyrate production and its relation to susceptibility to colon cancer.
METHODS—A two part randomised blinded study in rats, mimicking a prospective study in humans, was performed using a low fibre control diet (CD) and three high fibre diets: starch free wheat bran (WB), type III resistant starch (RS), and short chain fructo-oligosaccharides (FOS). Using a randomised block design, 96 inbred rats were fed for two, 16, 30, or 44 days to determine the period of adaptation to the diets, fermentation profiles, and effects on the colon, including mucosal proliferation on day 44. Subsequently, 36 rats fed the same diets for 44 days were injected with azoxymethane and checked for aberrant crypt foci 30 days later.
RESULTS—After fermentation had stabilised (44 days), only RS and FOS produced large amounts of butyrate, with a trophic effect in the large intestine. No difference in mucosal proliferation between the diets was noted at this time. In the subsequent experiment one month later, fewer aberrant crypt foci were present in rats fed high butyrate producing diets (RS, p=0.022; FOS, p=0.043).
CONCLUSION—A stable butyrate producing colonic ecosystem related to selected fibres appears to be less conducive to colon carcinogenesis.


Keywords: fibre; fermentation; butyrate; colon carcinogenesis; aberrant crypt foci; rat PMID:11115823

  5. Fetal programming of colon cancer in adult rats: correlations with altered neonatal trajectory, circulating IGF-I and IGFPBs, and testosterone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lifelong consumption of soy protein isolate (SPI) reduces the incidence of azoxymethane (AOM)-induced colon tumors in adult male Sprague-Dawley rats. We determined if a maternal SPI diet during pregnancy could protect against colon cancer in progeny. Four groups of male rats were used: a lifetime ...

  6. IGF-1 Gene Expression in Rat Colonic Mucosa After Different Exercise Volumes

    PubMed Central

    Buehlmeyer, Katja; Doering, Frank; Daniel, Hannelore; Petridou, Anatoli; Mougios, Vassilis; Schulz, Thorsten; Michna, Horst

    2007-01-01

    The evidence is increasing for a close link between the insulin/insulin-like growth factor (IGF) system and colon cancer prevention by physical exercise. To reveal exercise-induced alterations in colon mucosa, gene expression of IGF-1 and related genes and serum IGF-1 were investigated. Twenty male Wistar rats performed a 12 week voluntary exercise program. Nine rats served as the control group. Gene expression of IGF-1, IGF-1 receptor (IGF-1R) and IGF-binding protein 3 (IGF-BP3) were quantified by real-time RT-PCR. Circulating IGF-1 was analyzed exercise volume-dependent. Based on 3 distinguished groups with low (L-EX, <2629 m·night-1), medium (M-EX, 3003-7458 m·night-1) and high exercise volume (H-EX, >8314 m·night-1), we observed lower serum IGF-1 levels (P < 0.05) in all exercise groups as compared to the control group and IGF-1 levels declined proportional to the increase in exercise volume. A significant (p < 0.05) positive correlation was found between IGF-1 concentration and body mass (r = 0.50) and a significant negative correlation exists between body mass and exercise volume (r = -0.50). Significant differences in colonic mRNA levels of IGF-1, IGF-1R and IGF-BP3 could not be observed. Based on our data we propose that the exercise as well as the body mass reduction leads to a decrease in circulating IGF-1 and this might represent a prime link to colon cancer prevention. Key pointsThere were significantly lower serum IGF-1 levels in all exercise groups as compared to the control group.GF-1 levels declined proportional to the increase in exercise volume.A significant positive correlation was found between IGF-1 concentration and body mass and a significant negative correlation was found between body mass and exercise volume.Significant differences in colonic mRNA levels of IGF-1, IGF-1R and IGF-BP3 could not be observed. PMID:24149475

  7. IGF-1 Gene Expression in Rat Colonic Mucosa After Different Exercise Volumes.

    PubMed

    Buehlmeyer, Katja; Doering, Frank; Daniel, Hannelore; Petridou, Anatoli; Mougios, Vassilis; Schulz, Thorsten; Michna, Horst

    2007-01-01

    The evidence is increasing for a close link between the insulin/insulin-like growth factor (IGF) system and colon cancer prevention by physical exercise. To reveal exercise-induced alterations in colon mucosa, gene expression of IGF-1 and related genes and serum IGF-1 were investigated. Twenty male Wistar rats performed a 12 week voluntary exercise program. Nine rats served as the control group. Gene expression of IGF-1, IGF-1 receptor (IGF-1R) and IGF-binding protein 3 (IGF-BP3) were quantified by real-time RT-PCR. Circulating IGF-1 was analyzed exercise volume-dependent. Based on 3 distinguished groups with low (L-EX, <2629 m·night(-1)), medium (M-EX, 3003-7458 m·night(-1)) and high exercise volume (H-EX, >8314 m·night(-1)), we observed lower serum IGF-1 levels (P < 0.05) in all exercise groups as compared to the control group and IGF-1 levels declined proportional to the increase in exercise volume. A significant (p < 0.05) positive correlation was found between IGF-1 concentration and body mass (r = 0.50) and a significant negative correlation exists between body mass and exercise volume (r = -0.50). Significant differences in colonic mRNA levels of IGF-1, IGF-1R and IGF-BP3 could not be observed. Based on our data we propose that the exercise as well as the body mass reduction leads to a decrease in circulating IGF-1 and this might represent a prime link to colon cancer prevention. Key pointsThere were significantly lower serum IGF-1 levels in all exercise groups as compared to the control group.GF-1 levels declined proportional to the increase in exercise volume.A significant positive correlation was found between IGF-1 concentration and body mass and a significant negative correlation was found between body mass and exercise volume.Significant differences in colonic mRNA levels of IGF-1, IGF-1R and IGF-BP3 could not be observed. PMID:24149475

  8. EFFECT OF OMEGA-3 FATTY ACID IN THE HEALING PROCESS OF COLONIC ANASTOMOSIS IN RATS

    PubMed Central

    de CASTILHO, Tiago Jacometo Coelho; CAMPOS, Antônio Carlos Ligocki; MELLO, Eneri Vieira de Souza Leite

    2015-01-01

    Background : The use of long-chain polyunsaturated fatty acids has been studied in the context of healing and tissue regeneration mainly due to its anti-inflammatory, immunoregulatory and antioncogenic properties. Previous studies have demonstrated beneficial effects with the use of enteral immunonutrition containing various farmaconutrients such as L-arginine, omega-3, trace elements, but the individual action of each component in the healing of colonic anastomosis remains unclear. Aim : To evaluate the influence of preoperative supplementation with omega-3 fatty acids on the healing of colonic anastomoses of well-nourished rats. Methods : Forty Wistar adult male rats, weighing 234.4±22.3 g were used. The animals were divided into two groups: the control group received for seven days olive oil rich in omega-9 oil through an orogastric tube, while the study group received isocaloric and isovolumetric omega-3 emulsion at a dose of 100 mg/kg/day, also for seven days. Both groups were submitted to two colotomies followed by anastomosis, in the right and left colon, respectively. Parameters evaluated included changes in body weight, anastomotic complications and mortality, as well as maximum tensile strength by using a tensiometer and collagen densitometry at the anastomotic site. Results : There were no differences in body weight or mortality and morbidity between groups. The value of the maximum tensile strength of the control group was 1.9±0.3 N and the study group 1.7±0.2, p=0.357. There was, however, a larger amount of type I collagen deposition in the study group (p=0.0126). The collagen maturation índex was 1.74±0.71 in the control group and 1.67±0.5 in the study group; p=0,719). Conclusions : Preoperative supplementation of omega-3 fatty acid in rats is associated with increased collagen deposition of type I fibers in colonic anastomoses on the 5th postoperative day. No differences were observed in the tensile strength or collagen maturation index. PMID

  9. Interaction of Lactobacillus fermentum BGHI14 with Rat Colonic Mucosa: Implications for Colitis Induction

    PubMed Central

    Lukic, Jovanka; Strahinic, Ivana; Milenkovic, Marina; Golic, Natasa; Kojic, Milan; Topisirovic, Ljubisa

    2013-01-01

    The present study was carried out to test the colonic mucosal response of rats to oral supplementation with Lactobacillus fermentum BGHI14 and to correlate the tissue reaction to trinitrobenzenesulfonate (TNBS)-induced colitis with mucosal barrier alterations caused by bacterial ingestion. An immune cell-mediated reaction of healthy colonic tissue was noticed after bacterial feeding. After prolonged bacterial treatment, the observed reaction had retreated to normality, but the mRNA levels of proinflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α) remained elevated. These data point to the chronic low-grade inflammation that could be caused by long-term probiotic consumption. Although no detrimental effects of bacterial pretreatment were noticed in colitic rats, at least in the acute state of disease, the results obtained in our study point to the necessity of reassessment of existing data on the safety of probiotic preparations. Additionally, probiotic effects in experimental colitis models might depend on time coordination of disease induction with treatment duration. PMID:23851097

  10. Dietary supplementation of an ellagic acid-enriched pomegranate extract attenuates chronic colonic inflammation in rats.

    PubMed

    Rosillo, Maria Angeles; Sánchez-Hidalgo, Marina; Cárdeno, Ana; Aparicio-Soto, Marina; Sánchez-Fidalgo, Susana; Villegas, Isabel; de la Lastra, Catalina Alarcón

    2012-09-01

    Dietary polyphenols present in Punica granatum (pomegranate), such as ellagitannins and ellagic acid (EA) have shown to exert anti-inflammatory and antioxidant properties. This study was designed to evaluate the effects of a dietary EA-enriched pomegranate extract (PE) in a murine chronic model of Cronh's disease (CD). Colonic injury was induced by intracolonic instillation of trinitrobenzensulfonic acid (TNBS). Rats were fed with different diets during 30 days before TNBS instillation and 2 weeks before killing: (i) standard, (ii) PE 250 mg/kg/day, (iii) PE 500 mg/kg/day, (iv) EA 10 mg/kg/day and (v) EA 10 mg/kg/day enriched-PE 250 mg/kg/day. Inflammation response was assessed by histology and MPO activity and TNF-α production. Besides, colonic expressions of iNOS, COX-2, p38, JNK, pERK1/2 MAPKs, IKBα and nuclear p65 NF-κB were studied by western blotting. MPO activity and the TNF-α levels were significantly reduced in dietary fed rats when compared with TNBS group. Similarly, PE and an EA-enriched PE diets drastically decreased COX-2 and iNOS overexpression, reduced MAPKs phosporylation and prevented the nuclear NF-κB translocation. Dietary supplementation of EA contributes in the beneficial effect of PE in this experimental colitis model and may be a novel therapeutic strategy to manage inflammatory bowel disease (IBD). PMID:22677088

  11. Expression of Serotonin Receptors in the Colonic Tissue of Chronic Diarrhea Rats

    PubMed Central

    Zhu, Tong; Qiu, Juanjuan; Wan, Jiajia; Wang, Fengyun; Tang, Xudong; Guo, Huishu

    2016-01-01

    Background/Aims: This study aimed to investigate the difference among the expression of serotonin receptors (5-HT3, 5-HT4, and 5-HT7 receptors) in colonic tissue of chronic diarrhea rats. Materials and Methods: A rat model of chronic diarrhea was established by lactose diet. The expression of 5-HT3, 5-HT4, and 5-HT7 receptors in the colonic tissue was detected using immunohistochemistry, real-time PCR and Western blotting techniques. Results: There is no significant difference on the protein expression of 5-HT3 receptor between the normal group and the chronic diarrhea model group. The mRNA expression of 5-HT3 receptor in the chronic diarrhea model group was significantly lower than that in the normal group (n = 10; P < 0.01). The protein and mRNA expression of 5-HT4 receptor in the chronic diarrhea model group were significantly higher than those in the normal group (n = 10; P < 0.05, P < 0.01). On the contrary, the protein and mRNA expressions of 5-HT7 receptor in the chronic diarrhea model group were significantly decreased compared with the normal group (n = 10; P < 0.01, P < 0.01). Conclusions: The results suggested the receptors of 5-HT4 and 5-HT7 may be involved in inducing diarrhea by lactose diet. PMID:27184643

  12. Radiographic analysis of the effect of dietary fibers on rat colonic transit time

    SciTech Connect

    Lupton, J.R.; Meacher, M.M. )

    1988-11-01

    The effect of different fiber sources on colonic transit time was charted using serial radiographs. Sixty male Sprague-Dawley rats, 10 rats per group, were provided with either a fiber-free control diet or the control diet uniformly diluted to provide 8% dietary fiber from guar, pectin, cellulose, wheat bran, or oat bran. At surgery, radiopaque markers were inserted at defined distances in the mesentary closest to the large bowel. Three weeks postsurgery, the animals were intubated with 0.5 ml of a radiopaque marker, and radiographs were taken at 15-min intervals. Of the two poorly fermented fibers, cellulose was as slow as and wheat bran was faster than the fiber-free controls at five out of the six bowel segments measured. The fermentable fibers (pectin, guar, and oat bran) were fast through some bowel segments and slow through others. This study provides in vivo data on colonic transit time and shows that neither 24-h fecal weight nor total transit time is a good predictor of the rate of transit through particular gut segments.

  13. Effect of gingerol on colonic motility via inhibition of calcium channel currents in rats

    PubMed Central

    Cai, Zheng-Xu; Tang, Xu-Dong; Wang, Feng-Yun; Duan, Zhi-Jun; Li, Yu-Chun; Qiu, Juan-Juan; Guo, Hui-Shu

    2015-01-01

    AIM: To investigate the effect of gingerol on colonic motility and the action of L-type calcium channel currents in this process. METHODS: The distal colon was cut along the mesenteric border and cleaned with Ca2+-free physiological saline solution. Muscle strips were removed and placed in Ca2+-free physiological saline solution, which was oxygenated continuously. Longitudinal smooth muscle samples were prepared by cutting along the muscle strips and were then placed in a chamber. Mechanical contractile activities of isolated colonic segments in rats were recorded by a 4-channel physiograph. Colon smooth muscle cells were dissociated by enzymatic digestion. L-type calcium currents were recorded using the conventional whole-cell patch-clamp technique. RESULTS: Gingerol inhibited the spontaneous contraction of colonic longitudinal smooth muscle in a dose-dependent manner with inhibition percentages of 13.3% ± 4.1%, 43.4% ± 3.9%, 78.2% ± 3.6% and 80.5% ± 4.5% at 25 μmol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L, respectively (P < 0.01). Nifedipine, an L-type calcium channel blocker, diminished the inhibition of colonic motility by gingerol. Gingerol inhibited L-type calcium channel currents in colonic longitudinal myocytes of rats. At a 75 μmol/L concentration of gingerol, the percentage of gingerol-induced inhibition was diminished by nifedipine from 77.1% ± 4.2% to 42.6% ± 3.6% (P < 0.01). Gingerol suppressed IBa in a dose-dependent manner, and the inhibition rates were 22.7% ± 2.38%, 35.77% ± 3.14%, 49.78% ± 3.48% and 53.78% ± 4.16% of control at 0 mV, respectively, at concentrations of 25 μmol/L, 50 μmol/L, 75 μmol/L and 100 μmol/L (P < 0.01). The steady-state activation curve was shifted to the right by treatment with gingerol. The value of half activation was -14.23 ± 1.12 mV in the control group and -10.56 ± 1.04 mV in the 75 μmol/L group (P < 0.05) with slope factors, Ks, of 7.16 ± 0.84 and 7.02 ± 0.93 (P < 0.05) in the control and 75

  14. Characterization of aldosterone-induced potassium secretion in rat distal colon.

    PubMed Central

    Sweiry, J H; Binder, H J

    1989-01-01

    The role of apical and basolateral membranes in aldosterone-induced active potassium (K) secretion in rat distal colon was investigated by measuring mucosal-to-serosal (Jms) and serosal-to-mucosal (Jsm) 42K fluxes (mueq.h-1.cm-2) across isolated stripped mucosa under short-circuit conditions in normal and secondary-hyperaldosterone animals. In normal colons mucosal tetraethylammonium (TEA; 30 mM) or barium (Ba; 5 mM), but not cesium (Cs; 15 mM), reduced Jsm without affecting Jms. In aldosterone animals (a) net K secretion (-0.54 +/- 0.11) was converted to net K absorption (0.63 +/- 0.15) by mucosal TEA, which produced a marked reduction in Jsm (0.82 +/- 0.07) and an increase in Jms (0.35 +/- 0.07). In contrast mucosal Ba resulted in a relatively smaller reduction in JK(sm) without altering JK(ms), whereas mucosal Cs was ineffective; (b) serosal bumetanide or the removal of serosal Na or Cl markedly inhibited JK(sm and abolished net K secretion; and (c) serosal ouabain (1 mM) produced qualitatively similar effects to those of serosal bumetanide. These results demonstrate that (a) normal rat distal colon contains apical TEA- and Ba-sensitive K channels; (b) aldosterone induces TEA-sensitive and Ba-sensitive apical K channels; (c) aldosterone-induced K secretion requires both the Na,K-pump and Na-K-2Cl cotransport for K uptake across the basolateral membrane; and (d) alteration of any of these processes results in inhibition of aldosterone-induced active K secretion simultaneously with stimulation of K absorption. Images PMID:2921323

  15. Chemopreventive effects of Frondanol A5, a Cucumaria frondosa extract, against rat colon carcinogenesis and inhibition of human colon cancer cell growth.

    PubMed

    Janakiram, Naveena B; Mohammed, Altaf; Zhang, Yuting; Choi, Chang-In; Woodward, Carl; Collin, Peter; Steele, Vernon E; Rao, Chinthalapally V

    2010-01-01

    Sea cucumber extracts have been widely used to treat individuals with inflammatory conditions in East Asia. The present study has been designed to test potential colon cancer-preventive properties of Frondanol A5, a glycolipid extract from the sea cucumber, Cucumaria frondosa, using in vivo and in vitro models of colon cancer. Chemopreventive efficacy of Frondanol A5 was evaluated on azoxymethane-induced rat colon carcinogenesis using colonic aberrant crypt foci (ACF) as efficacy marker. At 7 weeks of age, groups of rats (12 per group) were fed the AIN-76A diet, and ACFs were induced by azoxymethane (15 mg/kg body weight). Three days after azoxymethane treatment, rats were fed with the diets containing 0, 150, and 450 ppm of Frondanol A5 and continued on the diets for 8 weeks, at which time ACFs were evaluated. Expression levels of proliferating cell nuclear antigen and p21(WAF1/CIP1) were determined in ACFs. Further, Frondanol A5 (10-120 microg/mL) was studied for its growth-inhibitory and apoptotic effects in the HCT-116 cell line. Dietary administration of 150 and 450 ppm of Frondanol A5 significantly suppressed azoxymethane-induced total colonic ACF formation, approximately 34% to 55% (P < 0.01 to P < 0.0001), and multicrypt aberrant foci (48-68.5%, P < 0.0001) in a dose-dependent manner. ACFs in rats treated with Frondanol A5 showed significant upregulation of p21(WAF1/CIP1) and downregulation of proliferating cell nuclear antigen compared with control group. Frondanol A5 showed growth inhibition at S and G(2)-M phase with a decrease in Cdc25c and an increase in p21(WAF1/CIP) with significant apoptosis associated with H2AX phosphorylation and caspase-2 cleavage in HCT116 cells. Overall, Frondanol A5 exhibits potential chemopreventive properties for colon carcinogenesis, which suggests further development of this sea cucumber extract. PMID:20051375

  16. Modulation of distal colonic epithelial barrier function by dietary fibre in normal rats

    PubMed Central

    Mariadason, J; Catto-Smith, A; Gibson, P

    1999-01-01

    BACKGROUND—Dietary fibre influences the turnover and differentiation of the colonic epithelium, but its effects on barrier function are unknown. 
AIMS—To determine whether altering the type and amount of fibre in the diet affects paracellular permeability of intestinal epithelium, and to identify the mechanisms of action. 
METHODS—Rats were fed isoenergetic low fibre diets with or without supplements of wheat bran (10%) or methylcellulose (10%), for four weeks. Paracellular permeability was determined by measurement of conductance and 51Cr-EDTA flux across tissue mounted in Ussing chambers. Faecal short chain fatty acid (SCFA) concentrations were assessed by gas chromatography, epithelial kinetics stathmokinetically, and mucosal brush border hydrolase activities spectrophotometrically. 
RESULTS—Body weight was similar across the dietary groups. Conductance and 51Cr-EDTA flux were approximately 25% higher in animals fed no fibre, compared with those fed wheat bran or methylcellulose in the distal colon, but not in the caecum or jejunum. Histologically, there was no evidence of epithelial injury or erosion associated with any diet. The fibres exerted different spectra of effects on luminal SCFA concentrations and pH, and on mucosal indexes, but both bulked the faeces, were trophic to the epithelium, and stimulated expression of a marker of epithelial differentiation. 
CONCLUSIONS—Both a fermentable and a non-fermentable fibre reduce paracellular permeability specifically in the distal colon, possibly by promoting epithelial cell differentiation. The mechanisms by which the two fibres exert their effects are likely to be different. 

 Keywords: colon; differentiation; epithelium; fibre; paracellular permeability; proliferation PMID:10026327

  17. Remodeling of the rat distal colon in diabetes: function and ultrastructure.

    PubMed

    Siegman, Marion J; Eto, Masumi; Butler, Thomas M

    2016-01-15

    This study seeks to define and explain remodeling of the distal colon in the streptozotocin (STZ)-treated rat model of diabetes through analysis of resting and active length dependence of force production, chemical composition, and ultrastructure. Compared with untreated controls, the passive stiffness on extension of the diabetic muscle is high, and active force produced at short muscle lengths is amplified but is limited by an internal resistance to shortening. The latter are accounted for by a significant increase in collagen type 1, with no changes in types 3 and 4. In the diabetic colon, ultrastructural studies show unique, conspicuous pockets of collagen among muscle cells, in addition to a thickened basement membrane and an extracellular space filled with collagen fibers and various fibrils. Measurements of DNA and total protein content revealed that the diabetic colon underwent hypertrophy, along with a proportional increase in actin and myosin contents, with no change in the actin-to-myosin ratio. Active force production per cross-sectional area was not different in the diabetic and normal muscles, consistent with the proportionality of changes in contractile proteins. The stiffness and the limit to shortening of the diabetic colon were significantly reduced by treatment with the glycation breaker alagebrium chloride (ALT-711), with no change in collagen contents. Functionally, this study shows that, in diabetes, the production of collagen type 1 and glycation increase stiffness, which limits distensibility on filling and limits shortening and expulsion of contents, both of which can be alleviated by treatment with ALT-711. PMID:26561639

  18. Collagen deposition and mechanical strength of colon anastomoses and skin incisional wounds of rats.

    PubMed

    Oxlund, H; Christensen, H; Seyer-Hansen, M; Andreassen, T T

    1996-11-01

    The mechanical strength development of healing wounds depends on the formation of collagen fibrils bridging the wound cleft. A considerable deposition, degradation, and remodeling of these fibrils takes place influencing the mechanical strength of the healing wounds. A method for studies of wound collagen metabolism in vivo is delineated, enabling determination of collagen deposition per hour in rat colon anastomoses and skin incisional wounds. Labeled proline was incorporated into wound collagen with a flooding dose of unlabeled proline, reducing errors introduced by proline recycling and proline de novo synthesis. The mechanical strength was determined by a materials testing machine. In both colon anastomoses and skin wounds a substantial increase in collagen deposition was observed at Day 2, reached a maximum at Day 6, and was still relatively high at Day 12 during the remodeling of collagen fibers in the wound cleft. The collagen deposition in colon anastomoses at Day 6, however, was 10-fold higher compared with that of the skin incisional wounds. The time course of the collagen deposition was much alike in colon anastomoses and skin incisional wounds reaching a maximum at Day 6. The mechanical strength of these two rather different types of wounds was increased correspondingly and to the same level during the 1st week of healing. The measurements of collagen deposition, collagen content, and biomechanical strength indicated a substantial turnover of newly synthesized and deposited collagen during the early phases of wound healing. On the basis of this, it seems obvious that even small disturbances to the balance between collagen synthesis, deposition, collagen cross-linking, and collagen degradation/remodeling may result in defective wound healing. PMID:8954827

  19. Acute effects of morphine and opioid peptides on the motility and responses of rat colon to electrical stimulation.

    PubMed Central

    Gillan, M. G.; Pollock, D.

    1980-01-01

    1 Morphine and leucine- and methionine-enkephalins inhibited the contractile response of the pithed rat colon to electrical stimulation of the spinal motor outflows and inhibited motor responses of the isolated colon to field stimulation. 2 Morphine and the opioid peptides also had an excitatory action in the colon. In the pithed rat, opiates caused regular fluctuations in intracolonic pressure and in the isolated colon, caused regular waves of contraction. This excitatory response was produced by low concentrations of the enkephalins (2 X 10(-8) M, 2 X 10(-9) M), was stereospecific and was antagonized by naloxone. 3 Opiate-induced contractions in the isolated colon were inhibited by catecholamines, adenine nucleotides and by phosphodiesterase inhibitors. These contractions were unaffected by ergotamine and tolazoline, or by propranolol. 4 The excitatory action of opiates in the isolated colon was not antagonized and usually was potentiated by atropine, (+)-tubocurarine and hexamethonium. In the absence of opiates, these drugs also produced similar waves of contraction, which were unaffected by naloxone. 5 Opiate-induced contractions occurred in colon rendered unresponsive to 5-hydroxytryptamine (5-HT) and these contractions were potentiated by the 5-HT antagonist, lysergic acid diethylamide, which, when administered alone, caused similar contractions. The 5-HT antagonist, cyproheptadine, inhibited opiate-induced contractions but was non-specific, since it also inhibited responses of the colon to carbachol and KC1. 6 Opiate-induced contractions were unaffected by procaine and were potentiated by tetrodotoxin. Both of these drugs, when administered alone, produced waves of contractions, which were similar to those produced by opiates but were unaffected by naloxone. 7 Contractions produced in the isolated colon either by opiates, atropine or (+)-tubocurarine, or any combination of these drugs, were inhibited by field stimulation applied at the peak of a wave of

  20. High dietary intake of sodium selenite does not affect gene mutation frequency in rat colon and liver.

    PubMed

    Zeng, Huawei; Uthus, Eric O; Ross, Sharon A; Davis, Cindy D

    2009-10-01

    Our previous studies have shown that selenium (Se) is protective against dimethylhydrazine (DMH)-induced preneoplastic colon cancer lesions, and protection against DNA damage has been hypothesized to be one mechanism for the anticancer effect of Se. The present study was designed to determine whether dietary selenite affects somatic mutation frequency in vivo. We used the Big Blue transgenic model to evaluate the in vivo mutation frequency of the cII gene in rats fed either a Se-deficient (0 microg Se/g diet) or Se-supplemented diet (0.2 or 2 microg Se/g diet; n = 3 rats/diet in experiment 1 and n = 5 rats/group in experiment 2) and injected with DMH (25 mg/kg body weight, i.p.). There were no significant differences in body weight between the Se-deficient and Se-supplemented (0.2 or 2 microg Se/g diet) rats, but the activities of liver glutathione peroxidase and thioredoxin reductase and concentration of liver Se were significantly lower (p < 0.0001) in Se-deficient rats compared to rats supplemented with Se. We found no effect of dietary Se on liver 8-hydroxy-2'-deoxyguanosine. Gene mutation frequency was significantly lower in liver (p < 0.001) than that of colon regardless of dietary Se. However, there were no differences in gene mutation frequency in DNA from colon mucosa or liver from rats fed the Se-deficient diet compared to those fed the Se-supplemented (0.2 or 2 microg Se/g diet) diet. Although gene mutations have been implicated in the etiology of cancer, our data suggest that decreasing gene mutation is not likely a key mechanism through which dietary selenite exerts its anticancer action against DMH-induced preneoplastic colon cancer lesions in a Big Blue transgenic rat model. PMID:19263001

  1. Pomegranate (Punica granatum) peel extract efficacy as a dietary antioxidant against azoxymethane-induced colon cancer in rat.

    PubMed

    Waly, Mostafa I; Ali, Amanat; Guizani, Nejib; Al-Rawahi, Amani S; Farooq, Sardar A; Rahman, Mohammad S

    2012-01-01

    Functional foods include antioxidant nutrients which may protect against many human chronic diseases by combating reactive oxygen species (ROS) generation. The purpose of the present study was to investigate the protective effect of pomegranate peel extract (PPE) on azoxymethane (AOM)-induced colon tumors in rats as an in vivo experimental model. Forty Sprague-Dawley rats (4 weeks old) were randomly divided into 4 groups containing 10 rats per group, and were treated with either AOM, PPE, or PPE plus AOM or injected with 0.9% physiological saline solution as a control. At 8 weeks of age, the rats in the AOM and PPE plus AOM groups were injected with 15 mg AOM/kg body weight, once a week for two weeks. After the last AOM injection, the rats were continuously fed ad-libitum their specific diets for another 6 weeks. At the end of the experiment (i.e. at the age of 4 months), all rats were killed and the colon tissues were examined microscopically for lesions suspected of being preneoplastic lesions or tumors as well as for biochemical measurement of oxidative stress indices. The results revealed a lower incidence of aberrant crypt foci in the PPE plus AOM administered group as compared to the AOM group. In addition, PPE blocked the AOM-induced impairment of biochemical indicators of oxidative stress in the examined colonic tissue homogenates. The results suggest that PPE can partially inhibit the development of colonic premalignant lesions in an AOM-induced colorectal carcinogenesis model, by abrogating oxidative stress and improving the redox status of colonic cells. PMID:23098515

  2. Cellular localization of guanylin and uroguanylin mRNAs in human and rat duodenal and colonic mucosa.

    PubMed

    Brenna, Øystein; Furnes, Marianne W; Munkvold, Bjørn; Kidd, Mark; Sandvik, Arne K; Gustafsson, Björn I

    2016-08-01

    Guanylin (GUCA2A/Guca2a/GN) and uroguanylin (GUCA2B/Guca2b/UGN) are expressed in the gastrointestinal tract and have been implicated in ion and fluid homeostasis, satiety, abdominal pain, growth and intestinal barrier integrity. Their cellular sources are debated and include goblet cells, entero-/colonocytes, enteroendocrine (EE) cells and tuft cells. We therefore investigated the cellular sources of GN and UGN mRNAs in human and rat duodenal and colonic epithelium with in situ hybridization (ISH) to determine co-expression with Chromogranin A (CHGA/Chga/CgA; enterochromaffin [EC] cells), defensin alpha 6 (DEFA6/Defa6; Paneth cells), mucin 2 (MUC2/Muc2; goblet cells) and selected tuft cell markers. GUCA2A/Guca2a expression was localized to goblet cells and colonocytes in human and rat colon. In human duodenum, GUCA2A was expressed in Paneth cells and was scarce in villous epithelial cells. In rat duodenum, Guca2a was only localized to goblet cells. Guca2b was focally expressed in rat colon. In human and rat duodenum and in human colon, GUCA2B/Guca2b was expressed in dispersed solitary epithelial cells, some with a tuft cell-like appearance. Neither GUCA2A nor GUCA2B were co-expressed with CHGA in human duodenal cells. Consequently, EC cells are probably not the major source of human GN or UGN but other EE cells as a source of GN or UGN are not entirely excluded. No convincing overlap with tuft cell markers was found. For the first time, we demonstrate the cellular expression of GUCA2B in human duodenum. The specific cellular distribution of both GN and UGN differs between duodenum and colon and between human and rat intestines. PMID:27044258

  3. Fibrinogen and thrombin concentrations are critical for fibrin glue adherence in rat high-risk colon anastomoses

    PubMed Central

    Buen, Eliseo Portilla-de; Orozco-Mosqueda, Abel; Leal-Cortés, Caridad; Vázquez-Camacho, Gonzalo; Fuentes-Orozco, Clotilde; Alvarez-Villaseñor, Andrea Socorro; Macías-Amezcua, Michel Dassaejv; González-Ojeda, Alejandro

    2014-01-01

    OBJECTIVE: Fibrin glues have not been consistently successful in preventing the dehiscence of high-risk colonic anastomoses. Fibrinogen and thrombin concentrations in glues determine their ability to function as sealants, healers, and/or adhesives. The objective of the current study was to compare the effects of different concentrations of fibrinogen and thrombin on bursting pressure, leaks, dehiscence, and morphology of high-risk ischemic colonic anastomoses using fibrin glue in rats. METHODS: Colonic anastomoses in adult female Sprague-Dawley rats (weight, 250-350 g) treated with fibrin glue containing different concentrations of fibrinogen and thrombin were evaluated at post-operative day 5. The interventions were low-risk (normal) or high-risk (ischemic) end-to-end colonic anastomoses using polypropylene sutures and topical application of fibrinogen at high (120 mg/mL) or low (40 mg/mL) concentrations and thrombin at high (1000 IU/mL) or low (500 IU/mL) concentrations. RESULTS: Ischemia alone, anastomosis alone, or both together reduced the bursting pressure. Glues containing a low fibrinogen concentration improved this parameter in all cases. High thrombin in combination with low fibrinogen also improved adherence exclusively in low-risk anastomoses. No differences were detected with respect to macroscopic parameters, histopathology, or hydroxyproline content at 5 days post-anastomosis. CONCLUSIONS: Fibrin glue with a low fibrinogen content normalizes the bursting pressure of high-risk ischemic left-colon anastomoses in rats at day 5 after surgery. PMID:24714834

  4. Chemotherapeutic effect of Berberis integerrima hydroalcoholic extract on colon cancer development in the 1,2-dimethyl hydrazine rat model.

    PubMed

    Malayeri, Mohammad R Mohammadi; Dadkhah, Abolfazl; Fatemi, Faezeh; Dini, Salome; Torabi, Fatemeh; Tavajjoh, Mohammad M; Rabiei, Javad

    2016-01-01

    The aim of this study was to investigate the efficacy of a Berberis integerrima hydroalcoholic extract as a chemotherapeutic agent in colon carcinogenesis in the rat induced by 1,2-dimethyl hydrazine (DMH). Male Wistar rats were divided into five groups: a negative control group without DMH treatment; a control group injected DMH (20 mg/kg b.w); two groups receiving B. integerrima extract (50 and 100 mg/kg b.w), concomitant with injected DMH, as chemotherapeutic groups; a positive control group receiving 5-fluorouracil (5-FU) along with DMH. The effects of the extracts were determined by assessment of hepatic malondialdehyde (MDA), glutathione (GSH), ferric reducing ability of plasma (FRAP), and the activities of hepatic glutathione S-transferase and cytochrome P450 (GST and CYP450). Additionally, colon tissues were assessed for colonic β-catenin and histopathological analysis. In DMH-treated rats, the extracts partially normalized the levels of FRAP, CYP450, β-catenin, and GST. Likewise, formation of aberrant crypt foci (ACF) in colon tissue of DMH-treated was reduced by the extracts. Thus, the extracts possess chemotherapeutic activity against colon carcinogenesis. PMID:27232632

  5. P21 and CEA expression and AgNOR counts in dimethylhydrazine-induced colon carcinoma in rats

    PubMed Central

    Zhang, Zhi-Gang; Wu, Jing-Ying; Fu, Xiang-Dong; Gu, Da-Kun; Fang, Fang

    1997-01-01

    AIM: To study P21 and carcinoembryonic antigen (CEA) expression and to measure argyrophilic nucleolar organizer region (AgNOR) counts in various lesions of colonic mucosa and the mechanism of carcinogenesis. METHODS: Thirty-eight male Wistar rats were injected with dimethylhydrazine (DMH) once a week for 25 wk. P21 and CEA expression was detected by immunohistochemical methods, and AgNOR was counted by silver staining paraffin sections from various colonic lesions. RESULTS: The incidence of colonic carcinoma in DMH-treated rats was 71.05% (27/38), and lymph node metastasis occurred in six rats. Immunohistochemical studies showed that P21 was primarily expressed in dysplasia and carcinomas, while CEA was expressed in carcinomas and metastatic tumors. AgNOR counts were higher in dysplasia and carcinomas. There were significant differences in P21 and CEA expression between benign and malignant lesions (P < 0.05). The difference in AgNOR counts was also significant between normal and dysplastic tissues, and between dysplasia and malignant lesions (P < 0.05). CONCLUSION: Dysplasia is a premalignant change of colonic carcinoma. The detection of P21 via immunohistochemistry and AgNOR counting may be an important clinical screening technique for colon carcinoma and premalignant lesions.

  6. Effect of YNS-15P, a new alpha-2 adrenoceptor antagonist, on stress-stimulated colonic propulsion in rats.

    PubMed

    Yamamoto, O; Niida, H; Tajima, K; Shirouchi, Y; Kyotani, Y; Ueda, F; Kise, M; Kimura, K

    1998-11-01

    We studied effects of a novel alpha-2 adrenoceptor antagonist, YNS-15P (N-[(2R,11bS)-9-methoxy-1,3,4,6,7, 11b-hexahydro-2H-benzoquinolizin-2-yl]-N-methylmethanesulfonami de hydrochloride), on colonic propulsion stimulated by wrap-restraint stress (WRS) or bethanechol, on normal colonic propulsion and on diarrhea induced by castor oil in rats. Alpha-2 adrenoceptor antagonists, rauwolscine and RX821002, decreased the increase in the number and weight of fecal pellets induced by WRS. YNS-15P also inhibited WRS-stimulated fecal excretion in a dose-dependent manner. A 5-hydroxytryptamine3 receptor antagonist, granisetron, trimebutine and diazepam, but not a 5-hydroxytryptamine4 receptor antagonist, GR113808, significantly inhibited WRS-stimulated fecal excretion. YNS-15P inhibited WRS-stimulated colonic transit in a dose-dependent manner. However, YNS-15P had no significant effect on normal fecal excretion and colonic transit or on bethanechol-stimulated fecal excretion. YNS-15P also failed to inhibit castor-oil-induced diarrhea. These results indicate that YNS-15P selectively inhibits WRS-stimulated colonic propulsion, and that alpha-2 adrenoceptors may be involved in stress-induced colonic motor dysfunction in fed rats. PMID:9808698

  7. Region-specific changes in mitochondrial D-loop in aged rat CNS.

    PubMed

    McInerny, Simone C; Brown, Amanda L; Smith, Doug W

    2009-05-01

    Impaired mitochondrial oxidative phosphorylation (OXPHOS) is considered a cause of aging. A reduction in mitochondrial DNA (mtDNA) replication and/or transcription may contribute to this OXPHOS diminution. Impairments in the displacement (D) loop, or non-coding, region of the mitochondrial genome, or accumulation of mtDNA mutations, may affect mtDNA replication and transcription. We determined the effects of age on the D-loop and on mtDNA deletion mutations in the spinal cord, medulla, midbrain, cerebellum, striatum, and cerebral cortex of Fischer 344 rats. D-loop, 7S DNA levels were reduced by 3-fold in striatum, 2.5-fold in cortex, and 2-fold in the spinal cord of older animals. We did not detect a population of mtDNA affected by the most prevalent known (ND4-containing) deletions, indicating they do not comprise a significant portion of total mtDNA. However, we detected an age-related and region-specific increase in the common deletion, which comprised 0.0003-0.0007% of total mtDNA. Mitochondrial genome copy number varied between regions, in addition to an overall 18% decrease with age across the whole brain. These results suggest the age-related decline in OXPHOS may be related to a reduction in D-loop function. PMID:19428453

  8. Activation of prostaglandin EP receptors by lubiprostone in rat and human stomach and colon

    PubMed Central

    Bassil, A K; Borman, R A; Jarvie, E M; McArthur-Wilson, R J; Thangiah, R; Sung, E Z H; Lee, K; Sanger, G J

    2008-01-01

    Background and purpose: Lubiprostone (Amitiza), a possible ClC-2 channel opener derived from prostaglandin E1 and indicated for the treatment of constipation, increases chloride ion transport and fluid secretion into the intestinal lumen. As lubiprostone may also directly modulate gastrointestinal motility, we investigated its actions and the possible involvement of prostaglandin EP receptor activation on rat and human isolated gastrointestinal preparations. Experimental approach: Rat and human isolated preparations were mounted in tissue baths for isometric recording. The effects of lubiprostone on muscle tension and on electrically stimulated, neuronal contractions were investigated in the absence and presence of EP receptor antagonists. Key results: In rat and human stomach longitudinal muscle, lubiprostone induced a contraction (pEC50 of 7.0±0.0, n=4 and 6.4±0.2, n=3, respectively), which was inhibited by pretreatment with the EP1 receptor antagonist, EP1A 300 nM (pEC50 reduced to 6.2±0.2, n=6), but not by the EP3 or EP4 receptor antagonists (L-798106 and GW627368X, respectively, 1 μM, P>0.05). Lubiprostone also reduced electrically stimulated, neuronal contractions in rat and human colon circular muscle preparations (pIC50 of 8.9±0.4, n=7 and 8.7±0.9, n=6, respectively), an effect mediated pre-junctionally. This effect was reduced by the EP4 receptor antagonist (pIC50 of 6.7±1.1, n=7 and 7.7±0.4, n=6, respectively) but not by EP1 or EP3 receptor antagonists. Conclusions and implications: In rats and humans, lubiprostone contracts stomach longitudinal muscle and inhibits neuronally mediated contractions of colon circular muscle. Experiments are now needed to determine if this additional activity of lubiprostone contributes to its clinical efficacy and/or side-effect profile. PMID:18332851

  9. DIETARY ARSENITE AFFECTS DIMETHYLHYDRAZINE (DMH)-INDUCED ABERRANT CRYPT FORMATION IN COLON AND GLOBAL DNA METHYLATION IN LIVER OF RATS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous work has shown that arsenic (As) affects methionine metabolism. Alterations in methionine metabolism can affect cancer processes. To determine the effect of dietary As on DMH-induced aberrant crypt formation in colon Fisher-344 male, weanling rats (N=20/group) were fed diets containing 0, 0...

  10. A mathematical model of rat proximal tubule and loop of Henle.

    PubMed

    Weinstein, Alan M

    2015-05-15

    Proximal tubule and loop of Henle function are coupled, with proximal transport determining loop fluid composition, and loop transport modulating glomerular filtration via tubuloglomerular feedback (TGF). To examine this interaction, we begin with published models of the superficial rat proximal convoluted tubule (PCT; including flow-dependent transport in a compliant tubule), and the rat thick ascending Henle limb (AHL). Transport parameters for this PCT are scaled down to represent the proximal straight tubule (PST), which is connected to the thick AHL via a short descending limb. Transport parameters for superficial PCT and PST are scaled up for a juxtamedullary nephron, and connected to AHL via outer and inner medullary descending limbs, and inner medullary thin AHL. Medullary interstitial solute concentrations are specified. End-AHL hydrostatic pressure is determined by distal nephron flow resistance, and the TGF signal is represented as a linear function of end-AHL cytosolic Cl concentration. These two distal conditions required iterative solution of the model. Model calculations capture inner medullary countercurrent flux of urea, and also suggest the presence of an outer medullary countercurrent flux of ammonia, with reabsorption in AHL and secretion in PST. For a realistically strong TGF signal, there is the expected homeostatic impact on distal flows, and in addition, a homeostatic effect on proximal tubule pressure. The model glycosuria threshold is compatible with rat data, and predicted glucose excretion with selective 1Na(+):1glucose cotransporter (SGLT2) inhibition comports with observations in the mouse. Model calculations suggest that enhanced proximal tubule Na(+) reabsorption during hyperglycemia is sufficient to activate TGF and contribute to diabetic hyperfiltration. PMID:25694479

  11. Vitamin B-12 deficiency induces anomalies of base substitution and methylation in the DNA of rat colonic epithelium.

    PubMed

    Choi, Sang-Woon; Friso, Simonetta; Ghandour, Haifa; Bagley, Pamela J; Selhub, Jacob; Mason, Joel B

    2004-04-01

    Derangements of one-carbon metabolism can directly affect the integrity of the genome by producing inappropriate uracil insertion into DNA and by altering patterns of DNA methylation. Vitamin B-12, a one-carbon nutrient, serves as a cofactor in the synthesis of precursors of biological methylation and in nucleotide synthesis. We therefore examined whether vitamin B-12 deficiency can induce these molecular anomalies in the colonic mucosa of rats. Weanling male Sprague-Dawley rats (n = 30) were divided into 2 groups and fed either a vitamin B-12-deficient diet or a similar diet containing adequate amounts of the vitamin. Rats from each group were killed at 6 and 10 wk. Uracil misincorporation into DNA was measured by GC/MS and genomic DNA methylation was measured by LC/MS. Plasma vitamin B-12 concentrations in deficient rats were below detectable limits at 6 and 10 wk; in control rats, concentrations were 0.46 +/- 0.07 and 0.42 +/- 0.10 nmol/L at those times. Although the colon total folate concentration did not differ between the groups, the proportion that was methylfolate was marginally greater in the deficient rats at 10 wk (P = 0.05) compared with control, consistent with the "methylfolate trap" that develops during vitamin B-12 deficiency. After 10 wk, the colonic DNA of the deficient rats displayed a 35% decrease in genomic methylation and a 105% increase in uracil incorporation (P < 0.05). This vitamin B-12-deficient diet, which was of insufficient severity to cause anemia or illness, created aberrations in both base substitution and methylation of colonic DNA, which might increase susceptibility to carcinogenesis. PMID:15051821

  12. Local exposure system for rats head using a figure-8 loop antenna in 1500-MHz band.

    PubMed

    Arima, Takuji; Watanabe, Hiroshi; Wake, Kanako; Masuda, Hiroshi; Watanabe, Soichi; Taki, Masao; Uno, Toru

    2011-10-01

    Cellular phones are used in the vicinity of the human head, resulting in localized exposure to this part of the body. To simulate exposure during cellular phone use, microwave energy absorption should be focused within the head region of laboratory animals. In this paper, we developed an exposure system using a figure-8 loop antenna to permit localized exposure of a rat head to 1500-MHz microwave fields, simulating human head exposure to cellular phones. We have numerically estimated the specific absorption rate (SAR) in a rat exposed to microwave fields via our new exposure system. The high ratio of SAR averaged over the target tissue (i.e., the brain) to that averaged over the whole body suggests that the figure-8 antenna can realize greater localized exposure than the previously used exposure system. We have also confirmed the effectiveness of our proposed system experimentally. PMID:21216701

  13. Interaction of dietary fat and route of carcinogen administration on 1,2-dimethylhydrazine-induced colon tumorigenesis in rats.

    PubMed

    Locniskar, M; Nauss, K M; Kaufmann, P; Newberne, P M

    1985-03-01

    Since the results of an earlier study indicating no effect of dietary fat on dimethylhydrazine (DMH)-induced colon cancer in rats differed from those of other investigators, the present study was initiated to determine if the modulating effect of fat intake on colon tumorigenesis was dependent on the route of DMH administration. Male weanling Sprague-Dawley rats (160) were fed one of two nutritionally balanced diets containing 5% or 24% corn oil (CO). Following 3 weeks adaptation to their respective diets, 40 rats from each diet group were treated with five doses of DMH (30 mg/kg) by intragastric (i.g.) gavage or subcutaneous (s.c.) injection, over a 3 week period. Rats were sacrificed when they showed clinical signs of colon tumor and surviving animals were killed 51 weeks after the initial DMH treatment. The cumulative probability of death with colon carcinoma did not differ between the dietary or treatment groups. There was no effect of route of administration or dietary fat on total intestinal tumor incidence. The number of rats with colon carcinoma was: 5% CO.IG = 25; 24% CO.IG = 27; 5% CO.SC = 23; 24% CO.SC = 19. Polypoid tumor incidence was significantly higher in the 24% CO.SC group (12/40) compared to the 5% CO.SC group (3/40) (Chi-squared = 5.25; p less than 0.03) while sessile tumor incidence was the inverse. Marginally significant differences in tumor morphology were noted between the IG groups. PMID:3978750

  14. Modulatory effect of troxerutin on biotransforming enzymes and preneoplasic lesions induced by 1,2-dimethylhydrazine in rat colon carcinogenesis.

    PubMed

    Vinothkumar, Rajamanickam; Vinoth Kumar, Rajenderan; Sudha, Mani; Viswanathan, Periyaswamy; Balasubramanian, Thangavel; Nalini, Namasivayam

    2014-02-01

    Colon cancer is the third most global oncologic problem faced by medical fraternity. Troxerutin, a flavonoid present in tea, coffee, cereal grains, and a variety of fruits and vegetables, exhibits various pharmacological and biological activities. This study was carried out to investigate the effect of troxerutin on xenobiotic metabolizing enzymes, colonic bacterial enzymes and the development of aberrant crypt foci (ACF) during 1,2-dimethylhydrazine (DMH) induced experimental rat colon carcinogenesis. Male albino Wistar rats were randomly divided into six groups. Group 1 served as control. Group 2 received troxerutin (50 mg/kg b.w., p.o. every day) for 16 weeks. Groups 3-6 received subcutaneous injections of DMH (20 mg/kg b.w.) once a week, for the first four weeks. In addition, groups 4-6 received different doses of troxerutin (12.5, 25, 50 mg/kg b.w., p.o. every day respectively) along with DMH injections. Our results reveal that DMH treated rats exhibited elevated activities of phase I enzymes such as cytochrome P450, cytochrome b5, cytochrome P4502E1, NADPH-cytochrome P450 reductase and NADH-cytochrome b5 reductase and reduced activities of phase II enzymes such as glutathione-S-transferase (GST), DT-diaphorase (DTD) and uridine diphospho glucuronyl transferase (UDPGT) in the liver and colonic mucosa of control and experimental rats. Furthermore, the activities of fecal and colonic mucosal bacterial enzymes, such as β-glucronidase, β-glucosidase, β-galactosidase and mucinase were found to be significantly higher in DMH alone treated rats than those of the control rats. On supplementation with troxerutin to DMH treated rats, the alterations in the activities of the biotransforming enzymes, bacterial enzymes and the pathological changes were significantly reversed, the effect being more pronounced when troxerutin was supplemented at the dose of 25 mg/kg b.w. Thus troxerutin could be considered as a good chemopreventive agent against the formation of

  15. Comparison of immune status and 1,2-dimethylhydrazine induced tumorigenesis in brown--Norway and Fischer rats. Emphasis on splenic and colonic lymphocyte function.

    PubMed

    Locniskar, M; Nauss, K M; Kauffman, P; Newberne, P M

    1985-01-01

    Sym 1,2-dimethylhydrazine (DMH)-induced colon tumorigenesis was studied in immunologically different strains of rat: the Brown--Norway which is known to be immunologically a low-responder and the Fischer a high-responder. Brown--Norway rats received a total dose of 75, 150 or 225 mg DMH/kg or vehicle and Fischer rats received 150 mg DMH/kg or vehicle over a 3-week period. Rats were killed 5 months after the final treatment. Lymphocytes were isolated from the spleen and colon from rats treated with 150 mg DMH/kg or vehicle. Natural killer (NK) cell activity and the autologous mixed lymphocyte response (AMLR) as well as colon tumor incidence were compared between the two strains. Splenic and colonic intraperithelial lymphocytes (IEL) from the Brown--Norway strain demonstrated low NK activity and reduced splenic T lymphocyte proliferation in response to autologous non-T lymphocytes. As well, colonic lamina propria lymphocyte (LPL) proliferation was low and Brown--Norway rats had a low incidence of DMH-induced colon neoplasms (7%). In comparison, the Fischer rats had more effective splenic and IEL NK killing, enhanced splenic AMLR, enhanced LPL proliferation and a higher incidence of colon tumors (20%). PMID:3871659

  16. Silibinin modulates caudal-type homeobox transcription factor (CDX2), an intestine specific tumor suppressor to abrogate colon cancer in experimental rats.

    PubMed

    Sangeetha, N; Nalini, N

    2015-01-01

    To authenticate the colon cancer preventive potential of silibinin, the efficacy of silibinin needs to be tested by evaluating an organ-specific biomarker. The aim of this study was to evaluate the impact of silibinin on the colonic expression of the caudal-type homeobox transcription factor (CDX2) an intestine specific tumor suppressor gene and its downstream targets in the colon of rats challenged with 1,2 dimethyl hydrazine (DMH). Rats of groups 1 and 2 were treated as control and silibinin control. Rats under groups 3 and 4 were given DMH (20 mg/kg body weight (b.w.) subcutaneously) once a week for 15 consecutive weeks from the 4th week of the experimental period. In addition, group 4 rats alone were treated with silibinin (50 mg/kg b.w. per os) everyday throughout the study period of 32 weeks. Histological investigation and messenger RNA and protein expression studies were performed in the colonic tissues of experimental rats. Findings of the study revealed that DMH administration significantly decreased the expression of CDX2 and Guanylyl cyclase C (GCC) in the colon of experimental rats. Further the decreased levels of CDX2 protein, colonic mucin content, and increased number of mast cells in the colon of DMH alone-administered rats reflects the onset of carcinogenesis. The pathological changes caused due to CDX2 suppression were attenuated by silibinin supplementation. PMID:24740923

  17. Natural killer cell activity and autologous mixed lymphocyte response of splenic, mesenteric lymph node, and colonic lymphocytes during DMH-induced colon carcinogenesis in the rat.

    PubMed

    Locniskar, M; Nauss, K M; Newberne, P M

    1987-07-01

    Two in vitro models of immune surveillance were used to examine the immune status of the gut-associated lymphoid tissue, mesenteric lymph nodes, and spleen during the early stages of 1,2-dimethylhydrazine (DMN)-induced colon tumorigenesis. DMH- and vehicle-treated Fischer rats were sacrificed at one of three time points: one week, two months, or five months after cessation of treatment. Colonic, lymph node, and splenic natural killer cell cytolytic activity toward YAC-1 tumor targets and T-cell response to autologous Ia-induced blastogenesis were measured at each time point. We found little change in natural killer cell activity or T-cell proliferation induced by autologous Ia gene products at these time periods. PMID:2954798

  18. Colonic cell growth and mucin degradation in rats fed diets containing various levels of beta-carotene with and without dietary agar.

    PubMed

    Hwa, S H; Shiau, S Y

    1993-06-01

    1. To either an agar-containing diet or an agar-free diet, 0, 0.3 and 2.0 mg/100 g of beta-carotene were incorporated and fed to groups of five rats for 28 days. 2. Weight gain and food consumption of rats fed different dietary groups did not show a significant difference (P > 0.05). 3. Colon weight, colonic mucosal DNA and RNA were generally higher in rats fed agar diets than rats fed agar-free diets at either beta-carotene supplementation level. 4. Mucinase activity was higher (P < 0.05) in rats fed the agar diet than in rats fed an agar-free diet without beta-carotene. However, the difference was not observed (P > 0.05) when beta-carotene was incorporated. 5. These data suggest that colonic mucin degradation in rats fed an agar diet decreased when the dietary beta-carotene inclusion level increased. PMID:7687211

  19. Hypoxia/Reoxygenation Effects on Ion Transport across Rat Colonic Epithelium

    PubMed Central

    Schindele, Sabine; Pouokam, Ervice; Diener, Martin

    2016-01-01

    Ischemia causes severe damage in the gastrointestinal tract. Therefore, it is interesting to study how the barrier and transport functions of intestinal epithelium change under hypoxia and subsequent reoxygenation. For this purpose we simulated hypoxia and reoxygenation on mucosa-submucosa preparations from rat distal colon in Ussing chambers and on isolated crypts. Hypoxia (N2 gassing for 15 min) induced a triphasic change in short-circuit current (Isc): a transient decrease, an increase and finally a long-lasting fall below the initial baseline. During the subsequent reoxygenation phase, Isc slightly rose to values above the initial baseline. Tissue conductance (Gt) showed a biphasic increase during both the hypoxia and the reoxygenation phases. Omission of Cl− or preincubation of the tissue with transport inhibitors revealed that the observed changes in Isc represented changes in Cl− secretion. The radical scavenger trolox C reduced the Isc response during hypoxia, but failed to prevent the rise of Isc during reoxygenation. All changes in Isc were Ca2+-dependent. Fura-2 experiments at loaded isolated colonic crypts revealed a slow increase of the cytosolic Ca2+ concentration during hypoxia and the reoxygenation phase, mainly caused by an influx of extracellular Ca2+. Surprisingly, no changes could be detected in the fluorescence of the superoxide anion-sensitive dye mitosox or the thiol-sensitive dye thiol tracker, suggesting a relative high capacity of the colonic epithelium (with its low O2 partial pressure even under physiological conditions) to deal with enhanced radical production during hypoxia/reoxygenation. PMID:27445839

  20. Actions of hydrogen sulphide on ion transport across rat distal colon

    PubMed Central

    Hennig, B; Diener, M

    2009-01-01

    Background and purpose: The aim of this study was to identify the actions of H2S on ion transport across rat distal colon. Experimental approach: Changes in short-circuit current (Isc) induced by the H2S-donor, NaHS, were measured in Ussing chambers. Cytosolic Ca2+ concentration was evaluated using fura-2. Key results: NaHS concentration-dependently induced a change in Isc, that was only partially inhibited by the neurotoxin, tetrodotoxin. Lower concentrations (≤10−3 mol·L−1) of NaHS induced a monophasic increase in Isc, whereas higher concentrations induced an additional, secondary fall of Isc, before a third phase when Isc rose again. Blockers of H2S-producing enzymes (expression demonstrated immunohistochemically) decreased basal Isc, suggesting that endogenous production of H2S contributes to spontaneous anion secretion. The positive Isc phases induced by NaHS were due to Cl− secretion as shown by anion substitution and transport inhibitor experiments, whereas the transient negative Isc induced by higher concentrations of the H2S-donor was inhibited by mucosal tetrapentylammonium suggesting a transient K+ secretion. When applied from the serosal side, glibenclamide, an inhibitor of ATP-sensitive K+ channels, and tetrapentylammonium, a blocker of Ca2+-dependent K+ channels, suppressed NaHS-induced Cl− secretion suggesting different types of K+ channels are stimulated by the H2S-donor. NaHS-induced increase in cytosolic Ca2+ concentration was confirmed in isolated, fura-2-loaded colonic crypts. This response was not dependent on extracellular Ca2+, but was inhibited by blockers of intracellular Ca2+ channels present on Ca2+ storage organelles. Conclusions and implications: H2S induces colonic ion secretion by stimulation of apical as well as basolateral epithelial K+ channels. PMID:19785650

  1. Brewers’ rice modulates oxidative stress in azoxymethane-mediated colon carcinogenesis in rats

    PubMed Central

    Tan, Bee Ling; Norhaizan, Mohd Esa; Huynh, Ky; Yeap, Swee Keong; Hazilawati, Hamzah; Roselina, Karim

    2015-01-01

    AIM: To investigate the mechanistic action of brewers’ rice in regulating the Wnt/nuclear factor-kappa B (NF-κB)/Nrf2-signaling pathways during colon carcinogenesis in male Sprague-Dawley rats. METHODS: Male Sprague-Dawley rats were randomly divided into the following five groups (six rats in each group): (G1) normal, (G2) azoxymethane (AOM) alone, (G3) AOM + 10% (weight (w)/weight (w)) brewers’ rice, (G4) AOM + 20% (w/w) brewers’ rice, and (G5) AOM + 40% (w/w) brewers’ rice. They were intraperitoneally administered 15 mg/kg body weight of AOM in saline once weekly over a two-week period and treated with an American Institute of Nutrition (AIN)-93G diet containing 10%, 20%, and 40% (w/w) brewers’ rice. The mRNA levels of glycogen synthase kinase 3β (GSK3β), β-catenin, key inflammation markers, nuclear factor E2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1)-dependent transcriptional activity were assessed by quantitative real-time polymerase chain reaction analyses. The colon superoxide dismutase, malondialdehyde, and nitric oxide levels were also analyzed to assess the antioxidant effect of these treatments. The results were analyzed using one-way analysis of variance (ANOVA), and a P value of < 0.05 was considered significant. RESULTS: The overall analyses demonstrated that the dietary administration of brewers’ rice in AOM-induced rat colon carcinogenesis resulted in the transcriptional upregulation of GSK3β, inducible nitric oxide synthase (iNOS), Nrf2, and HO-1. We discovered that the dietary administration of brewers’ rice downregulated the β-catenin and NF-κB mRNA levels. A significant reduction in β-catenin expression was found in the groups administered with 20% (0.611 ± 0.034) and 40% (0.436 ± 0.045) (w/w) brewers’ rice compared with that of the group treated with AOM alone (1.000 ± 0.064) (P < 0.05). The NF-κB expression was significantly lower between the AOM-alone group (1.000 ± 0.048) and those groups fed with diets

  2. Chronic infection with Toxoplasma gondii induces death of submucosal enteric neurons and damage in the colonic mucosa of rats.

    PubMed

    Góis, Marcelo Biondaro; Hermes-Uliana, Catchia; Barreto Zago, Maísa Cristina; Zanoni, Jacqueline Nelisis; da Silva, Aristeu Vieira; de Miranda-Neto, Marcílio Hubner; Almeida Araújo, Eduardo José de; Sant'Ana, Débora de Mello Gonçales

    2016-05-01

    Intestinal epithelial secretion is coordinated by the submucosal plexus (SMP). Chemical mediators from SMP regulate the immunobiological response and direct actions against infectious agents. Toxoplasma gondii is a worldwide parasite that causes toxoplasmosis. This study aimed to determine the effects of chronic infection with T. gondii on the morphometry of the mucosa and the submucosal enteric neurons in the proximal colon of rats. Male adult rats were distributed into a control group (n = 10) and an infected group (n = 10). Infected rats received orally 500 oocysts of T. gondii (ME-49). After 36 days, the rats were euthanized and samples of the proximal colon were processed for histology to evaluate mucosal thickness in sections. Whole mounts were stained with methylene blue and subjected to immunohistochemistry to detect vasoactive intestinal polypeptide. The total number of submucosal neurons decreased by 16.20%. Vasoactive intestinal polypeptide-immunoreactive neurons increased by 26.95%. Intraepithelial lymphocytes increased by 62.86% and sulfomucin-producing goblet cells decreased by 22.87%. Crypt depth was greater by 43.02%. It was concluded that chronic infection with T. gondii induced death and hypertrophy in the remaining submucosal enteric neurons and damage to the colonic mucosa of rats. PMID:26902605

  3. Prophylactic administration of topical glutamine enhances the capability of the rat colon to resist inflammatory damage.

    PubMed

    Israeli, Eran; Berenshtein, Eduard; Wengrower, Dov; Aptekar, Larisa; Kohen, Ron; Zajicek, Gershom; Goldin, Eran

    2004-10-01

    Glutamine is an important nutrient for the GI tract and has been shown to exert a protective effect on the bowel. Nonetheless, in the context of IBD, data demonstrating a therapeutic role for glutamine has been inconclusive. IBD is associated with oxidative stress caused by reactive oxygen species. We aimed to investigate the effect of topical glutamine administration in rats before or after induction of colitis by trinitrobenzenosulfonic acid. In study I glutamine enemas were given beginning 2 days before or on the same day of induction of colitis. Inflammation severity was assessed by macroscopic and microscopic score and tissue myeloperoxidase activity. In study II glutamine enemas were given for 3 days without induction of colitis: mitotic index and colonic crypt length were measured, as well as water-soluble low molecular weight antioxidants and energy-rich phosphate levels (by HPLC). Results showed that glutamine significantly decreased indexes of inflammation when administered before induction of colitis. Glutamine caused an increase in the mitotic index and the levels of water-soluble low molecular weight antioxidants and energy-rich phosphates. We conclude that glutamine exerts a beneficial effect only when administered before induction of colitis, by increasing the resistance of the colonic tissue to inflammatory injury. This effect is probably mediated by increasing the antioxidant capacity and energy level of the tissue. PMID:15573931

  4. Analysis of colon tumors in rats by near-infrared Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Duarte, Janaína; Hage, Raduan; Silveira, Landulfo, Jr.; Silveira, Fabricio; Pacheco, Marcos Tadeu T.; Munin, Egberto; Plapler, Hélio

    2007-02-01

    Biomedical applications of near-infrared Raman spectroscopy have increased their importance at the last ten years. This technique can determinate the molecular composition of materials, allowing a sensible and fast biological diagnosis. It has showed to be a promising tool for health diagnosis due to its high sensibility. Colorectal cancer (CRC) is one of the most common malignant tumors in humans beings. In the last decades many experimental models have been developed in animals based in the use of chemical composites to induce the formation and development of these tumors, many of them present similar characteristics to those of natural occurrence aiming to the attainment of information on genesis, evolution, as well as diagnosis and more efficient therapies for treating these neoplasias. Amongst the most used chemical composites is the 1,2- dimetilhydrazine (DMH) because its morphological and histological similarity to those tumors. This study aims to compare in vivo normal colon tissue and tumoral colon tissue, induced by DMH, in rats by near-infrared Raman spectroscopy to permit the use in the near future for an efficient diagnosis in real time besides being useful as an auxiliary method for several therapies, including the photodynamic therapy.

  5. Structure-Activity Relationships of Somatostatin Analogs in the Rabbit Ileum and the Rat Colon

    PubMed Central

    Rosenthal, Linda E.; Yamashiro, Darrell J.; Rivier, Jean; Vale, Wylie; Brown, Marvin; Dharmsathaphorn, Kiertisin

    1983-01-01

    Somatostatin increases absorption of electrolytes and inhibits diarrhea in patients with endocrine tumors and short bowel syndrome. In an attempt to develop a gut-specific somatostatin analog, each amino acid in the somatostatin molecule was replaced with L-alanine, deleted, or substituted with its D-isomer. The potency of each analog to stimulate ion transport in the rabbit ileum was then determined using the modified Ussing chamber technique. The results were compared to the ability of each analog to inhibit the stimulated release of growth hormone from cultured rat anterior pituitary cells and to inhibit the arginine-stimulated release of insulin and glucagon in the rat in vivo. Analogs that showed gut selectivity were then tested for their ion transport properties in the rat colon. Results: (a) Substitution with L-alanine or deletion of the amino acid at position 6, 7, 8, or 9 and deletion of Threonine10-produced analogs with significantly reduced ion transport properties to <4% of somatostatin's action. The substitution also markedly reduced the ability of the compounds to inhibit the release of growth hormone, insulin, and glucagon. (b) Selectivity of intestinal ion transport was achieved by any one of the following alterations: L-alanine substitution at Phenylalanine11, deletion of Phenylalanine11, substitution with D-lysine at Lysine4, or substitution with L-alanine at Lysine4. These compounds had intestinal ion transport properties of 52, 34, 139, and 94%, respectively, while demonstrating little or no inhibition of growth hormone, insulin or glucagon release. Conclusions: (a) Phenylalanine6, Phenylalanine7, Tryptophan8, and Lysine9 are required for the ion transport and other biologic actions of somatostatin, whereas Threonine10 serves as an essential spacer. (b) Alteration at Phenylalanine11 or Lysine4 yields analogs that are selective for ion transport in the rabbit ileum and rat colon. These findings should be taken into consideration when developing a

  6. Lack of effect of dietary fat on N-nitrosomethyl urea (NMU)-induced colon tumorigenesis in rats.

    PubMed

    Nauss, K M; Locniskar, M; Sondergaard, D; Newberne, P M

    1984-02-01

    The effect of alterations in the quality and quantity of dietary fat on N-nitrosomethyl urea (NMU)-induced colon cancer in rats was studied. Weanling Sprague-Dawley rats were fed semipurified diets containing 24% beef fat, 24% corn oil, 24% Crisco or the three fats in equal parts to make a total of 5% fat. Macronutrients and micronutrients were adjusted to balance the nutrient to calorie ratios. After 4 weeks of dietary treatment, all rats, except vehicle-treated animals received NMU (1.5 mg) via intrarectal instillation, twice a week for 2 weeks. The animals continued receiving the experimental diets until intestinal tumors developed and surviving animals were sacrificed at 43 weeks. There was no effect of any of the high fat diets tested on intestinal tumor incidence, latency, distribution or size. Cumulative probability of death with colon carcinoma did not differ significantly among the dietary groups. PMID:6697442

  7. Effect of fermented oatmeal soup on the cholesterol level and the Lactobacillus colonization of rat intestinal mucosa.

    PubMed

    Molin, G; Andersson, R; Ahrné, S; Lönner, C; Marklinder, I; Johansson, M L; Jeppsson, B; Bengmark, S

    1992-04-01

    Rats were fed with freeze-dried oatmeal soup fermented by six different Lactobacillus strains from rat and man; the formula is intended for enteral feeding. The serum cholesterol levels after 10 d were lower for rats eating oatmeal as compared to a commercial product, Biosorb Sond. Colonizing ability of the administered strains were evaluated in vivo. Only Lactobacillus reuteri R21c were able to, effectively, colonizing the mucosa; it represented about 30% of the Lactobacillus population 24 d after termination of the administration. L. reuteri R21c was easily recognized by the ability to produce a yellow pigment on agar plates. The identity was confirmed by carbohydrate fermentations (API 50CH), plasmid pattern and endonuclease restriction analysis of the chromosomal DNA. PMID:1519914

  8. Moxibustion regulates inflammatory mediators and colonic mucosal barrier in ulcerative colitis rats

    PubMed Central

    Ma, Tie-Ming; Xu, Na; Ma, Xian-De; Bai, Zeng-Hua; Tao, Xing; Yan, Hong-Chi

    2016-01-01

    AIM: To observe the efficacy and mechanism of grain-sized moxibustion at different acupoints in a rat model of ulcerative colitis (UC). METHODS: Sprague-Dawley rats were randomly divided into control, UC model, grain-sized moxibustion at a single acupoint (CV 12), grain-sized moxibustion at two acupoints (CV 12 and CV 4), grain-sized moxibustion at three acupoints (CV 12, CV 4, and ST 36), and medication groups (n = 8/group). The UC model was established by enema of trinitrobenzene sulfonic acid. Direct moxibustion was used once a day for 7 d. Disease activity index (DAI) was evaluated before and after the treatment. Morphologic changes of intestinal tissue were observed under an optical microscope. The expression of tumor necrosis factor (TNF)-α and p38 mitogen-activated protein kinase (p38MAPK) in colonic tissue was detected using Western blot, and the levels of occludin and zonula occludens-1 (ZO-1) mRNAs were detected using reverse transcription PCR. RESULTS: Compared with the control group, the intestinal mucosae were incomplete in the model group, glandular structures were irregular, and submucosae were edematous, hyperemic, and infiltrated with inflammatory cells. The DAI scores and expression of TNF-α and p38MAPK were increased significantly in the model group compared to controls (Ps < 0.01), while the mRNA levels of occludin and ZO-1 were reduced significantly (Ps < 0.01). Compared with the model group, colonic mucosa and the arrangement of glands were complete and regular in the treatment groups. DAI scores and the expression of TNF-α and p38MAPK were reduced significantly in moxibustion groups compared to controls (Ps < 0.01), while the mRNA levels of occludin and ZO-1 were increased significantly (Ps < 0.01). The improvements in the above indices in the three acupoints group and the medication group were superior to those in the single and two acupoints groups (all P < 0.05). CONCLUSION: Reduction of TNF-α and p38MAPK and increased expression of

  9. Changes in Nitrergic and Tachykininergic Pathways in Rat Proximal Colon In Response to Chronic Treatment With Otilonium Bromide

    PubMed Central

    Cipriani, Gianluca; Gibbons, Simon J.; Arumugam, Saravanaperumal Siva; Malysz, John; Sha, Lei; Szurszewski, Joseph H.; Linden, David R.; Evangelista, Stefano; Faussone-Pellegrini, Maria Simonetta; Vannucchi, Maria Giuliana; Farrugia, Gianrico

    2015-01-01

    Background Otilonium bromide (OB) is used as a spasmolytic in the treatment of the functional bowel disorder irritable bowel syndrome. Although its acute effects on colonic relaxation are well-characterized, little is known about the effects of chronic administration of OB on enteric neurons, neuromuscular transmission, and interstitial cells of Cajal (ICC), key regulators of the gut function. Methods Adult Sprague-Dawley rats were treated with OB in drinking water at a dose of 2 mg/kg for 30 days. The colons of OB-treated and age-matched control rats were studied by confocal immunohistochemistry to detect immunoreactivity (IR) in myenteric plexus neurons for nitrergic and tachykininergic markers, and also by microelectrode electrophysiology. Results Using immunohistochemistry, chronic OB administration did not change total neuron number, assessed by anti-Hu IR, but resulted in a significant increase in NK1 receptor positive neurons, a decrease in neuronal nitric oxide synthase (nNOS) expressing neurons, and a reduction in volume of substance P in nerve fibers in the myenteric plexus. Chronic OB administration potentiated inhibitory and excitatory junction potentials evoked by repetitive electrical field stimulation. The various types of colonic ICC, detected by Kit IR, were not altered nor were slow waves or smooth muscle membrane potential. Conclusions and Inferences Chronic treatment with OB caused significant changes in the nitrergic and tachykinergic components of the myenteric plexus and in both inhibitory and excitatory neurotransmission in the rat colon. PMID:25930994

  10. Calcium inhibits promotion by hot dog of 1,2-dimethylhydrazine-induced mucin-depleted foci in rat colon.

    PubMed

    Santarelli, Raphaelle L; Naud, Nathalie; Taché, Sylviane; Guéraud, Françoise; Vendeuvre, Jean-Luc; Zhou, Lin; Anwar, Muhammad M; Mirvish, Sidney S; Corpet, Denis E; Pierre, Fabrice H F

    2013-12-01

    Epidemiology suggests that processed meat is associated with colorectal cancer risk, but few experimental studies support this association. We have shown that a model of cured meat made in a pilot workshop promotes preneoplastic lesions, mucin-depleted foci (MDF) in the colon of rats. This study had two aims: to check if real store-bought processed meats also promote MDF, and to test if calcium carbonate, which suppresses heme-induced promotion, can suppress promotion by processed meat. A 14-day study was done to test the effect of nine purchased cured meats on fecal and urinary biomarkers associated with heme-induced carcinogenesis promotion. Fecal water from rats given hot dog or fermented raw dry sausage was particularly cytotoxic. These two cured meats were thus given to rats pretreated with 1,2-dimethylhydrazine, to evaluate their effect on colorectal carcinogenesis. After a 100-days feeding period, fecal apparent total N-nitroso compounds (ATNC) were assayed and colons were scored for MDF. Hot dog diet increased fecal ATNC and the number of MDF per colon compared with the no-meat control diet (3.0 ± 1.7 vs. 1.2 ± 1.4, p < 0.05). In a third study, addition of calcium carbonate (150 µmol/g) to the hot dog diet decreased the number of MDF/colon and fecal ATNC compared with the hot dog diet without calcium carbonate (1.2 ± 1.1 vs. 2.3 ± 1.4, respectively, p < 0.05). This is the first experimental evidence that a widely consumed processed meat promotes colon carcinogenesis in rats. It also shows that dietary prevention of this detrimental effect is possible. PMID:23712585

  11. Oral supplementation with troxerutin (trihydroxyethylrutin), modulates lipid peroxidation and antioxidant status in 1,2-dimethylhydrazine-induced rat colon carcinogenesis.

    PubMed

    Vinothkumar, R; Vinoth Kumar, R; Karthikkumar, V; Viswanathan, P; Kabalimoorthy, J; Nalini, N

    2014-01-01

    The present study was aimed to investigate the chemopreventive potential of troxerutin on 1,2-dimethylhydrazine (DMH) induced rat colon carcinogenesis by evaluating the antioxidant and lipid peroxidation (LPO) status. Rats were randomly divided into six groups. Group I rats served as control. Group II rats received troxerutin (50 mg/kgb.w., p.o.) for 16 weeks. Groups III-VI rats received subcutaneous injections of DMH (20 mg/kgb.w., s.c.) once a week, for the first 4 weeks. In addition to DMH, groups IV-VI rats received troxerutin at the doses of 12.5, 25 and 50 mg/kgb.w., respectively. In DMH treated rats, our results showed decreased activities of antioxidants and increased levels of LPO in the liver. Moreover, LPO and antioxidants in the colon were found to be significantly diminished in DMH the treated rats. Furthermore, enhanced activity of colonic vitamin C and vitamin E levels were observed in DMH alone treated rats (group III), which was significantly reversed on troxerutin supplementation. Troxerutin at the dose of 25 mg/kgb.w. had shown profound beneficial effects by exhibiting near normal biochemical profile and well-preserved colon histology as compared to the other two tested doses (12.5 and 50 mg/kgb.w.). These findings suggest that troxerutin could serve as a novel agent for colon cancer chemoprevention. PMID:24355798

  12. Prolongation of Carrageenan-induced Inflammation in Human Colonic Epithelial Cells by Activation of an NFκB – BCL10 Loop

    PubMed Central

    Borthakur, Alip; Bhattacharyya, Sumit; Natarajan, Arivarasu A.; Kumar, Anoop; Dudeja, Pradeep K.; Tobacman, Joanne K.

    2013-01-01

    Carrageenan, a sulfated polysaccharide that is widely used as a food additive, induces inflammatory responses in animal models and human cells. The carrageenan-induced inflammatory cascades involve TLR4- and BCL10-dependent activation of NF-κB, leading to increased IL-8 production. Translocations involving BCL10 in the mucosa-associated lymphoid tissue (MALT) lymphomas are associated with constitutive activation of NF-κB. This report presents a mechanism by which carrageenan exposure leads to prolonged activation of both BCL10 and NF-κB in human colonic epithelial cells. Study findings demonstrate that nuclear RelA and RelB bind to an NF-κB binding motif in the BCL10 promoter in human colonic epithelial NCM460 and HT-29 cells. In vitro oligonucleotide binding assay, non-radioactive gel shift assay, and chromatin immunoprecipitation (ChIP) indicate binding of RelA and RelB to the BCL10 promoter. Prolonged inflammation follows activation of the BCL10-NFκB inflammatory loop in response to carrageenan, shown by increased BCL10, RelA, and IL-8 for 36 to 48 hours and increased RelB for 24 hours following withdrawal of carrageenan after 12 hours. In contrast, exposure to dextran sulfate sodium, which does not cause inflammation through TLR4 and BCL10 in the colonic epithelial cells, did not provoke prolonged activation of inflammation. The carrageenan-enhanced BCL10 promoter activity was blocked by caffeic acid phenethyl ester (CAPE) and MB-132 which inhibit NF-κB activation. These results indicate that NF-κB binding to the BCL10 promoter can lead to prolonged activation of the carrageenan-induced inflammatory cascade by a transcriptional mechanism involving an NF-κB – BCL10 loop. PMID:22579587

  13. Reduced susceptibility to azoxymethane-induced aberrant crypt foci formation and colon cancer in growth hormone deficient rats

    PubMed Central

    Carroll, Robert E.; Goodlad, Robert A.; Poole, Aleksandra J.; Tyner, Angela L.; Robey, R. Brooks; Swanson, Steven M.; Unterman, Terry G.

    2010-01-01

    Objectives To evaluate the role of GH in colon carcinogenesis, we examined the formation of aberrant crypt foci (ACFs) and tumor development in wild type (WT) and GH-deficient, spontaneous dwarf rats (SDRs) exposed to the carcinogen azoxymethane (AOM). Design ACF were quantified by stereomicroscopy and tumor number and weights were recorded for each animal. Cell proliferation was measured by vincristine metaphase arrest, flow cytometry, and bromode-oxyuridine (BrdU) incorporation. Apoptosis was measured by TUNEL staining and cleaved caspase-3 immunohistochemistry. IGF-I was measured by radioimmunoassay (RIA). Hexokinase activity was measured by spectrophotometric assay. PARP cleavage, and IGF-IR, and p27kip/cip expression were measured by Western blotting. Results ACFs detected by stereomicroscopy were markedly reduced (~85%) in SDRs vs. WT rats at 10, 25, and 28 weeks after AOM. Tumor incidence, number, and weight also were reduced in SDR vs. WT animals. AOM treatment increased cell proliferation in the distal colon (where tumors occur) of WT rats but not SDRs, and these changes corresponded to increased ACF and tumor formation. Apoptosis rates were similar in AOM-treated WT and SDRs. Alterations in serum IGF-I levels may contribute to differences in the proliferative response to AOM and decreased ACF formation in SDR vs. WT rats. Conclusions We conclude that early neoplastic lesions (ACFs) were reduced in GH-deficient animals. This effect corresponds with differences in AOM-induced proliferation, but not apoptosis. These data indicate that GH is required for the full effect of AOM on colon ACF and tumor development, and that the SDR rat is a promising model for studies regarding the role of GH/IGF system in the initiation and promotion of colon cancer. PMID:19406679

  14. Enhanced sympathetic nerve activity induced by neonatal colon inflammation induces gastric hypersensitivity and anxiety-like behavior in adult rats.

    PubMed

    Winston, John H; Sarna, Sushil K

    2016-07-01

    Gastric hypersensitivity (GHS) and anxiety are prevalent in functional dyspepsia patients; their underlying mechanisms remain unknown largely because of lack of availability of live visceral tissues from human subjects. Recently, we demonstrated in a preclinical model that rats subjected to neonatal colon inflammation show increased basal plasma norepinephrine (NE), which contributes to GHS through the upregulation of nerve growth factor (NGF) expression in the gastric fundus. We tested the hypothesis that neonatal colon inflammation increases anxiety-like behavior and sympathetic nervous system activity, which upregulates the expression of NGF to induce GHS in adult life. Chemical sympathectomy, but not adrenalectomy, suppressed the elevated NGF expression in the fundus muscularis externa and GHS. The measurement of heart rate variability showed a significant increase in the low frequency-to-high frequency ratio in GHS vs. the control rats. Stimulus-evoked release of NE from the fundus muscularis externa strips was significantly greater in GHS than in the control rats. Tyrosine hydroxylase expression was increased in the celiac ganglia of the GHS vs. the control rats. We found an increase in trait but not stress-induced anxiety-like behavior in GHS rats in an elevated plus maze. We concluded that neonatal programming triggered by colon inflammation upregulates tyrosine hydroxylase in the celiac ganglia, which upregulates the release of NE in the gastric fundus muscularis externa. The increase of NE release from the sympathetic nerve terminals concentration dependently upregulates NGF, which proportionately increases the visceromotor response to gastric distention. Neonatal programming concurrently increases anxiety-like behavior in GHS rats. PMID:27151940

  15. Peripheral corticotropin-releasing factor receptor type 2 activation increases colonic blood flow through nitric oxide pathway in rats

    PubMed Central

    Akiba, Yasutada; Kaunitz, Jonathan D.; Million, Mulugeta

    2015-01-01

    Background Corticotropin-releasing factor (CRF) peptides exert profound effects on the secretomotor function of the gastrointestinal tract. Nevertheless, despite the presence of CRF peptides and receptors in colonic tissue, their influence on colonic blood flow (CBF) is unknown. Aim To determine the effect and mechanism of members of the CRF peptide family on CBF in isoflurane-anesthetized rats. Methods Proximal CBF was measured with laser Doppler flowmetry simultaneously with mean arterial blood pressure (MABP) measurement. Rats were injected with intravenous human/rat CRF (CRF1>CRF2 affinity), mouse urocortin 2 (mUcn2, selective CRF2 agonist) or sauvagine (SVG, CRF2>CRF1 affinity) at 1 – 30 μg/kg. The nitric oxide (NO) synthase inhibitor, L-NAME (3 mg/kg, iv), the cyclooxygenase inhibitor, indomethacin (Indo, 5 mg/kg, ip) or selective CRF2 antagonist, astressin2-B (Ast2B, 50 μg/kg, iv) was given before SVG injection (10 μg/kg, iv). Results SVG and mUcn2 dose-dependently increased CBF while decreasing MABP and colonic vascular resistance (CVR). CRF had no effect on CBF, but increased CVR. The hyperemic effect of SVG was inhibited by L-NAME but not by Indo, whereas hypotension was partially reduced by L-NAME. Sensory denervation had no effect on SVG-induced changes. Ast2B inhibited SVG-induced hyperemia and decreased CVR, and partially reduced the hypotension. Conclusions Peripheral CRF2 activation induces colonic hyperemia through NO synthesis, without involving prostaglandin synthesis or sensory nerve activation, suggesting a direct action on the endothelium and myenteric neurons. Members of the CRF peptide family may protect the colonic mucosal via the activation of the CRF2 receptor. PMID:25701320

  16. Protein and lipid refeeding changes protein metabolism and colonic but not small intestinal morphology in protein-depleted rats.

    PubMed

    Qu, Z; Ling, P R; Tahan, S R; Sierra, P; Onderdonk, A B; Bistrian, B R

    1996-04-01

    In this study, we fed rats a 2% casein AIN 76 diet for 2 wk to produce protein malnutrition. We determined in these animals the effects of different concentrations of dietary protein refeeding (2% and 20% casein) on recovery and gut mucosal repletion and the potential role of type of dietary fat in the regulation of protein metabolism and mucosal growth by providing conventional long-chain triglyceride (LCT), a structured lipid composed of long-, medium- and short-chain fatty acids (SC/SL), or a physical mixture of the same components present in the structured lipid given as individual pure triglycerides (SC/PM) along with adequate amounts of protein and energy. The results confirmed that protein malnutrition can be reversed rapidly by protein refeeding, as indicated by an increase in body weight, positive nitrogen balance, liver growth and elevations in plasma concentrations of insulin-like growth factor-1, leucine and albumin. In the colon, crypt cell number, crypt depth and number of crypt cells in the rapidly proliferating fraction of the colon were greater in rats fed the higher protein diet. However, the general architecture of small intestinal mucosa, including duodenum, jejunum and ileum, was not affected by protein malnutrition. Although the number of colonic cells was similar with fat refeeding, there were significantly fewer displaying the proliferating cell nuclear antigen in the colonic epithelium when rats were fed SC/PM compared with SC/SL. Therefore, changes in colonic mucosal proliferation were only seen with repletion by adequate protein and by SC/SL feeding. PMID:8613894

  17. The role of cholinergic anti-inflammatory pathway in acetic acid-induced colonic inflammation in the rat.

    PubMed

    Kolgazi, Meltem; Uslu, Unal; Yuksel, Meral; Velioglu-Ogunc, Ayliz; Ercan, Feriha; Alican, Inci

    2013-09-01

    The "cholinergic anti-inflammatory pathway" provides neurological modulation of cytokine synthesis to limit the magnitude of the immune response. This study aimed to evaluate the impact of the cholinergic anti-inflammatory pathway on the extent of tissue integrity, oxidant-antioxidant status and neutrophil infiltration to the inflamed organ in a rat model of acetic acid-induced colitis. Colitis was induced by intrarectal administration of 5% acetic acid (1ml) to Sprague-Dawley rats (200-250g; n=7-8 per group). Control group received an equal volume of saline intrarectally. The rats were treated with either nicotine (1mg/kg/day) or huperzine A (0.1mg/kg/day) intraperitoneally for 3 days. After decapitation, the distal colon was scored macroscopically and microscopically. Tissue samples were used for the measurement of malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity. Formation of reactive oxygen species was monitored by using chemiluminescence (CL). Nuclear factor (NF)-κB expression was evaluated in colonic samples via immunohistochemical analysis. Trunk blood was collected for the assessment of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-10, resistin and visfatin levels. Both nicotine and huperzine A reduced the extent of colonic lesions, increased colonic MDA level, high MPO activity and NF-κB expression in the colitis group. Elevation of serum IL-1β level due to colitis was also attenuated by both treatments. Additionally, huperzine A was effective to reverse colitis-induced high lucigenin-enhanced CL values and serum TNF-α levels. Colitis group revealed decreased serum visfatin levels compared to control group which was completely reversed by nicotine. In conclusion, modulation of the cholinergic system either by nicotine or ACh esterase inhibition improved acetic acid-induced colonic inflammation as confirmed by macroscopic and microscopic examination and biochemical assays. PMID:23810507

  18. Role of the A2B receptor–adenosine deaminase complex in colonic dysmotility associated with bowel inflammation in rats

    PubMed Central

    Antonioli, L; Fornai, M; Awwad, O; Giustarini, G; Pellegrini, C; Tuccori, M; Caputi, V; Qesari, M; Castagliuolo, I; Brun, P; Giron, M C; Scarpignato, C; Blandizzi, C; Colucci, R

    2014-01-01

    BACKGROUND AND PURPOSE Adenosine A2B receptors regulate several physiological enteric functions. However, their role in the pathophysiology of intestinal dysmotility associated with inflammation has not been elucidated. Hence, we investigated the expression of A2B receptors in rat colon and their role in the control of cholinergic motility in the presence of bowel inflammation. EXPERIMENTAL APPROACH Colitis was induced by 2,4-dinitrobenzenesulfonic acid (DNBS). Colonic A2B receptor expression and localization were examined by RT-PCR and immunofluorescence. The interaction between A2B receptors and adenosine deaminase was assayed by immunoprecipitation. The role of A2B receptors in the control of colonic motility was examined in functional experiments on longitudinal muscle preparations (LMPs). KEY RESULTS A2B receptor mRNA was present in colon from both normal and DNBS-treated rats but levels were increased in the latter. A2B receptors were predominantly located in the neuromuscular layer, but, in the presence of colitis, were increased mainly in longitudinal muscle. Functionally, the A2B receptor antagonist MRS 1754 enhanced both electrically-evoked and carbachol-induced cholinergic contractions in normal LMPs, but was less effective in inflamed tissues. The A2B receptor agonist NECA decreased colonic cholinergic motility, with increased efficacy in inflamed LMP. Immunoprecipitation and functional tests revealed a link between A2B receptors and adenosine deaminase, which colocalize in the neuromuscular compartment. CONCLUSIONS AND IMPLICATIONS Under normal conditions, endogenous adenosine modulates colonic motility via A2B receptors located in the neuromuscular compartment. In the presence of colitis, this inhibitory control is impaired due to a link between A2B receptors and adenosine deaminase, which catabolizes adenosine, thus preventing A2B receptor activation. PMID:24286264

  19. Multiple mucin depleted foci, high proliferation and low apoptotic response in the onset of colon carcinogenesis of the PIRC rat, mutated in Apc.

    PubMed

    Femia, Angelo Pietro; Luceri, Cristina; Soares, Paulo Victoria; Lodovici, Maura; Caderni, Giovanna

    2015-03-15

    PIRC rats (F344/NTac-Apc (am1137) ) mutated in the Apc gene spontaneously develop colon tumors thus mimicking familial adenomatous polyposis (FAP) and sporadic colorectal cancer (CRC) more closely than Apc-based rodent models developing tumors mostly in the small intestine. To understand whether microscopic dysplastic lesions precede the development of macroscopic tumors, PIRC rat colon was examined for the presence of mucin depleted foci (MDF), microadenomas of the rodent and human colon. Few MDF (about 4/animal) were already present in 1-month-old rats and their number rapidly increases to about 250 in 8-month-old rats. These lesions showed Wnt signaling activation (nuclear β-catenin accumulation) and were dramatically decreased by sulindac (320 ppm), a drug with chemopreventive activity (MDF/rat at 4 months: 156 ± 8 and 38 ± 6 in controls and sulindac-treated rats, respectively, means ± SE, p < 0.001). Since altered proliferation and apoptosis could underlie the early phases of carcinogenesis, we studied these processes in the apparently normal colon mucosa (NM) of 1-month-old PIRC and wt rats. Colon proliferation (PCNA expression) was significantly higher in PIRC rats. Notably, PIRC rat NM showed resistance to apoptosis since it sustained proliferation and had lower apoptosis after a cytotoxic insult with 1,2 dimethylhydrazine. Gene expression of Myc, p21, Birc5, Ogg1, Apex1 and Sod2 were significantly up-regulated in the NM of PIRC rat. The overall results put forward PIRC rat as useful model of colon carcinogenesis, either to study the process itself or to test in vivo chemopreventive agents in both short- and long-term studies. PMID:25257656

  20. Mechanism Investigation of the Improvement of Chang Run Tong on the Colonic Remodeling in Streptozotocin-Induced Diabetic Rats

    PubMed Central

    Sha, Hong; Zhao, Dong; Tong, Xiaolin; Zhao, Jingbo

    2016-01-01

    Previous study demonstrated that Chang Run Tong (CRT) could partly restore the colon remodeling in streptozotocin- (STZ-) induced diabetic rats. Here we investigated the mechanisms of such effects of CRT. Diabetes was induced by a single injection of 40 mg/kg of STZ. CRT was poured into the stomach by gastric lavage once daily for 60 days. The remodeling parameters were obtained from diabetic (DM), CRT treated diabetic (T1, 50 g/kg; T2, 25 g/kg), and normal (Con) rats. Expressions of advanced glycation end product (AGE), AGE receptor, transforming growth factor-β1 (TGF-β1), and TGF-β1 receptor in the colon wall were immunochemically detected and quantitatively analyzed. The association between the expressions of those proteins and the remodeling parameters was analyzed. The expressions of those proteins were significantly higher in different colon layers in the DM group (P < 0.05, P < 0.01) and highly correlated to the remodeling parameters. Furthermore, the expressions of those proteins were significantly decreased in the T1 group (P < 0.05, P < 0.01) but not in the T2 group (P > 0.05). The corrective effect on the expressions of those proteins is likely to be one molecular pathway for the improvement of CRT on the diabetes-induced colon remodeling. PMID:26839890

  1. Effects of 1,25-dihydroxyvitamin D3 on colonic calcium transport in vitamin D-deficient and normal rats.

    PubMed

    Favus, M J; Langman, C B

    1984-03-01

    To determine whether prior vitamin D intake influences the intestinal calcium absorptive action of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], we measured in vitro the two unidirectional transepithelial fluxes of calcium across descending colon segments from rats fed either a vitamin D-deficient or normal diet and injected with either 10, 25, or 75 ng of 1,25(OH)2D3 or vehicle alone. Vitamin D deficiency abolished net calcium absorption [J net, -2 +/- 2 vs. 12 +/- 2 (SE) nmol X cm-2 X h-1, P less than 0.001], and 10 ng of 1,25(OH)2D3 raised J net to levels found in normal rats. Larger doses (25 and 75 ng) increased J net above levels in normal rats given the same dose. In normal rats only 75 ng of 1,25(OH)2D3 increased calcium J net above vehicle control values (12 +/- 2 vs. 38 +/- 4 nmol X cm-2 X h-1, P less than 0.001). Circulating 1,25(OH)2D3 measured by radioreceptor assay was well correlated with calcium transport. For each dose of 1,25(OH)2D3 higher serum 1,25(OH)2D3 levels were reached in vitamin D-deficient rats. Only the 75-ng dose increased circulating 1,25(OH)2D3 and colonic calcium transport in normal rats. Intravenous [3H]-1,25(OH)2D3 disappeared more rapidly from the circulation of normal rats, suggesting that accelerated metabolic degradative processes for 1,25(OH)2D3 may be present in normal but not in vitamin D-deficient rats and may account for the lack of a biological response to 1,25(OH)2D3 in normal animals. PMID:6546644

  2. Mucin secretion in germfree rats fed fiber-free and psyllium diets and bacterial mass and carbohydrate fermentation after colonization.

    PubMed

    Cabotaje, L M; Shinnick, F L; Lopéz-Guisa, J M; Marlett, J A

    1994-04-01

    The effect of psyllium on mucin secretion was determined by comparing water-soluble and -insoluble fractions of excreta from germfree rats fed a fiber-free (FF) diet or a diet containing psyllium seed husk (PS). Excreta from the same rats after colonization with a rat mixed cecal culture were separated into water-soluble, plant, and bacterial fractions to compare the remaining carbohydrate and the mass of bacteria. The sugar composition and water solubility of carbohydrate in excreta from germfree rats fed FF diets indicated that a primary fermentable substrate was mucin. PS increased fecal excretion of mucin-derived sugars almost threefold in germfree rats. Fecal carbohydrate was reduced from 619 to 237 mumol/g of dry feces and mostly in the bacterial fraction when rats fed an FF diet were colonized. The total sugar content and the amount of muramic acid, but not bacterial counts and mass, indicated that PS increased fecal bacteria. Fractionation of excreta from PS-fed rats was complicated by a gel which, based on sugar composition, was PS. Sugar composition of the water-soluble fraction from excreta from PS-fed rats suggested that it contained some bacterial component, possibly exopolysaccharides and some of the PS, but not mucin. PS digestibility ranged from 60 to 80%, depending on what fecal fraction was used for output. Because of the presence of PS-derived sugars in the gel and soluble fraction, it was not possible to determine which, if any, of the PS digestibilities was correct. PMID:8017918

  3. Exclusion of the RET proto-oncogene as candidate for total colonic aganglionsis in the spotting lethal (sl) rat strain

    SciTech Connect

    Ceccherini, I.; Matera, I.; Devoto, M.

    1994-09-01

    Causative germline mutations and deletions of the RET proto-oncogene have been demonstrated in a number of Hirschsprung disease (HSCR) patients showing either short- or long-segment intestinal aganglionosis, including both sporadic and familial cases with an autosomal dominant mode of inheritance. The spotting lethal (sl) rats show autosomal recessive recurrence of total colonic aganglionosis which resembles the long-segment HSCR type in humans with 100% mortality of the homozygotes at 4-5 weeks of age. Heterozygotes were backcrossed with DA rats and the F2 offspring was used to test the possible cosegregation of the aganglionosis and the RET proto-oncogene. A genomic DNA fragment of the rat RET gene was amplified using degenerated oligonucleotides, subcloned and sequenced. The coding portion of this DNA fragment (300bp) shares 93% and 81% of its amino acids with the murine and human RET proto-oncogene, respectively. An A{yields}G transition in the third nucleotide of the alanine codon corresponding to amino acid Glu90 of the human RET gene was identified in the sl but not in the wild type DA strain. This mutation creates a Bsp 1286I restriction site. Restriction analysis performed on 57 affected rats (mutated homozygotes) of the F2 generation revealed independent segregation between the rat colonic aganglionosis gene and RET, thus allowing the exclusion of the latter proto-oncogene as candidate for the mutation present in the sl rat strain. Several different candidate rat chromosomal regions are being analyzed in order to proceed with the mapping of the genetic defect in the sl rats.

  4. Distribution of lymphoid nodules, aberrant crypt foci and tumours in the colon of carcinogen-treated rats.

    PubMed Central

    Cameron, I. L.; Garza, J.; Hardman, W. E.

    1996-01-01

    Sprague-Dawley rats were given eight weekly subcutaneous injections of 1,2-dimethylhydrazine (DMH) or of vehicle then were sacrificed at 1, 5 or 24 weeks after the last injection of DMH. The locations of pre-existing aggregates of lymphoid nodules (ALNs), the location and multiplicity (size) of aberrant crypt foci (ACF), and the locations of tumours in the colon were determined. A trimodal distribution of pre-existing ALNs along the length of the colon was significantly correlated with the timodal distribution of DMH-induced adenocarcinomas (ACs). A unimodal peak in ACF of all sizes occurred between the sites of two distal ALNs. Thus, the distribution of ACF at 1 or 5 weeks did not correlate with distribution of AC found at 24 weeks. Of the 2640 ACF observed at 1 or at 5 weeks, none were found in the proximal 25% of the colon where ACs eventually occurred. It was concluded that: (1) ALNs play a promotional role in AC formation; (2) the ACs which form in the proximal quarter of the colon seldom if ever form via an ACF precursor; and (3) the location, the number and the size of ACF observed early after DMH exposure did not correlate with the location or predict the incidence of ACs which eventually formed in the colon. Images Figure 1 PMID:8611402

  5. Anticarcinogenic Effect of Corn Tortilla Against 1,2-Dimethylhydrazine (DMH)-Induced Colon Carcinogenesis in Sprague-Dawley Rats.

    PubMed

    Reynoso-Camacho, Rosalía; Guerrero-Villanueva, Guadalupe; Figueroa, Juan de Dios; Gallegos-Corona, Marco A; Mendoza, Sandra; Loarca-Piña, Guadalupe; Ramos-Gomez, Minerva

    2015-06-01

    Mexico has the highest per capita consumption of corn in the world, which is consumed mainly as tortilla. However, only a few in vivo studies have demonstrated the anticarcinogenic potential of some maize components against colon cancer, but not as a whole food product. Therefore, our objective was to evaluate the protective effect of corn tortillas against the development of colon cancer. First, blue, red, yellow and white corn grains were lime-cooked and processed to elaborate tortillas. Then, tortillas were administered into the diet (27% w/w) to male Sprague-Dawley rats induced with the colon carcinogen 1,2-dimethylhydrazine (DMH). Our results indicated that consumption of tortillas, particularly from white and blue corns, significantly decreased adenocarcinoma incidence (up to 77.5%) and mean number compared to DMH-treated animals. In addition, an inhibition of β-glucuronidase activity, and induction of detoxifying enzymes in liver and colon, as well as a decrease in the expression of the two most important proliferative proteins (K-ras and β-catenin) involved in colon carcinogenesis, were also observed. These results highlight some of the molecular mechanisms related to the chemopreventive effect of tortillas, thus indicating that corn products retain their biological properties even after nixtamalization and tortilla processing. PMID:25680741

  6. Chemopreventive effects of aloin against 1,2-dimethylhydrazine-induced preneoplastic lesions in the colon of Wistar rats.

    PubMed

    Hamiza, O O; Rehman, M U; Khan, R; Tahir, M; Khan, A Q; Lateef, A; Sultana, S

    2014-02-01

    Chemoprevention opens new window in the prevention of all types of cancers including colon cancer. Aloin, an anthracycline in plant pigment, can be utilized as a protective agent in cancer induction. In the present study, we have evaluated the chemopreventive efficacy of aloin against 1,2-dimethylhydrazine (DMH)-induced preneoplastic lesions in the colon of Wistar rats. DMH-induced aberrant crypt foci (ACF) and mucin-depleted foci (MDF) have been used as biomarkers of colon cancer. Efficacy of aloin against the colon toxicity was evaluated in terms of biochemical estimation of antioxidant enzyme activities, lipid peroxidation, ACF, MDF, histopathological changes, and expression levels of molecular markers of inflammation and tumor promotion. Aloin pretreatment ameliorates the damaging effects induced by DMH through a protective mechanism that involved reduction in increased oxidative stress enzymes (p < 0.001), ACF, MDF, cyclooxygenase-2, inducible nitric oxide synthase, interleukin-6, proliferating cell nuclear antigen protein expression, and tumor necrosis factor-α (p < 0.001) release. From the results, it could be concluded that aloin clearly protects against chemically induced colon toxicity and acts reasonably by inducing antioxidant level, anti-inflammatory and antiproliferative markers. PMID:23928829

  7. Long-term colonic hypersensitivity in adult rats induced by neonatal unpredictable vs predictable shock.

    PubMed

    Tyler, K; Moriceau, S; Sullivan, R M; Greenwood-van Meerveld, B

    2007-09-01

    Our goal was to examine the relationship between early life trauma and the development of visceral hypersensitivity in later life in irritable bowel syndrome (IBS). Rat pups underwent neonatal conditioning: (i) paired odour-shock, where odour is a predictable shock signal, (ii) unpaired odour-shock, where odour is an unpredictable shock signal or (iii) control odour-only with odour presentations and handling without shock. At maturity, colorectal sensitivity was measured as a visceromotor behavioural response. In adulthood, colorectal distension (CRD) induced a pressure-dependent increase in the number of abdominal muscle contractions all three experimental groups. However, compared to animals that had received control odour-only presentations in infancy, there was an attenuated response to CRD in animals previously exposed to neonatal predictable shock pups and an exaggerated response in the animals previously exposed to neonatal unpredictable shock. Adult responses to CRD were altered by infant experience with shock trauma. However, depending on the context of that early life trauma, there are major differences between the long-term effects of that early life trauma on colonic sensitivity compared to controls. These results strengthen the link between early life trauma and adult IBS, and suggest that unpredictable trauma is a critical factor for later life disorders. PMID:17727395

  8. Alteration of the rat cecal microbiome during colonization with the helminth Hymenolepis diminuta

    PubMed Central

    McKenney, Erin A; Williamson, Lauren; Yoder, Anne D; Rawls, John F; Bilbo, Staci D; Parker, William

    2015-01-01

    The microbiome is now widely recognized as being important in health and disease, and makes up a substantial subset of the biome within the ecosystem of the vertebrate body. At the same time, multicellular, eukaryotic organisms such as helminths are being recognized as an important component of the biome that shaped the evolution of our genes. The absence of these macroscopic organisms during the early development and life of humans in Western culture probably leads to a wide range of human immunological diseases. However, the interaction between the microbiome and macroscopic components of the biome remains poorly characterized. In this study, the microbiome of the cecum in rats colonized for 2 generations with the small intestinal helminth Hymenolepis diminuta was evaluated. The introduction of this benign helminth, which is of considerable therapeutic interest, led to several changes in the cecal microbiome. Most of the changes were within the Firmicutes phylum, involved about 20% of the total bacteria, and generally entailed a shift from Bacilli to Clostridia species in the presence of the helminth. The results point toward ecological relationships between various components of the biome, with the observed shifts in the microbiome suggesting potential mechanisms by which this helminth might exert therapeutic effects. PMID:25942385

  9. Alteration of the rat cecal microbiome during colonization with the helminth Hymenolepis diminuta.

    PubMed

    McKenney, Erin A; Williamson, Lauren; Yoder, Anne D; Rawls, John F; Bilbo, Staci D; Parker, William

    2015-01-01

    The microbiome is now widely recognized as being important in health and disease, and makes up a substantial subset of the biome within the ecosystem of the vertebrate body. At the same time, multicellular, eukaryotic organisms such as helminths are being recognized as an important component of the biome that shaped the evolution of our genes. The absence of these macroscopic organisms during the early development and life of humans in Western culture probably leads to a wide range of human immunological diseases. However, the interaction between the microbiome and macroscopic components of the biome remains poorly characterized. In this study, the microbiome of the cecum in rats colonized for 2 generations with the small intestinal helminth Hymenolepis diminuta was evaluated. The introduction of this benign helminth, which is of considerable therapeutic interest, led to several changes in the cecal microbiome. Most of the changes were within the Firmicutes phylum, involved about 20% of the total bacteria, and generally entailed a shift from Bacilli to Clostridia species in the presence of the helminth. The results point toward ecological relationships between various components of the biome, with the observed shifts in the microbiome suggesting potential mechanisms by which this helminth might exert therapeutic effects. PMID:25942385

  10. Failure of prolactin short loop feedback mechanism to operate in old as compared to young female rats.

    PubMed

    Sarkar, D K; Miki, N; Meites, J

    1983-10-01

    The short loop feedback effect of PRL was studied in young (4-5 months of age) and old (24-26 months of age) ovariectomized rats after a single iv injection of bovine PRL (bPRL, 500 micrograms/100 g BW) or BSA (500 micrograms/100 g BW). Blood samples were collected via intraatrial cannula every 20 min for assay of PRL. Plasma PRL levels in both young and old ovariectomized rats were pulsatile in nature, and showed approximately one PRL pulse per hour. The magnitude of the PRL peaks and concentrations of plasma PRL, but not the number of PRL peaks, were significantly greater in the old than in the young rats. The effect of bPRL on in situ PRL release was studied after verifying that bPRL does not cross-react with rat PRL RIA, but does significantly increase the release of [3H] dopamine from the median eminence in vitro. This latter effect was dose dependent. In young rats, a single injection of bPRL minimally reduced the concentration of plasma PRL between 100 min and 5 h, but by 22-25 h it decreased plasma PRL to approximately one third of preinjection levels. The magnitude of the PRL pulses, but not the pulse frequency was significantly reduced after administration of bPRL treatment to young rats. Treatment with BSA did not alter the concentration of plasma PRL or the magnitude and frequency of the PRL pulses in young rats. In old rats, plasma PRL concentrations and the frequency and magnitude of the PRL pulses were not significantly decreased after injection of either bPRL or BSA. Thus, the feedback inhibition of PRL on PRL release may not be operative in old rats. The loss of the short loop feedback inhibition of PRL is believed to be due to the reduction in hypothalamic dopaminergic activity previously reported by our and other laboratories in old rats. PMID:6617580

  11. Effect of Ozone Therapy (OT) on Healing of Colonic Anastomosis in a Rat Model of Peritonitis

    PubMed Central

    Erginel, Başak; Erginel, Turgay; Aksoy, Bilgin; Dokucu, Ali İhsan

    2014-01-01

    significantly more oedema and necrosis in the control group rats, and collagen deposition in the anastomotic tissue was significantly higher in the ozone-treated groups on postoperative day 7. Hydroxyproline levels were significantly higher in groups O0 and O24 compared to the peritonitis group (P). Conclusion: Ozone therapy has a beneficial effect on anastomotic healing of the colon in the presence of peritonitis. PMID:25337422

  12. Effect of royal jelly on experimental colitis induced by acetic acid and alteration of mast cell distribution in the colon of rats

    PubMed Central

    Karaca, T.; Bayiroglu, F.; Yoruk, M.; Kaya, M.S.; Uslu, S.; Comba, B.; Mis, L.

    2010-01-01

    This study investigated the effects of royal jelly (RJ) on acetic acid-induced colitis in rats. Twenty adult female Wistar albino rats were divided into four treatment groups of 5 animals each, including a control group (Group I); Group II was treated orally with RJ (150 mg kg−1 body weight); Group III had acetic acid-induced colitis; and Group IV had acetic acid-induced colitis treated orally with RJ (150 mg kg−1 body weight) for 4 weeks. Colitis was induced by intracolonic instillation of 4% acetic acid; the control group received physiological saline (10 mL kg−1). Colon samples were obtained under deep anaesthesia from animals in all groups. Tissues were fixed in 10% formalin neutral buffer solution for 24 h and embedded in paraffin. Six-micrometre-thick sections were stained with Mallory’s triple stain and toluidine blue in 1% aqueous solution at pH 1.0 for 5 min (for Mast Cells). RJ was shown to protect the colonic mucosa against the injurious effect of acetic acid. Colitis (colonic damage) was confirmed histomorphometrically as significant increases in the number of mast cells (MC) and colonic erosions in rats with acetic acid-induced colitis. The RJ treatment significantly decreased the number of MC and reduced the area of colonic erosion in the colon of RJ-treated rats compared with rats with untreated colitis. The results suggest that oral treatment with RJ could be used to treat colitis. PMID:21263740

  13. Carbohydrate Metabolism Is Essential for the Colonization of Streptococcus thermophilus in the Digestive Tract of Gnotobiotic Rats

    PubMed Central

    Thomas, Muriel; Wrzosek, Laura; Ben-Yahia, Leila; Noordine, Marie-Louise; Gitton, Christophe; Chevret, Didier; Langella, Philippe; Mayeur, Camille; Cherbuy, Claire; Rul, Françoise

    2011-01-01

    Streptococcus thermophilus is the archetype of lactose-adapted bacterium and so far, its sugar metabolism has been mainly investigated in vitro. The objective of this work was to study the impact of lactose and lactose permease on S. thermophilus physiology in the gastrointestinal tract (GIT) of gnotobiotic rats. We used rats mono-associated with LMD-9 strain and receiving 4.5% lactose. This model allowed the analysis of colonization curves of LMD-9, its metabolic profile, its production of lactate and its interaction with the colon epithelium. Lactose induced a rapid and high level of S. thermophilus in the GIT, where its activity led to 49 mM of intra-luminal L-lactate that was related to the induction of mono-carboxylic transporter mRNAs (SLC16A1 and SLC5A8) and p27Kip1 cell cycle arrest protein in epithelial cells. In the presence of a continuous lactose supply, S. thermophilus recruited proteins involved in glycolysis and induced the metabolism of alternative sugars as sucrose, galactose, and glycogen. Moreover, inactivation of the lactose transporter, LacS, delayed S. thermophilus colonization. Our results show i/that lactose constitutes a limiting factor for colonization of S. thermophilus, ii/that activation of enzymes involved in carbohydrate metabolism constitutes the metabolic signature of S. thermophilus in the GIT, iii/that the production of lactate settles the dialogue with colon epithelium. We propose a metabolic model of management of carbohydrate resources by S. thermophilus in the GIT. Our results are in accord with the rationale that nutritional allegation via consumption of yogurt alleviates the symptoms of lactose intolerance. PMID:22216112

  14. A miR-34a-Numb Feedforward Loop Triggered by Inflammation Regulates Asymmetric Stem Cell Division in Intestine and Colon Cancer.

    PubMed

    Bu, Pengcheng; Wang, Lihua; Chen, Kai-Yuan; Srinivasan, Tara; Murthy, Preetish Kadur Lakshminarasimha; Tung, Kuei-Ling; Varanko, Anastasia Kristine; Chen, Huanhuan Joyce; Ai, Yiwei; King, Sarah; Lipkin, Steven M; Shen, Xiling

    2016-02-01

    Emerging evidence suggests that microRNAs can initiate asymmetric division, but whether microRNA and protein cell fate determinants coordinate with each other remains unclear. Here, we show that miR-34a directly suppresses Numb in early-stage colon cancer stem cells (CCSCs), forming an incoherent feedforward loop (IFFL) targeting Notch to separate stem and non-stem cell fates robustly. Perturbation of the IFFL leads to a new intermediate cell population with plastic and ambiguous identity. Lgr5+ mouse intestinal/colon stem cells (ISCs) predominantly undergo symmetric division but turn on asymmetric division to curb the number of ISCs when proinflammatory response causes excessive proliferation. Deletion of miR-34a inhibits asymmetric division and exacerbates Lgr5+ ISC proliferation under such stress. Collectively, our data indicate that microRNA and protein cell fate determinants coordinate to enhance robustness of cell fate decision, and they provide a safeguard mechanism against stem cell proliferation induced by inflammation or oncogenic mutation. PMID:26849305

  15. Effect of beef fat on DMH-induced colon tumorigenesis: influence of rat strain and nutrient composition.

    PubMed

    Nauss, K M; Bueche, D; Newberne, P M

    1987-04-01

    The modulating effect of high levels of dietary fat on chemically induced colon tumorigenesis has been studied in animal models, with conflicting results. The present study was designed to examine the influence of rat strain, stage of tumor development and micronutrient composition of the diet on 1,2-dimethylhydrazine (DMH)-induced intestinal tumorigenesis. Two strains of rats [Sprague-Dawley (SD) and Fischer-344 (F-344)] were fed one of three experimental diets. The diets contained 5 or 20% dietary fat but differed in nutrient composition and nutrient-energy ratio. After receiving the experimental diets for 4 wk, animals were treated with DMH X 2HCl (10 mg/kg body wt) once a week for 20 wk and killed 10 wk after receiving the last dose of carcinogen. Long-term administration of DMH was more toxic to F-344 rats than to SD animals, and the toxicity was potentiated by reductions in the micronutrient composition of the diet. High levels of dietary fat (20%) resulted in a barely significantly higher incidence in colon tumor (but not frequency or size) in SD rats that received the diet promoting optimal growth than did low levels of dietary fat. No effect of 20% beef fat was seen in SD animals fed a diet that produced a slower growth rate or in F-344 animals. PMID:3585524

  16. Chemoprevention of N-methylnitrosourea-induced colon carcinogenesis by ursodeoxycholic acid-5-aminosalicylic acid conjugate in F344 rats.

    PubMed

    Narisawa, Tomio; Fukaura, Yoko; Takeba, Naomi; Nakai, Keiko

    2002-02-01

    Bile acids enhance colon carcinogenesis in animal models, whereas ursodeoxycholic acid (UDCA) suppresses it. Nonsteroid anti-inflammatory drugs prevent colon cancer development in animals and humans. The aim of the present study was to explore the inhibitory effect of UDCA conjugate with 5-aminosalicylic acid (5-ASA), UDCA-5-ASA conjugate (UDCA-5-ASA), against colon carcinogenesis in rats. One-hundred-and-twenty-nine 7-week-old F344 rats received an intrarectal instillation of 2 mg of N-methylnitrosourea 3 times a week for 3 weeks, and were fed a 0% (control), 0.11% or 0.02% UDCA-5-ASA-, 0.08% UDCA- or 0.03% 5-ASA-supplemented diet for the next 27 weeks. The test diets contained an equimolar amount of a test agent, 2.0 mmol/kg diet, except for the 0.02% UDCA-5-ASA diet. The tumor incidence and the mean number of tumors/rat at week 30 were significantly lower and smaller in the UDCA-5-ASA diet groups, 48% and 0.7 in both, and marginally lower in the UDCA and 5-ASA diet groups, 56% and 0.9, and 64% and 0.8, compared to the control group, 83% and 1.3. All the tumors were polypoid in shape, and most of them were differentiated adenocarcinomas restricted to the mucosa or submucosa. An analysis by HPLC for bile acids and 5-ASA in the feces and serum collected at week 30 showed that one-half of ingested UDCA-5-ASA was cleaved into UDCA and 5-ASA in the colon. Thus, the two moieties may have independently affected the promotion stage of carcinogenesis. PMID:11856477

  17. Only weak vasorelaxant properties of loop diuretics in isolated resistance arteries from man, rat and guinea pig.

    PubMed

    Pickkers, Peter; Russel, Frans G M; Thien, Theo; Hughes, Alun D; Smits, Paul

    2003-04-18

    Besides their diuretic action, loop diuretics may induce a rapid vasodilator effect that contribute to their short-term therapeutic properties. We examined the effects of furosemide (10(-6)-10(-3) mol l(-1)) in comparison with bumetanide (10(-6)-10(-4) mol l(-1)) on isolated resistance arteries from rat and guinea pig mesentery and human subcutaneous fat, and investigated the mechanism of the acute direct vasorelaxant action on an isometric microvascular myograph. Both loop diuretics induced concentration-dependent relaxation of resistance vessels irrespective of membrane potential. The maximal effect of furosemide was greatest in rat and least in human arteries. Both diuretics caused a rightward shift in the concentration-response curve to extracellular Ca(2+). Incubation with indomethacin (2 x 10(-5) mol l(-1)) or mechanical removal of the endothelium did not inhibit the loop diuretic-induced relaxation. At high concentrations (10(-4)-10(-3) mol l(-1)) loop diuretics exert only weak direct relaxant effects on isolated human subcutaneous resistance arteries compared to the vasorelaxant effects in rat and guinea pig mesenteric vessels. PMID:12694811

  18. An enhanced cAMP pathway is responsible for the colonic hyper-secretory response to 5-HT in acute stress rats.

    PubMed

    Li, Y; Li, L S; Zhang, X L; Zhang, Y; Xu, J D; Zhu, J X

    2015-01-01

    5-hydroxytryptamine (5-HT) is involved in the stress-induced alteration of colonic functions, specifically motility and secretion, but its precise mechanisms of regulation remain unclear. In the present study, we have investigated the effects of 5-HT on rat colonic mucosal secretion after acute water immersion restraint stress, as well as the underlying mechanism of this phenomenon, using short circuit current recording (I(SC)), real-time polymerase chain reaction, Western blot analysis, and enzyme-linked immunosorbance assays. After 2 h of water immersion restraint stress, the baseline I(SC) and 5-HT-induced I(SC) responses of the colonic mucosa were significantly increased. Pretreatment with selective 5-HT(4) receptor antagonist, SB204070, inhibited the 5-HT-induced colonic I(SC) response by 96 % in normal rats and 91.2 % in acute-stress rats. However, pretreatment with the selective antagonist of 5-HT(3) receptor, MDL72222 or Y-25130, had no obvious effect on 5-HT-induced I(SC) responses under either set of conditions. Total protein expression of both the mucosal 5-HT(3) receptors and the 5-HT(4) receptors underwent no significant changes following acute stress. Both colonic basal cAMP levels and foskolin-induced I(SC) responses were significantly enhanced in acute stress rats. 5-HT significantly enhanced the intracellular cAMP level via 5-HT(4) receptors in the colonic mucosa from both control and stressed animals, and 5-HT-induced cAMP increase in stressed rats was not more than that in control rats. Taken together, the present results indicate that acute water immersion restraint stress enhances colonic secretory responses to 5-HT in rats, a process in which increased cellular cAMP accumulation is involved. PMID:25536313

  19. RNase mitochondrial RNA processing cleaves RNA from the rat mitochondrial displacement loop at the origin of heavy-strand DNA replication.

    PubMed

    Tullo, A; Rossmanith, W; Imre, E M; Sbisà, E; Saccone, C; Karwan, R M

    1995-02-01

    Ribonuclease mitochondrial RNA processing cleaves RNAs from the mammalian mitochondrial main non-coding regulatory region, called the displacement loop. Our data demonstrate that rat cells contain a site-specific ribonuclease mitochondrial RNA processing activity. We found that this enzyme processes the rat mitochondrial displacement-loop RNA substrate at the level of the conserved sequence block 1, a result which is different from that for mouse. This finding correlates with the in-vivo transcriptional analysis of the rat displacement-loop region. Processing by homologous and heterologous ribonuclease mitochondrial RNA enzymes occurs in the same manner, suggesting a conserved mode of substrate recognition. PMID:7532584

  20. Lactic acid fermentation of germinated barley fiber and proliferative function of colonic epithelial cells in loperamide-induced rats.

    PubMed

    Jeon, Jeong Ryae; Choi, Joon Hyuk

    2010-08-01

    To develop a functional food from the dietary fiber fraction of germinated barley (Hordeum vulgare L.) (GBF), lactic acid fermentation was attempted using Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium bifidus. The quality characteristics of the lactic acid-fermented product and its effect on gastrointestinal function in an animal model were examined. The anaerobic fermentation of 1% and 2% GBF yielded lactic acid bacteria at 8.9 +/- 1.0 x 10(8) and 1.6 +/- 0.2 x 10(9) colony-forming units/mL, and it was considered acceptable for consumption by sensory assessment. To determine the effect on gastrointestinal function, Sprague-Dawley rats were fed with three types of diets: a normal chow diet and chow diets supplemented with 10% lactic acid bacteria or a yogurt fermented with 2% GBF (GBFY). The rats fed GBFY for 6 weeks gained less body weight, excreted more fecal mass, and had improved gastrointestinal transit as examined with barium sulfate. The effect of GBFY on colonic epithelial proliferation was investigated through loperamide (LPM)-induced constipation in rats. The rats fed with GBFY for 6 weeks were intraperitoneally administered LPM twice daily for 7 days. GBFY supplementation decreased fecal excretion and moisture content in feces and depleted goblet cells as observed by hematoxylin and eosin stain. However, the rats supplemented with GBFY prior to the LPM administration had enhanced bowel movement, mucin secretion, and production of short-chain fatty acids compared with values for the LPM-alone group. Immunohistochemistry revealed that the GBFY supplement increased the numbers of nuclei stained positively for Ki-67 and extended from the base to the middle zone of crypts. These results indicate that GBFY alleviates constipation via the proliferation of the colonic crypts in LPM-administered rats. PMID:20673062

  1. Effect of colon tumor development and dietary fat on the immune system of rats treated with DMH.

    PubMed

    Locniskar, M; Nauss, K M; Newberne, P M

    1986-01-01

    We examined the effect of dietary fat and colon tumorigenesis on the morphology and function of the rat mesenteric lymph node (MLN) and spleen at two stages of tumor development. Male Sprague-Dawley rats were fed semipurified diets of varying fat content (5% mixed fat, 24% beef fat, 24% corn oil, or 24% Crisco) and treated for five weeks with either the colon carcinogen 1,2-dimethylhydrazine (DMH) or the vehicle (saline). Animals consuming high-fat diets had an increased incidence of splenic follicular and germinal center hyperplasia. Carcinogen treatment had no significant effect on the histological morphology of the spleen. MLN morphology was not dramatically affected by either diet or DMH treatment. At this time period, the splenic lymphocyte transformation response induced by concanavalin A (Con A), phytohemagglutinin, or pokeweed mitogen was significantly depressed in the group fed 24% corn oil (vehicle-treated) and in the DMH-treated groups fed 5% fat compared with the vehicle-treated group fed 5% fat. In contrast, the MLN transformation response was elevated in the group fed 24% Crisco. DMH treatment did not significantly influence the MLN response. Four months after carcinogen or vehicle treatment, at the point of colon tumor development, no statistically significant differences were seen in the splenic or MLN blastogenic responses of DMH- or saline-treated animals. Splenic natural killer cell cytotoxic activity was also not significantly affected by dietary fat, carcinogen treatment, or tumor development. PMID:3703686

  2. Evaluation of Chemopreventive Effects of Acanthus ilicifolius against Azoxymethane-Induced Aberrant Crypt Foci in the Rat Colon

    PubMed Central

    Almagrami, Amel A.; Alshawsh, Mohammed A.; Saif-Ali, Riyadh; Shwter, Abdrabuh; Salem, Sameer D.; Abdulla, Mahmood A.

    2014-01-01

    Background Acanthus ilicifolius, a mangrove medicinal plant, is traditionally used to treat a variety of diseases. The aim of this research is to assess the chemoprotective outcomes of A. ilicifolius ethanolic extract against azoxymethane (AOM) induced colonic aberrant crypt foci (ACF) in rats. Methodology/Principal Findings In our study, rats were arranged in to five groups. Rats in the normal control group were given subcutaneous injections of normal saline once weekly for 2 weeks. The AOM control, reference and treatment groups were given subcutaneous injection of AOM, 15 mg/kg body weight, once weekly for 2 weeks each. The reference group was treated with 35 mg/kg 5-Fluorouracil via intraperitoneal injection once weekly for 8 weeks, and the treatment groups were administered by gavage with 250 and 500 mg/kg A. ilicifolius extract daily for 8 weeks. Both normal and AOM control groups received the vehicle; 10% Tween-20 only. Rats treated with 250 mg/kg and 500 mg/kg of A. ilicifolius extracts showed a decrease in the mean number of ACF by 65% and 53%, respectively. Those fed with A. ilicifolius showed significantly decreased multiplicity of ACF formations when compared with the results from the AOM control group. The 250 mg/kg A. ilicifolius treatment group showed significant decreases in lipid peroxidation MDA levels when compared with the AOM control group. In immunohistochemistry staining, the proliferating nuclear cell antigen (PCNA)-positive cells were significantly higher in the AOM control group than in the A. ilicifolius-treated groups. RT-PCR showed that A. ilicifolius caused a change in the regulation of apoptosis-related genes expression. Conclusion/Significance The results of the current study show that AOM-treated rats receiving oral exposure to A. ilicifolius demonstrated a significant decrease in the number of ACF in the colon when compared to AOM-treated rats receiving vehicle only. A ilicifolius may be an effective herbal approach for the

  3. Differential Induction of Colitis and Gastritis in HLA-B27 Transgenic Rats Selectively Colonized with Bacteroides vulgatus or Escherichia coli

    PubMed Central

    Rath, Heiko C.; Wilson, Kenneth H.; Sartor, R. Balfour

    1999-01-01

    Resident bacteria play an important role in initiating and perpetuating gastrointestinal inflammation. We previously demonstrated that six commensal bacteria including Bacteroides vulgatus caused more aggressive colitis and gastritis in HLA-B27 transgenic rats than did the other five bacteria without B. vulgatus. This study compared the degree of gastrointestinal inflammation in gnotobiotic HLA-B27 transgenic rats monoassociated with either B. vulgatus or Escherichia coli. Gnotobiotic transgenic rats raised in Trexler isolators were selectively colonized with either B. vulgatus or E. coli. Control rats were either germfree or colonized with six common commensal bacteria (Streptococcus faecium, E. coli, Streptococcus avium, Eubacterium contortum, Peptostreptococcus productus, and B. vulgatus [DESEP-B]). After 1 month, all the rats were killed and tissues were prepared for histologic and biochemical evaluation. Colitis induced by B. vulgatus monoassociation was almost equal to that in DESEP-B-colonized rats and was significantly more severe than E. coli-induced colitis, which was absent by histological testing and mild by colonic myeloperoxidase and interleukin-1β concentration determinations. However, gastritis was detectable only in DESEP-B-associated rats. These studies suggest that not all resident bacteria have equal proinflammatory capabilities, since B. vulgatus alone is more active than E. coli alone in inducing colitis, and that colitis and gastritis result from different luminal bacterial stimuli. PMID:10338507

  4. Dietary fiber down-regulates colonic tumor necrosis factor alpha and nitric oxide production in trinitrobenzenesulfonic acid-induced colitic rats.

    PubMed

    Rodríguez-Cabezas, Maria Elena; Gálvez, Julio; Lorente, Maria Dolores; Concha, Angel; Camuesco, Desirée; Azzouz, Shamira; Osuna, Antonio; Redondo, Luis; Zarzuelo, Antonio

    2002-11-01

    Previous studies have revealed the beneficial effects exerted by dietary fiber in human inflammatory bowel disease, which were associated with an increased production of SCFA in distal colon. The aim of the present study was to elucidate the probable mechanisms involved in the beneficial effects of a fiber-supplemented diet (5% Plantago ovata seeds) in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis, with special attention to its effects on the production of some of the mediators involved in the inflammatory response, such as tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the fiber-supplemented diet for 2 wk before TNBS colitis induction and thereafter until colonic evaluation 1 wk later. The results obtained showed that dietary fiber supplementation facilitated recovery from intestinal insult as evidenced both histologically, by a preservation of intestinal cytoarchitecture, and biochemically, by a significant reduction in colonic myeloperoxidase activity and by restoration of colonic glutathione levels. This intestinal anti-inflammatory effect was associated with lower TNFalpha levels and lower NO synthase activity in the inflamed colon, showing significant differences when compared with nontreated colitic rats. Moreover, the intestinal contents from fiber-treated colitic rats showed a significantly higher production of SCFA, mainly butyrate and propionate. We conclude that the increased production of these SCFA may contribute to recovery of damaged colonic mucosa because they constitute substrates for the colonocyte and, additionally, that they can inhibit the production of proinflammatory mediators, such as TNFalpha and NO. PMID:12421838

  5. Oral Feeding of Probiotic Bifidobacterium infantis: Colonic Morphological Changes in Rat Model of TNBS-Induced Colitis.

    PubMed

    Javed, Najma H; Alsahly, Musaad B; Khubchandani, Jagdish

    2016-01-01

    Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology. It has been proposed that modifying the bacterial flora in intestine with probiotics may decrease the inflammatory process and prevent relapses in UC. We investigated the possible protective and therapeutic effects of a single strand of probiotic, Bifidobacterium infantis (BI), on colonic inflammation, in rats with regular feedings. Two groups of Lewis rats were prepared (n = 8). The first group was the control, sham-fed group (n = 4). The other group was the experimental BI-fed group (n = 4). Colitis was induced in both groups by intrarectal administration of TNBS under light anesthesia. The sham-fed colitis induced groups received a daily oral gavage feeding of 1.0 mL distilled water, whereas the B. infantis-fed group received 0.205 g of B. infantis dissolved in 1.0 mL distilled water daily. The change in body weight and food and water intake was recorded over the course of each study and analyzed. The rats were euthanized and tissues from the descending colon were harvested and analyzed microscopically and histologically. Results of our study indicated significant reduction in inflammation, mucosal damage, and preservation of goblet cells, as compared to the control animals. Modulation of gastrointestinal (GI) flora suggests a promising field in developing strategies for prevention and treatment of inflammatory bowel diseases by dietary modifications. PMID:27127686

  6. Oral Feeding of Probiotic Bifidobacterium infantis: Colonic Morphological Changes in Rat Model of TNBS-Induced Colitis

    PubMed Central

    Javed, Najma H.; Alsahly, Musaad B.; Khubchandani, Jagdish

    2016-01-01

    Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology. It has been proposed that modifying the bacterial flora in intestine with probiotics may decrease the inflammatory process and prevent relapses in UC. We investigated the possible protective and therapeutic effects of a single strand of probiotic, Bifidobacterium infantis (BI), on colonic inflammation, in rats with regular feedings. Two groups of Lewis rats were prepared (n = 8). The first group was the control, sham-fed group (n = 4). The other group was the experimental BI-fed group (n = 4). Colitis was induced in both groups by intrarectal administration of TNBS under light anesthesia. The sham-fed colitis induced groups received a daily oral gavage feeding of 1.0 mL distilled water, whereas the B. infantis-fed group received 0.205 g of B. infantis dissolved in 1.0 mL distilled water daily. The change in body weight and food and water intake was recorded over the course of each study and analyzed. The rats were euthanized and tissues from the descending colon were harvested and analyzed microscopically and histologically. Results of our study indicated significant reduction in inflammation, mucosal damage, and preservation of goblet cells, as compared to the control animals. Modulation of gastrointestinal (GI) flora suggests a promising field in developing strategies for prevention and treatment of inflammatory bowel diseases by dietary modifications. PMID:27127686

  7. N-acetylcysteine prevents deleterious effects of ischemia/reperfusion injury on healing of colonic anastomosis in rats.

    PubMed

    Kabali, B; Girgin, S; Gedik, E; Ozturk, H; Kale, E; Buyukbayram, H

    2009-01-01

    This study was designed to determine the effects of intraperitoneally or orally administered N-acetylcysteine (NAC) on wound healing following resection and anastomosis of a colon segment with ischemia/reperfusion injury. Forty female Sprague-Dawley rats were randomly allocated to one of four groups containing 10 rats each: (1) normal resection plus anastomosis; (2) ischemia/reperfusion plus resection plus anastomosis; (3) ischemia/reperfusion plus resection plus anastomosis plus intraperitoneal NAC; (4) ischemia/reperfusion plus resection plus anastomosis plus oral NAC. Group comparison showed that the anastomosis bursting pressure was significantly higher in group 3 than in the other groups. The mean tissue hydroxyproline concentration in the anastomotic tissue was significantly lower in group 2 than in the other groups. The collagen deposition was significantly increased on day 7 in groups 3 and 4 compared to the other groups. In conclusion, this study demonstrates that NAC significantly prevents the effects of reperfusion injury on colonic anastomoses in a rat model. PMID:19346747

  8. Soluble Fiber Dextrin and Soluble Corn Fiber Supplementation Modify Indices of Health in Cecum and Colon of Sprague-Dawley Rats

    PubMed Central

    Knapp, Brenda K.; Bauer, Laura L.; Swanson, Kelly S.; Tappenden, Kelly A.; Fahey, George C.; de Godoy, Maria R. C.

    2013-01-01

    The objective of this study was to evaluate health outcomes resulting from dietary supplementation of novel, low-digestible carbohydrates in the cecum and colon of Sprague-Dawley rats randomly assigned to one of four treatment groups for 21 days: 5% cellulose (Control), Pectin, soluble fiber dextrin (SFD), or soluble corn fiber (SCF). Rats fed Pectin had a higher average daily food intake, but no differences in final body weights or rates of weight gain among treatments were observed. No differences were observed in total short-chain fatty acid (SCFA) or branched-chain fatty acid (BCFA) concentrations in the cecum and colon of rats fed either SFD or SCF. The SFD and SCF treatments increased cecal propionate and decreased butyrate concentrations compared to Control or Pectin. Pectin resulted in increased BCFA in the cecum and colon. Supplementation of SFD and SCF had no effect on cecal microbial populations compared to Control. Consumption of SFD and SCF increased total and empty cecal weight but not colon weight. Gut histomorphology was positively affected by SFD and SCF. Increased crypt depth, goblet cell numbers, and acidic mucin were observed in both the cecum and colon of rats supplemented with SFD, SCF, and Pectin. These novel, low-digestible carbohydrates appear to be beneficial in modulating indices of hindgut morphology when supplemented in the diet of the rat. PMID:23381099

  9. Impaired barrier function by dietary fructo-oligosaccharides (FOS) in rats is accompanied by increased colonic mitochondrial gene expression

    PubMed Central

    Rodenburg, Wendy; Keijer, Jaap; Kramer, Evelien; Vink, Carolien; van der Meer, Roelof; Bovee-Oudenhoven, Ingeborg MJ

    2008-01-01

    Background Dietary non-digestible carbohydrates stimulate the gut microflora and are therefore presumed to improve host resistance to intestinal infections. However, several strictly controlled rat infection studies showed that non-digestible fructo-oligosaccharides (FOS) increase, rather than decrease, translocation of Salmonella towards extra-intestinal sites. In addition, it was shown that FOS increases intestinal permeability already before infection. The mechanism responsible for this adverse effect of FOS is unclear. Possible explanations are altered mucosal integrity due to changes in tight junctions or changes in expression of defense molecules such as antimicrobials and mucins. To examine the mechanisms underlying weakening of the intestinal barrier by FOS, a controlled dietary intervention study was performed. Two groups of 12 rats were adapted to a diet with or without FOS. mRNA was collected from colonic mucosa and changes in gene expression were assessed for each individual rat using Agilent rat whole genome microarrays. Results Among the 997 FOS induced genes we observed less mucosal integrity related genes than expected with the clear permeability changes. FOS did not induce changes in tight junction genes and only 8 genes related to mucosal defense were induced by FOS. These small effects are unlikely the cause for the clear increase in intestinal permeability that is observed. FOS significantly increased expression of 177 mitochondria-related genes. More specifically, induced expression of genes involved in all five OXPHOS complexes and the TCA cycle was observed. These results indicate that dietary FOS influences intestinal mucosal energy metabolism. Furthermore, increased expression of 113 genes related to protein turnover, including proteasome genes, ribosomal genes and protein maturation related genes, was seen. FOS upregulated expression of the peptide hormone proglucagon gene, in agreement with previous studies, as well as three other peptide

  10. In vivo fibre optic confocal imaging of microvasculature and nerves in the rat vas deferens and colon

    PubMed Central

    PAPWORTH, G. D.; DELANEY, P. M.; BUSSAU, L. J.; VO, L. T.; KING, R. G.

    1998-01-01

    A fluorescence confocal microscopy technique was employed to obtain subsurface images of nerve and microvascular structure in the vas deferens and colon of the living rat. The use of dual labelling with vital dyes and 2-channel confocal acquisition allowed differentiation of microscopic structure at both low and higher magnification. Characteristic staining patterns of nerves and blood vessels were repeatedly obtained in each tissue, suggesting the potential of this technique for studying morphological changes associated with surgical procedures and/or models of neuronal or vascular pathology. PMID:9723976

  11. Evaluation of intestinal absorption enhancement and local mucosal toxicity of two promoters. I. Studies in isolated rat and human colonic mucosae.

    PubMed

    Maher, Sam; Kennelly, Rory; Bzik, Victoria A; Baird, Alan W; Wang, Xuexuan; Winter, Desmond; Brayden, David J

    2009-11-01

    The effects of two absorption promoters, (sodium caprate (C(10)) and melittin), on intestinal permeability and viability were measured in intact rat and human colonic epithelia mounted in Ussing chambers. Apical-side addition of C(10) (10 mM) and melittin (10-50 microM) rapidly reduced the transepithelial electrical resistance (TEER) and increased the apparent permeability coefficient (Papp) of [(14)C]-mannitol and FITC-dextran-4 kDa (FD4) across colonic mucosae from both species. Effects of C(10) on flux were greater than those of melittin at the concentrations selected. C(10) irreversibly decreased TEER, but the effects of melittin were partially reversible. Enhanced permeability of polar sugars (0.18-70 kDa) in colonic mucosae with C(10) was accompanied by significant release of lactate dehydrogenase (LDH) from the luminal surface as well as by inhibition of electrogenic chloride secretion induced by the muscarinic agonist, carbachol (0.1-10 microM). Although melittin did not alter electrogenic chloride secretion in rat or human colonic mucosae, it caused leakage of LDH from rat tissue. Gross histology and electron microscopy of rat and human colonic mucosae demonstrated that each permeation enhancer can induce colonic epithelial damage at concentrations required to increase marker fluxes. C(10) led to more significant mucosal damage than melittin, characterised by sloughing and mucosal erosion. Overall, these results indicate that while C(10) and melittin increase transport of paracellular flux markers across isolated human and rat colonic mucosae in vitro, these effects are associated with some cytotoxicity. PMID:19737613

  12. Morphology and distribution of 1,2-dimethylhydrazine dihydrochloride-induced colon tumors and their relationship to gut-associated lymphoid tissue in the rat.

    PubMed

    Nauss, K M; Locniskar, M; Pavlina, T; Newberne, P M

    1984-10-01

    The histopathology and relationship of sym-dimethylhydrazine dihydrochloride [(DMH) CAS: 306-37-6; 1,2-dimethylhydrazine dihydrochloride]-induced colon tumors to colonic lymphoid aggregates were examined in outbred male Sprague-Dawley rats treated with saline or DMH and sacrificed at three intervals after treatment. The ratio of polypoid:sessile tumors was 71:29 four months after DMH treatment and 62:38 when tumors were fully developed. Colonic lymphoid aggregates were found 3-5 cm from the cecal-colonic junction, near the flexure of the ascending and transverse colon, and 3-5 cm from the rectum. There were no significant differences between saline-treated and DMH-treated rats regarding the size, cellularity, and number of lymphoid aggregates per rat. A significant association (P less than .001) was seen between tumor development and the presence of a lymphoid aggregate in a given segment of the colon. Sessile adenocarcinomas, but not polypoid tumors, were significantly associated (P less than .001) with lymphoid aggregates and usually presented as mucinous tumors adjacent to or intermixed with the lymphoid tissue. PMID:6592387

  13. Phosphated crosslinked guar for colon-specific drug delivery. II. In vitro and in vivo evaluation in the rat.

    PubMed

    Gliko-Kabir, I; Yagen, B; Baluom, M; Rubinstein, A

    2000-01-01

    Targeting of drugs to the colon, following oral administration, can be accomplished by the use of modified, biodegradable polysaccharides as vehicles. In a previous study, a crosslinked low swelling guar gum (GG) hydrogel was synthesized by reacting it with trisodium trimetaphosphate (STMP). In the present study the functioning of GG crosslinked products (GGP) as possible colon-specific drug carriers was analyzed by studying (a) the release kinetics of pre-loaded hydrocortisone from GGP hydrogels into buffer solutions with, or without GG degrading enzymes (alpha-galactosidase and beta-mannanase) and (b) direct measurements of the polymers' degradation in the cecum of conscious rats. The effect of GG diet on alpha-galactosidase and beta-mannanase activity in the cecum of the rat and GGP degradation was also measured. It was found that the product GGP-0.1 (loosely crosslinked with 0.1 equivalents of STMP) was able to prevent the release of 80% of its hydrocortisone load for at least 6 h in PBS, pH=6.4. When a mixture of alpha-galactosidase and beta-mannanase was added to the buffer solution, an enhanced hydrocortisone release was observed. In-vivo degradation studies in the rat cecum showed that despite the chemical modification of GG, it retained its enzyme-degrading properties in a crosslinker concentration-dependent manner. Eight days of GG diet prior to the study increased alpha-galactosidase activity in the cecum of the rat three-fold, compared to its activity without the diet. However, this increase in the enzyme activity was unable to improve the degradation of the different GGP products. The overall alpha-galactosidase activity in the rat cecum was found to be extracellular, while the activity of beta-mannanase was found to be bacterial cell-wall associated. It is concluded that because CG crosslinked with STMP can be biodegraded enzymatically and is able to retard the release of a low water-soluble drug, this polymer could potentially be used as a vehicle

  14. Levodopa acts centrally to induce an antinociceptive action against colonic distension through activation of D2 dopamine receptors and the orexinergic system in the brain in conscious rats.

    PubMed

    Okumura, Toshikatsu; Nozu, Tsukasa; Kumei, Shima; Takakusaki, Kaoru; Miyagishi, Saori; Ohhira, Masumi

    2016-02-01

    Levodopa possesses antinociceptive actions against several somatic pain conditions. However, we do not know at this moment whether levodopa is also effective to visceral pain. The present study was therefore performed to clarify whether levodopa is effective to visceral pain and its mechanisms. Visceral sensation was evaluated by colonic distension-induced abdominal withdrawal reflex (AWR) in conscious rats. Subcutaneously (80 mg/rat) or intracisternally (2.5 μg/rat) administered levodopa significantly increased the threshold of colonic distension-induced AWR in conscious rats. The dose difference to induce the antinociceptive action suggests levodopa acts centrally to exert its antinociceptive action against colonic distension. While neither sulpiride, a D2 dopamine receptor antagonist, nor SCH23390, a D1 dopamine receptor antagonist by itself changed the threshold of colonic distension-induced AWR, the intracisternally injected levodopa-induced antinociceptive action was significantly blocked by pretreatment with subcutaneously administered sulpiride but not SCH23390. Treatment with intracisternal SB334867, an orexin 1 receptor antagonist, significantly blocked the subcutaneously administered levodopa-induced antinociceptive action. These results suggest that levodopa acts centrally to induce an antinociceptive action against colonic distension through activation of D2 dopamine receptors and the orexinergic system in the brain. PMID:26883457

  15. Antioxidant and Anti-inflammatory Effects of Yam (Dioscorea batatas Decne.) on Azoxymethane-induced Colonic Aberrant Crypt Foci in F344 Rats

    PubMed Central

    Son, In Suk; Lee, Jeong Soon; Lee, Ju Yeon; Kwon, Chong Suk

    2014-01-01

    Yam (Dioscorea batatas Decne.) has long been used as a health food and oriental folk medicine because of its nutritional fortification, tonic, anti-diarrheal, anti-inflammatory, antitussive, and expectorant effects. Reactive oxygen species (ROS), which are known to be implicated in a range of diseases, may be important progenitors of carcinogenesis. The aim of this study was to investigate the modulatory effect of yam on antioxidant status and inflammatory conditions during azoxymethane (AOM)-induced colon carcinogenesis in male F344 rats. We measured the formation of aberrant crypt foci (ACF), hemolysate antioxidant enzyme activities, colonic mucosal antioxidant enzyme gene expression, and colonic mucosal inflammatory mediator gene expression. The feeding of yam prior to carcinogenesis significantly inhibited AOM-induced colonic ACF formation. In yam-administered rats, erythrocyte levels of glutathione, glutathione peroxidase (GPx), and catalase were increased and colonic mucosal gene expression of Cu/Zn-superoxide dismutase (SOD), Mn-SOD, and GPx were up-regulated compared to the AOM group. Colonic mucosal gene expression of inflammatory mediators (i.e., nuclear factor kappaB, inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor alpha, and interleukin-1beta) was suppressed by the yam-supplemented diet. These results suggest that yam could be very useful for the prevention of colon cancer, as they enhance the antioxidant defense system and modulate inflammatory mediators. PMID:25054106

  16. Human oral isolate Lactobacillus fermentum AGR1487 induces a pro-inflammatory response in germ-free rat colons

    PubMed Central

    Anderson, Rachel C.; Ulluwishewa, Dulantha; Young, Wayne; Ryan, Leigh J.; Henderson, Gemma; Meijerink, Marjolein; Maier, Eva; Wells, Jerry M.; Roy, Nicole C.

    2016-01-01

    Lactobacilli are thought to be beneficial for human health, with lactobacilli-associated infections being confined to immune-compromised individuals. However, Lactobacillus fermentum AGR1487 negatively affects barrier integrity in vitro so we hypothesized that it caused a pro-inflammatory response in the host. We compared germ-free rats inoculated with AGR1487 to those inoculated with another L. fermentum strain, AGR1485, which does not affect in vitro barrier integrity. We showed that rats inoculated with AGR1487 had more inflammatory cells in their colon, higher levels of inflammatory biomarkers, and increased colonic gene expression of pro-inflammatory pathways. In addition, our in vitro studies showed that AGR1487 had a greater capacity to activate TLR signaling and induce pro-inflammatory cytokines in immune cells. This study indicates the potential of strains of the same species to differentially elicit inflammatory responses in the host and highlights the importance of strain characterization in probiotic approaches to treat inflammatory disorders. PMID:26843130

  17. Effect of Lactobacillus acidophilus KFRI342 on the development of chemically induced precancerous growths in the rat colon.

    PubMed

    Chang, Jin-Hee; Shim, Youn Young; Cha, Seong-Kwan; Reaney, Martin J T; Chee, Kew Mahn

    2012-03-01

    Lactobacillus acidophilus KFRI342, isolated from the Korean traditional food kimchi, was investigated for its suitability as a dietary probiotic. The effects of L. acidophilus KFRI342 on the development of chemically induced (1,2-dimethylhydrazine; DMH) precancerous cytological changes of the colon were investigated in rats. Forty-five male F344 rats were randomly divided into three dietary groups. The control group received a high-fat diet (HF), a second group received a high-fat diet containing the carcinogen (HFC), and a final group received a high-fat diet containing the carcinogen and L. acidophilus KFRI342 (HFCL). L. acidophilus KFRI342 was administered orally three times per week at 2×10(9) c.f.u. ml(-1). L. acidophilus KFRI342 treatments decreased the number of Escherichia coli in faecal samples, the enzyme activities of β-glucuronidase and β-glucosidase, and plasma triglyceride concentration compared to the HF and HFC treatments (P<0.05). L. acidophilus KFRI342 consumption also decreased the ratio of aberrant crypts to aberrant crypt foci incidence and the number of aberrant crypts in HFCL rats. Therefore, L. acidophilus showed potential probiotic activity as an inhibitor of DMH-induced symptoms in live rats. Our in vivo studies indicate that L. acidophilus from kimchi may be suitable as a probiotic for human use. PMID:22034161

  18. PhyloChip microarray analysis reveals altered gastrointestinal microbial communities in a rat model of colonic hypersensitivity

    SciTech Connect

    Nelson, T.A.; Holmes, S.; Alekseyenko, A.V.; Shenoy, M.; DeSantis, T.; Wu, C.H.; Andersen, G.L.; Winston, J.; Sonnenburg, J.; Pasricha, P.J.; Spormann, A.

    2010-12-01

    Irritable bowel syndrome (IBS) is a chronic, episodic gastrointestinal disorder that is prevalent in a significant fraction of western human populations; and changes in the microbiota of the large bowel have been implicated in the pathology of the disease. Using a novel comprehensive, high-density DNA microarray (PhyloChip) we performed a phylogenetic analysis of the microbial community of the large bowel in a rat model in which intracolonic acetic acid in neonates was used to induce long lasting colonic hypersensitivity and decreased stool water content and frequency, representing the equivalent of human constipation-predominant IBS. Our results revealed a significantly increased compositional difference in the microbial communities in rats with neonatal irritation as compared with controls. Even more striking was the dramatic change in the ratio of Firmicutes relative to Bacteroidetes, where neonatally irritated rats were enriched more with Bacteroidetes and also contained a different composition of species within this phylum. Our study also revealed differences at the level of bacterial families and species. The PhyloChip is a useful and convenient method to study enteric microflora. Further, this rat model system may be a useful experimental platform to study the causes and consequences of changes in microbial community composition associated with IBS.

  19. Non-digestible fraction of cooked bean (Phaseolus vulgaris L.) cultivar Bayo Madero suppresses colonic aberrant crypt foci in azoxymethane-induced rats.

    PubMed

    Vergara-Castañeda, Haydé Azeneth; Guevara-González, Ramón Gerardo; Ramos-Gómez, Minerva; Reynoso-Camacho, Rosalía; Guzmán-Maldonado, Horacio; Feregrino-Pérez, Ana Angélica; Oomah, B Dave; Loarca-Piña, Guadalupe

    2010-12-01

    The non-digestible fraction (NDF) of common bean (Phaseolus vulgaris L.) cultivar Bayo Madero was evaluated for its chemopreventive effect on azoxymethane (AOM) induced aberrant crypt foci (ACF) in rats. Diets containing cooked beans (CB) or its non-digestible fraction (NDF) were fed to 72 male rats after 2 azoxymethane injections (15 mg kg(-1) of body weight once a week for 2 weeks). ACF number, short chain fatty acids (SCFA) and β-glucuronidase activity were measured in colon sections from rats sacrificed 7 weeks after the last AOM injection. Food intake and weight gain of rats were unaffected by CB and NDF. CB and NDF suppressed the AOM-induced formation of ACF (0.8 and 1.5 ACF/distal zone, respectively vs. 6.6 ACF/distal zone based on methylene blue stain) and lowered β-glucuronidase activity in cecal, colonic and fecal content compared to AOM group. SCFA production was not significantly different among fecal, cecal and colonic content. These results indicate that CB and NDF from Bayo Madero provide direct chemoprotection against early stage of azoxymethane (AOM)-induced colon cancer in rats. PMID:21776479

  20. Emodin via colonic irrigation modulates gut microbiota and reduces uremic toxins in rats with chronic kidney disease.

    PubMed

    Zeng, Yu-Qun; Dai, Zhenhua; Lu, Fuhua; Lu, Zhaoyu; Liu, Xusheng; Chen, Cha; Qu, Pinghua; Li, Dingcheng; Hua, Zhengshuang; Qu, Yanni; Zou, Chuan

    2016-04-01

    Gut microbiota plays a dual role in chronic kidney disease (CKD) and is closely linked to production of uremic toxins. Strategies of reducing uremic toxins by targeting gut microbiota are emerging. It is known that Chinese medicine rhubarb enema can reduce uremic toxins and improve renal function. However, it remains unknown which ingredient or mechanism mediates its effect. Here we utilized a rat CKD model of 5/6 nephrectomy to evaluate the effect of emodin, a main ingredient of rhubarb, on gut microbiota and uremic toxins in CKD. Emodin was administered via colonic irrigation at 5ml (1mg/day) for four weeks. We found that emodin via colonic irrigation (ECI) altered levels of two important uremic toxins, urea and indoxyl sulfate (IS), and changed gut microbiota in rats with CKD. ECI remarkably reduced urea and IS and improved renal function. Pyrosequencing and Real-Time qPCR analyses revealed that ECI resumed the microbial balance from an abnormal status in CKD. We also demonstrated that ten genera were positively correlated with Urea while four genera exhibited the negative correlation. Moreover, three genera were positively correlated with IS. Therefore, emodin altered the gut microbiota structure. It reduced the number of harmful bacteria, such as Clostridium spp. that is positively correlated with both urea and IS, but augmented the number of beneficial bacteria, including Lactobacillus spp. that is negatively correlated with urea. Thus, changes in gut microbiota induced by emodin via colonic irrigation are closely associated with reduction in uremic toxins and mitigation of renal injury. PMID:27003359

  1. Emodin via colonic irrigation modulates gut microbiota and reduces uremic toxins in rats with chronic kidney disease

    PubMed Central

    Lu, Fuhua; Lu, Zhaoyu; Liu, Xusheng; Chen, Cha; Qu, Pinghua; Li, Dingcheng; Hua, Zhengshuang; Qu, Yanni; Zou, Chuan

    2016-01-01

    Gut microbiota plays a dual role in chronic kidney disease (CKD) and is closely linked to production of uremic toxins. Strategies of reducing uremic toxins by targeting gut microbiota are emerging. It is known that Chinese medicine rhubarb enema can reduce uremic toxins and improve renal function. However, it remains unknown which ingredient or mechanism mediates its effect. Here we utilized a rat CKD model of 5/6 nephrectomy to evaluate the effect of emodin, a main ingredient of rhubarb, on gut microbiota and uremic toxins in CKD. Emodin was administered via colonic irrigation at 5ml (1mg/day) for four weeks. We found that emodin via colonic irrigation (ECI) altered levels of two important uremic toxins, urea and indoxyl sulfate (IS), and changed gut microbiota in rats with CKD. ECI remarkably reduced urea and IS and improved renal function. Pyrosequencing and Real-Time qPCR analyses revealed that ECI resumed the microbial balance from an abnormal status in CKD. We also demonstrated that ten genera were positively correlated with Urea while four genera exhibited the negative correlation. Moreover, three genera were positively correlated with IS. Therefore, emodin altered the gut microbiota structure. It reduced the number of harmful bacteria, such as Clostridium spp. that is positively correlated with both urea and IS, but augmented the number of beneficial bacteria, including Lactobacillus spp. that is negatively correlated with urea. Thus, changes in gut microbiota induced by emodin via colonic irrigation are closely associated with reduction in uremic toxins and mitigation of renal injury. PMID:27003359

  2. Dietary folate protects against the development of macroscopic colonic neoplasia in a dose responsive manner in rats.

    PubMed Central

    Kim, Y I; Salomon, R N; Graeme-Cook, F; Choi, S W; Smith, D E; Dallal, G E; Mason, J B

    1996-01-01

    BACKGROUND AND AIMS: Diminished folate status is associated with enhanced colorectal carcinogenesis. This study investigated the potential chemopreventive role of dietary folate in the dimethylhydrazine colorectal cancer model. SUBJECTS AND METHODS: Sprague-Dawley rats were fed diets containing either 0, 2 (daily dietary requirement), 8 or 40 mg folate/kg diet for 20 weeks. After five weeks of diet, rats were injected with dimethyl-hydrazine (44 mg/kg) weekly for 15 weeks. Fifteen weeks after the first injection of dimethylhydrazine, all rats were killed. Folate status was determined, and the entire colorectum from each rat was analysed for macroscopic and microscopic neoplasms. RESULTS: Plasma and colonic folate concentrations correlated directly with dietary folate levels (p < 0.005). The incidence of microscopic neoplasms was similar among the four groups. However, the incidence and the average number of macroscopic tumours per rat decreased progressively with increasing dietary folate levels up to 8 mg/kg diet (p < 0.05). In the strongly procarcinogenic milieu used in this study, folate supplementation at 20 times the basal requirement was associated with rates of macroscopic tumour development that were intermediate, and not statistically distinct, from rates observed at either 0 or 8 mg/kg diet. CONCLUSIONS: These data indicate that in this rat model, (a) increasing dietary folate up to four times the basal requirement leads to a progressive reduction in the evolution of macroscopic neoplasms from microscopic foci; and (b) folate supplementation beyond four times the requirement does not convey further benefit. PMID:9014775

  3. Cell proliferation measurement in cecum and colon of rats using scanned images and fully automated image analysis: validation of method.

    PubMed

    Persohn, E; Seewald, W; Bauer, J; Schreiber, J

    2007-08-01

    The purpose of this study was to establish and validate fully automatic measurement of cell proliferation on scanned images of rat cecum and colon. Tissue slides were taken from a 4-week mechanistic study and processed for BrdU immunohistochemistry. Four sections of the cecum and colon per slide were scanned with the Zeiss MIRAX SCAN and transferred to the Definiens eCognition Analyst LS5.0 system for evaluation. Two rule sets for automatic counting of BrdU-positive and negative nuclei from mucosal cells on the image tiles were created by Definiens, one for cecum, one for colon. For validation, manual counting of 16 randomly selected tiles from five different slides of colon and cecum was performed. Negative and positive cell nuclei were counted in each image tile by four different people. Comparison of results from manual counting with the automatic counting showed that the sum as well as single tile data and labeling index (LI) from automatic counting were within the range of manual counting results +/-10%. Automatic counting included only cell nuclei within the mucosa whereas muscularis and lymphoid tissue as well as wrinkles from tissue preparation were excluded. In addition, two data sets from automatic counting of the same image tile were compared: (1) data where image tiles with incorrect detection of mucosa were excluded from further calculation of LI and area, and (2) data where no visual check was performed and all measurements were included. Results were very similar for both data sets. The necessity of the manual correction may therefore be doubted. PMID:17467963

  4. Apparent synergism between radiation and the carcinogen 1,2-dimethylhydrazine in the induction of colonic tumors in rats

    SciTech Connect

    Sharp, J.G.; Crouse, D.A.

    1989-02-01

    We have evaluated the interaction of radiation and 1,2-dimethylhydrazine (DMH) with respect to colon carcinogenesis in the Fischer 344 rat and have demonstrated the utility of this model for future more detailed mechanistic studies. In initial experiments, single doses of abdomen-only radiation (9 Gy) or DMH (150 mg/kg) were employed alone or in combination. Radiation was administered 3.5 days prior to the DMH. At 8 months post-treatment, the incidence of DMH-induced colon tumors was doubled by prior radiation exposure. When the protocol was repeated employing a DMH dose of 135 mg/kg with a 6-month observation period, the incidence of tumors induced by DMH alone was reduced, but the combination of radiation plus DMH still resulted in an augmentation of tumor incidence. When the protocol of radiation plus DMH was repeated three times at monthly intervals, a 15-fold increase in tumor incidence (from 5 to 74%) was observed at 6 months post-treatment. This finding demonstrates an apparent synergy between the radiation and the chemical carcinogen. Throughout these studies, the appearance of carcinomas was associated with preexisting colonic lymphoid nodules. The reproducibility of tumor induction as well as range of tumor incidence generated by variations in this system may be adequately sensitive to examine the combination of much lower doses of radiation and/or chemical carcinogen. The relationship between existing lymphoid aggregates which alter local epithelial cell kinetics and which are associated with fenestrations in the basement membrane, and the development of colon cancer in congruent sites may assist in defining dose-response curves for combined agents as well as providing a system for evaluating the mechanisms underlying their interactions.

  5. Beta-escin inhibits colonic aberrant crypt foci formation in rats and regulates the cell cycle growth by inducing p21(waf1/cip1) in colon cancer cells.

    PubMed

    Patlolla, Jagan M R; Raju, Jayadev; Swamy, Malisetty V; Rao, Chinthalapally V

    2006-06-01

    Extracts of Aesculus hippocastanum (horse chestnut) seed have been used in the treatment of chronic venous insufficiency, edema, and hemorrhoids. Most of the beneficial effects of horse chestnut are attributed to its principal component beta-escin or aescin. Recent studies suggest that beta-escin may possess anti-inflammatory, anti-hyaluronidase, and anti-histamine properties. We have evaluated the chemopreventive efficacy of dietary beta-escin on azoxymethane-induced colonic aberrant crypt foci (ACF). In addition, we analyzed the cell growth inhibitory effects and the induction of apoptosis in HT-29 human colon cancer cell line. To evaluate the inhibitory properties of beta-escin on colonic ACF, 7-week-old male F344 rats were fed experimental diets containing 0%, 0.025%, or 0.05% beta-escin. After 1 week, the rats received s.c. injections of azoxymethane (15 mg/kg body weight, once weekly for 2 weeks) or an equal volume of normal saline (vehicle). Rats were continued on respective experimental diets and sacrificed 8 weeks after the azoxymethane treatment. Colons were evaluated histopathologically for ACF. Administration of dietary 0.025% and 0.05% beta-escin significantly suppressed total colonic ACF formation up to approximately 40% (P < 0.001) and approximately 50% (P < 0.0001), respectively, when compared with control diet group. Importantly, rats fed beta-escin showed dose-dependent inhibition (approximately 49% to 65%, P < 0.0001) of foci containing four or more aberrant crypts. To understand the growth inhibitory effects, HT-29 human colon carcinoma cell lines were treated with various concentrations of beta-escin and analyzed by flow cytometry for apoptosis and cell cycle progression. Beta-escin treatment in HT-29 cells induced growth arrest at the G1-S phase, which was associated with the induction of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1), and this correlated with reduced phosphorylation of retinoblastoma protein. Results also indicate that

  6. Effect of intraperitoneal cetuximab administration on colonic anastomosis and early postoperative adhesion formation in a rat model

    PubMed Central

    Kurt, Atilla; Karanlık, Hasan; Soylu, Sinan; Özgür, İlker; Soydinç, Hilal Oğuz; Duranyıldız, Derya; Olgaç, Vakur; Şen, Fatma; Asoğlu, Oktar

    2016-01-01

    Objective We aimed to evaluate the effect of intraperitoneal cetuximab administration on the healing of anastomosis and development of early adhesion formation in a rat model. Materials and Methods Twenty-four female rats were used. A colon segment was resected and end-to-end anastomosis was performed. The rats were randomized into three groups after the performance of colonic anastomosis and received 10 mL of intraperitoneal solution including study drugs after closure of abdominal cavity: normal saline was administered to the normal saline group (n=8), cetuximab (400 mg/m2) was administered to the postoperative 1 group (n=8) 1 day after surgery, and cetuximab (400 mg/m2) was administered to the peroperative group (n=8) during surgery. Results The mean adhesion grade was 2.63±0.92, and 0.50±0.76 and 0.63±0.74 for control and test groups, respectively. Cetuximab reduced adhesion formation in test groups (p<0.05). When all groups were compared, it was found that vascular endothelial growth factor levels decreased significantly only in the abdomen (p<0.05). Hydroxyproline levels and anastomosis bursting pressure were examined, and a statistical difference was found between groups (hydroxyproline p<0.05, bursting pressure p<0.05). However, when postoperative 1 day group was compared with the control group, it was found that there was no difference between groups according to these parameters (p>0.05), but when peroperative group was compared with the control group a significant decrease was observed in both parameters. Histopathological healing score was also evaluated. No statistical difference between groups was found. Conclusion Twenty-four hours later from the operation, intraperitoneal cetuximab therapy may be a safe and feasible treatment for metastatic colorectal patients. PMID:27528807

  7. Calcium and α-tocopherol suppress cured-meat promotion of chemically induced colon carcinogenesis in rats and reduce associated biomarkers in human volunteers123

    PubMed Central

    Martin, Océane CB; Santarelli, Raphaelle L; Taché, Sylviane; Naud, Nathalie; Guéraud, Françoise; Audebert, Marc; Dupuy, Jacques; Meunier, Nathalie; Attaix, Didier; Vendeuvre, Jean-Luc; Mirvish, Sidney S; Kuhnle, Gunter CG; Cano, Noel; Corpet, Denis E

    2013-01-01

    Background: Processed meat intake has been associated with increased colorectal cancer risk. We have shown that cured meat promotes carcinogen-induced preneoplastic lesions and increases specific biomarkers in the colon of rats. Objectives: We investigated whether cured meat modulates biomarkers of cancer risk in human volunteers and whether specific agents can suppress cured meat–induced preneoplastic lesions in rats and associated biomarkers in rats and humans. Design: Six additives (calcium carbonate, inulin, rutin, carnosol, α-tocopherol, and trisodium pyrophosphate) were added to cured meat given to groups of rats for 14 d, and fecal biomarkers were measured. On the basis of these results, calcium and tocopherol were kept for the following additional experiments: cured meat, with or without calcium or tocopherol, was given to dimethylhydrazine-initiated rats (47% meat diet for 100 d) and to human volunteers in a crossover study (180 g/d for 4 d). Rat colons were scored for mucin-depleted foci, putative precancer lesions. Biomarkers of nitrosation, lipoperoxidation, and cytotoxicity were measured in the urine and feces of rats and volunteers. Results: Cured meat increased nitroso compounds and lipoperoxidation in human stools (both P < 0.05). Calcium normalized both biomarkers in rats and human feces, whereas tocopherol only decreased nitro compounds in rats and lipoperoxidation in feces of volunteers (all P < 0.05). Last, calcium and tocopherol reduced the number of mucin-depleted foci per colon in rats compared with nonsupplemented cured meat (P = 0.01). Conclusion: Data suggest that the addition of calcium carbonate to the diet or α-tocopherol to cured meat may reduce colorectal cancer risk associated with cured-meat intake. This trial was registered at clinicaltrials.gov as NCT00994526. PMID:24025632

  8. Chemopreventive Effects of Azadirachta indica on Cancer Marker Indices and Ultrastructural Changes During 1,2-Dimethylhydrazine-Induced Colon Carcinogenesis in Rats.

    PubMed

    Liu, Ning; Sun, Bo; Wu, Peiwei; Wei, Xi

    2015-09-01

    The present study elucidated the prospective of Azadirachta indica supplementation, if any, in affording chemoprevention by modulating the altered cancer markers and ultrastructural changes in DMH-induced colorectal carcinogenesis in rats. The rats were segregated into four groups viz., normal control, DMH treated, A. indica treated, and DMH+AI treated. Initiation and induction of colon carcinogenesis were achieved through weekly subcutaneous injections of DMH (30 mg/kg body weight) for both 10 and 20 weeks. A. indica extract was supplemented to rats at a dose rate of 100 mg/kg body weight of animals thrice a week on alternative days, ad libitum for two different time durations of 10 and 20 weeks. The study observed a significant increase in the number of aberrant crypt foci in colons of DMH-treated rats at both the time intervals which were decreased significantly upon AI supplementation. Also, a significant increase was seen in the enzyme activity of alkaline phosphatase, which, however, was moderated upon AI administration to DMH-treated rats. Changes in the ultrastructural architecture of colonic cells were apparent following both the treatment schedules of DMH; however, the changes were prominent following 20 weeks of DMH treatment. The most obvious changes were seen in the form of altered nuclear shape and disruption of cellular integrity, which were appreciably improved upon AI supplementation. In conclusion, the study shows the chemopreventive abilities of AI against DMH-induced colorectal carcinogenesis in rats. PMID:25697750

  9. Influence of diet or intrarectal bile acid injections on colon epithelial cell proliferation in rats previously injected with 1,2-dimethylhydrazine

    SciTech Connect

    Glauert, H.P.; Bennink, M.R.

    1983-03-01

    The effects of varying colon bile acid concentrations on rat colon epithelial cell proliferation were studied. Bile acid concentrations were altered by intrarectally injecting either deoxycholic or lithocholic acid for 4 weeks or by increasing the dietary fat or fiber (wheat bran, agar, or carrageenan) intake for 4 weeks. 1,2-Dimethylhydrazine (DMH) was s.c. injected into half of the rats 1 week before treatments began. Colon epithelial cell proliferation was measured by (/sup 3/H)thymidine autoradiography of colon crypts. Rats injected with DMH had more DNA-synthesizing cells per crypt. Neither bile acid injection nor any of the diets altered the number of DNA-synthesizing cells per crypt. DMH injections, deoxycholic and lithocholic acid intrarectal injections, and dietary agar and wheat bran all increased the total number of cells per crypt. High fat diets and dietary carrageenan did not affect cell number. All diets containing fiber lowered total fecal bile acid concentrations, but increasing the fat content of the diet did not affect them. These results indicate that the bile acid injections and dietary agar and wheat bran induce a slight hyperplasia in the colon.

  10. Effects of hydrogen sulphide on motility patterns in the rat colon

    PubMed Central

    Gil, V; Parsons, SP; Gallego, D; Huizinga, JD; Jimenez, M

    2013-01-01

    Background and Purpose Hydrogen sulphide (H2S) is an endogenous gaseous signalling molecule with putative functions in gastrointestinal motility regulation. Characterization of H2S effects on colonic motility is crucial to establish its potential use as therapeutic agent in the treatment of colonic disorders. Experimental Approach H2S effects on colonic motility were characterized using video recordings and construction of spatio-temporal maps. Microelectrode and muscle bath studies were performed to investigate the mechanisms underlying H2S effects. NaHS was used as the source of H2S. Key Results Rhythmic propulsive motor complexes (RPMCs) and ripples were observed in colonic spatio-temporal maps. Serosal addition of NaHS concentration-dependently inhibited RPMCs. In contrast, NaHS increased amplitude of the ripples without changing their frequency. Therefore, ripples became the predominant motor pattern. Neuronal blockade with lidocaine inhibited RPMCs, which were restored after administration of carbachol. Subsequent addition of NaHS inhibited RPMCs. Luminal addition of NaHS did not modify motility patterns. NaHS inhibited cholinergic excitatory junction potentials, carbachol-induced contractions and hyperpolarized smooth muscle cells, but did not modify slow wave activity. Conclusions and Implications H2S modulated colonic motility inhibiting propulsive contractile activity and enhancing the amplitude of ripples, promoting mixing. Muscle hyperpolarization and inhibition of neurally mediated cholinergic responses contributed to the inhibitory effect on propulsive activity. H2S effects were not related to changes in the frequency of slow wave activity originating in the network of interstitial cells of Cajal located near the submuscular plexus. Luminal H2S did not modify colonic motility probably because of epithelial detoxification. PMID:23297830

  11. Effects of high-fat mixed-lipid diet and exercise on the antioxidant system in skeletal and cardiac muscles of rats with colon carcinoma.

    PubMed

    Perse, Martina; Injac, Rade; Strukelj, Borut; Cerar, Anton

    2009-01-01

    Epidemiological and experimental studies suggest that eating habits and a sedentary lifestyle play a critical role in the incidence of colon carcinoma. In order to investigate the effects of high-fat mixed-lipid (HFML) diet in conjunction with long-term swimming, the antioxidant capacity of skeletal and cardiac muscles were observed in rats with 1,2-dimethylhydrazine (DMH)-induced colon carcinoma. Male Wistar rats were randomly divided into one control group and four cancer groups: sedentary and swimming groups fed low fat corn oil diet and sedentary and swimming groups, fed a HFML diet. After 6 months of swimming, rats were sacrificed and the blood, cardiac and soleus muscle were taken for analysis. Serum cholesterol, triglyceride and glucose concentrations were measured and the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase as well as levels of malondialdehyde and glutathione were determined. The results showed that endurance swimming prevented lipid peroxidation in the soleus muscle of HFML diet rats due to elevated activities of antioxidant enzymes. On the other hand, increased lipid peroxidation in the hearts of all cancer groups indicated that DMH-induced colon carcinoma impaired the antioxidant status of the heart. This failure in heart tissue indicated that enhanced antioxidant capacity after regular physical activity is not sufficient to offset oxidative stress caused by DMH-induced colon carcinoma. PMID:19904015

  12. TRIBROMOMETHANE EXPOSURE AND DIETARY FOLATE DEFICIENCY IN THE FORMATION OF ABERRANT CRYPT FOCI IN THE COLONS OF F344/N RATS

    EPA Science Inventory

    TRIBROMOMETHANE EXPOSURE AND DIETARY FOLATE DEFICIENCY IN THE FORMATION OF ABERRANT CRYPT FOCI IN THE COLONS OF F344/N RATS

    David R. Geter', Tanya M. Moore', Michael H. George', Steve R. Kilburn', Gloria Huggins-Clark', James W. Allen', and Anthony B. DeAngelo' 'National H...

  13. THE INDUCTION OF ABERRANT CRYPT FOCI IN THE COLONS OF MALE F344/N RATS EXPOSED TO THIHALOMETHANE MIXTURES IN THE DRINKING WATER

    EPA Science Inventory


    THE INDUCTION OF ABERRANT CRYPT FOCI IN THE COLONS OF MALE F344/N
    RATS EXPOSED TO TRIHALOMETHANE MIXTURES IN THE DRINKING WATER

    The trihalomethanes (THM), bromoform (TBM) and bromodichloromethane (BDCM), administered by corn oil gavage were found to increase large...

  14. VEHICLE AND MODE OF ADMINISTRATION EFFECTS ON THE INDUCTION OF ABERRANT CRYPT FOCI IN THE COLONS OF MALE F344/N RATS EXPOSED TO BROMODICHLOROMETHANE

    EPA Science Inventory

    Vehicle and Mode of Administration Effects on the Induction of Aberrant Crypt Foci in the Colons of Male F344/N Rats Exposed to Bromodichloromethane.

    David R. Geter, Michael H. George, Tanya M. Moore, Steve Kilburn, Gloria Huggins-Clark, and Anthony B. DeAngelo. Submited ...

  15. Studies on polyamine and ornithine metabolism in rat colon: effects of two synergistically. Acting inducers of ornithine decarboxylase activity

    SciTech Connect

    Stanley, B.A.

    1987-01-01

    Ornithine decarboxylase (ODC) activity in rat colon mucosa was determined by the release of /sup 14/CO/sub 2/ from radiolabeled ornithine in the presence (total enzyme) or absence (holoenzyme) of added pyridoxal-5'-phosphate (PLP). Total leucine incorporation into acid-precipitable protein over 30 minute was calculated by dividing the /sup 3/H-leucine in protein by the specific activity of the intracellular leucine. Amino acids, polyamines, and PLP-semicarbazide were quantified by high pressure liquid chromatography. Ornithine aminotransaminase activity (OAT) was measured as the quantity of pyrolline (5-carboxy) produced from alpha-ketoglutarate and ornithine. After 10 weeks on a high or no vitamin B/sub 6/ diet, no change in basal ODC activity was seen; however, sodium deoxycholate instillation in vitamin B/sub 6/ deficient rats led to a large increase in total but not holo-ODC activity. In rats fed normal chow diet, no increases in mucosal PLP levels were seen after either treatment. Increases in general protein synthesis rate could not account for the peaks in ODC activity after either stimulus. Putrescine increases were proportional to peaks of ODC activity after either stimulus, while spermine levels remained depressed for 18 hours after starvation/refeeding. Ornithine levels were increased after either stimulus, and this increase was linked to decreases in OAT activity, indicating short-term coordination of overall ornithine metabolism to favor polyamine biosynthesis.

  16. Effect of non-steroidal anti-inflammatory drugs on the increasing the incidence of colonic anastomosis in rats

    PubMed Central

    Ji, Chengdong; Xiong, Yuanchang; Pan, Xin; Guo, Xuan; Li, Zhen; Qian, Shuwen; Xu, Chang; Yu, De-Hua; Liao, Wan-Qing

    2015-01-01

    Background: Anastomotic leakage is one of serious complications of colorectal surgery. Research is inconsistent about whether non-steroidal anti-inflammatory drugs influence the healing of colorectal anastomoses and increase the incidence of anastomotic leakage. Objective: To study the influence of NSAIDs on the healing of rat colonic anastomoses. Design: This was an animal randomized-control trial. This study was approved by the ethical committee of Yangpu Hospital, Tongji University. Intervention: 90 healthy Sprague-Dawley rats were randomly divided into 6 groups of 15 rats/group. Trail was performed in C (cotrol group) with no drugs, group M with morphine for analgesia, group F with flurbiprofen axeil, group L with lornoxicam, and group P with parecoxib sodium. Main outcome measures: The main outcomes measures were serological indexes including vascular endothelial growth factor, prostaglandin E2, hydroxyproline, and C reactive protein; histological specimens from the anastomotic stoma tissue including the collagen proportion, and hydroxyproline, cycloxygenase-2, and vascular endothelial growth factor content; physical indicators, including stoma fracture pressure, fracture strength and anastomotic leakage. Results: No significant difference was observed among the indices of each group (P > 0.05). A significant difference occurred after operation (P < 0.05), with the data for groups K and M being dramatically higher than those for group F. Limitation: The study was nonblinded. Conclusion: The postoperative usages of non-steroidal anti-inflammatory drugs can decrease the strength of anastomotic tissue, and increase the incidence of anastomotic leakage. PMID:26261490

  17. Anti-proliferative and Apoptotic Effects of Basella rubra (L.) Against 1, 2-Dimethyl Hydrazine-induced Colon Carcinogenesis in Rats.

    PubMed

    Kilari, Bhanu Priya; Kotakadi, Venkata Subbaiah; Penchalaneni, Josthna

    2016-01-01

    Colorectal cancer is a very prevalent diagnosed cancer. The current study was performed in order to examine the role of BRAE (Basella rubra aqueous extract) in regulating aberrant crypt foci (ACF) formation, cell proliferation and inhibition of apoptosis in a colon carcinogenesis model in male Wistar rats. Rats were randomly allocated into six groups. Group I served as control, and group II acted as a drug control administered BRAE (250mg/kg b.w.) orally for 30 weeks. Rats in group III-VI were given subcutaneous injections of DMH (25mg/kg b.w. weekly) for 15 weeks to initiate colon carcinogenesis. Those in group IV and VI were administered BRAE along with DMH injections. Rats in group V were administered with BRAE after cessation of DMH injection. After 30 weeks of experimental period colons were obtained from experimental groups and analyzed for ACF incidence, argyrophilic nucleolar organizing region- associated proteins (AgNOR) count, histopathological and immunohistochemical changes. Only in DMH exposed groups were ACF and AgNOR numbers increased. Administration of BRAE appreciably decreased the numbers of ACF and AgNOR in BRAE treated groups. Histopathological findings revealed a high level of dysplastic changes with decreased number of goblet cells found only in only DMH injected rats. Administration of BRAE in treated group rats reversed these changes. Expression markers for cell proliferation (PCNA and Ki67) were elevated in DMH treated rats, but reduced with BRAE treatement. This expression was reversed with apoptosis markers (p53 and Caspase-3). Thus the results results of the present study were found to be significant and confirmed the potential efficacy of BRAE against colon carcinogenesis. PMID:26838257

  18. Effects of differing purified cellulose, pectin, and hemicellulose fiber diets on fecal enzymes in 1,2-dimethylhydrazine-induced rat colon carcinogenesis.

    PubMed

    Freeman, H J

    1986-11-01

    The fecal microflora enzymes, beta-glucuronidase and beta-glucosidase, as well as fecal bacterial counts, were examined during colon carcinogenesis in rats administered parenteral 1,2-dimethylhydrazine and fed nutritionally equivalent diets free of fiber or containing one of three single sources of dietary fiber (cellulose, hemicellulose, and pectin). Whereas pectin-fed animals had increased fecal beta-glucuronidase activities, those fed cellulose and hemicellulose, two fibers protective in dimethylhydrazine colon neoplasia, had decreased activities. Although fecal bacterial counts were not significantly changed, similar differential changes in fecal beta-glucosidase activity were noted: cellulose but not pectin or hemicellulose feeding was associated with reduced activity. Although cellulose fiber may cause differing physiological effects resulting in a reduction in colonic neoplasia development in this experimental animal model, decreased bacterial metabolic enzyme activation of carcinogens or cocarcinogens may lead to diminished exposure of colonic cells to exogenous or endogenous mutagens. PMID:3019527

  19. Bioluminescent imaging reveals novel patterns of colonization and invasion in systemic Escherichia coli K1 experimental infection in the neonatal rat.

    PubMed

    Witcomb, Luci A; Collins, James W; McCarthy, Alex J; Frankel, Gadi; Taylor, Peter W

    2015-12-01

    Key features of Escherichia coli K1-mediated neonatal sepsis and meningitis, such as a strong age dependency and development along the gut-mesentery-blood-brain course of infection, can be replicated in the newborn rat. We examined temporal and spatial aspects of E. coli K1 infection following initiation of gastrointestinal colonization in 2-day-old (P2) rats after oral administration of E. coli K1 strain A192PP and a virulent bioluminescent derivative, E. coli A192PP-lux2. A combination of bacterial enumeration in the major organs, two-dimensional bioluminescence imaging, and three-dimensional diffuse light imaging tomography with integrated micro-computed tomography indicated multiple sites of colonization within the alimentary canal; these included the tongue, esophagus, and stomach in addition to the small intestine and colon. After invasion of the blood compartment, the bacteria entered the central nervous system, with restricted colonization of the brain, and also invaded the major organs, in line with increases in the severity of symptoms of infection. Both keratinized and nonkeratinized surfaces of esophagi were colonized to a considerably greater extent in susceptible P2 neonates than in corresponding tissues from infection-resistant 9-day-old rat pups; the bacteria appeared to damage and penetrate the nonkeratinized esophageal epithelium of infection-susceptible P2 animals, suggesting the esophagus represents a portal of entry for E. coli K1 into the systemic circulation. Thus, multimodality imaging of experimental systemic infections in real time indicates complex dynamic patterns of colonization and dissemination that provide new insights into the E. coli K1 infection of the neonatal rat. PMID:26351276

  20. High-resolution time-of-flight mass spectrometry fingerprinting of metabolites from cecum and distal colon contents of rats fed resistant starch

    SciTech Connect

    Anderson, Timothy J.; Jones, Roger W.; Ai, Yongfeng; Houk, Robert S.; Jane, Jay-lin; Zhao, Yinsheng; Birt, Diane F.; McClelland, John F.

    2013-12-04

    Time-of-flight mass spectrometry along with statistical analysis was utilized to study metabolic profiles among rats fed resistant starch (RS) diets. Fischer 344 rats were fed four starch diets consisting of 55 % (w/w, dbs) starch. A control starch diet consisting of corn starch was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. A subgroup received antibiotic treatment to determine if perturbations in the gut microbiome were long lasting. A second subgroup was treated with azoxymethane (AOM), a carcinogen. At the end of the 8-week study, cecal and distal colon content samples were collected from the sacrificed rats. Metabolites were extracted from cecal and distal colon samples into acetonitrile. The extracts were then analyzed on an accurate-mass time-of-flight mass spectrometer to obtain their metabolic profile. The data were analyzed using partial least-squares discriminant analysis (PLS-DA). The PLS-DA analysis utilized a training set and verification set to classify samples within diet and treatment groups. PLS-DA could reliably differentiate the diet treatments for both cecal and distal colon samples. The PLS-DA analyses of the antibiotic and no antibiotic-treated subgroups were well classified for cecal samples and modestly separated for distal colon samples. PLS-DA analysis had limited success separating distal colon samples for rats given AOM from those not treated; the cecal samples from AOM had very poor classification. Mass spectrometry profiling coupled with PLS-DA can readily classify metabolite differences among rats given RS diets.

  1. Dietary olive oil supplemented with fish oil, rich in EPA and DHA (n-3) polyunsaturated fatty acids, attenuates colonic inflammation in rats with DSS-induced colitis.

    PubMed

    Camuesco, Desirée; Gálvez, Julio; Nieto, Ana; Comalada, Mònica; Rodríguez-Cabezas, M Elena; Concha, Angel; Xaus, Jordi; Zarzuelo, Antonio

    2005-04-01

    Previous studies proposed a protective role of the dietary intake of (n-3) PUFA in human inflammatory bowel disease (IBD), but almost no studies have been performed using olive oil. The aims of the present study were to test the beneficial effects of an olive oil-based diet with or without fish oil, rich in (n-3) PUFA, in the dextran sodium sulfate (DSS) model of rat colitis and to elucidate the mechanisms involved in their potential beneficial effects, with special attention to the production of some of the mediators involved in the intestinal inflammatory response, such as leukotriene B(4) (LTB(4)), tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO). Rats were fed the different diets for 2 wk before colitis induction and thereafter until colonic evaluation 15 d later. Colitic rats fed the olive oil-based diet had a lower colonic inflammatory response than those fed the soybean oil diet, and this beneficial effect was increased by the dietary incorporation of (n-3) PUFA. A restoration of colonic glutathione levels and lower colonic NO synthase expression occurred in all colitic rats fed an olive oil diet compared with the control colitic group that consumed the soybean oil diet. However, (n-3) PUFA incorporation into an olive oil diet significantly decreased colonic TNFalpha and LTB(4) levels compared with colitic rats that were not supplemented with fish oil. These results affirm the benefits of an olive oil diet in the management of IBD, which are further enhanced by the addition of (n-3) PUFA. PMID:15795419

  2. Apple Flavonoid Phloretin Inhibits Escherichia coli O157:H7 Biofilm Formation and Ameliorates Colon Inflammation in Rats ▿ †

    PubMed Central

    Lee, Jin-Hyung; Regmi, Sushil Chandra; Kim, Jung-Ae; Cho, Moo Hwan; Yun, Hyungdon; Lee, Chang-Soo; Lee, Jintae

    2011-01-01

    Pathogenic biofilms have been associated with persistent infections due to their high resistance to antimicrobial agents, while commensal biofilms often fortify the host's immune system. Hence, controlling biofilm formation of both pathogenic bacteria and commensal bacteria is important in bacterium-related diseases. We investigated the effect of plant flavonoids on biofilm formation of enterohemorrhagic Escherichia coli O157:H7. The antioxidant phloretin, which is abundant in apples, markedly reduced E. coli O157:H7 biofilm formation without affecting the growth of planktonic cells, while phloretin did not harm commensal E. coli K-12 biofilms. Also, phloretin reduced E. coli O157:H7 attachment to human colon epithelial cells. Global transcriptome analyses revealed that phloretin repressed toxin genes (hlyE and stx2), autoinducer-2 importer genes (lsrACDBF), curli genes (csgA and csgB), and dozens of prophage genes in E. coli O157:H7 biofilm cells. Electron microscopy confirmed that phloretin reduced fimbria production in E. coli O157:H7. Also, phloretin suppressed the tumor necrosis factor alpha-induced inflammatory response in vitro using human colonic epithelial cells. Moreover, in the rat model of colitis induced by trinitrobenzene sulfonic acid (TNBS), phloretin significantly ameliorated colon inflammation and body weight loss. Taken together, our results suggest that the antioxidant phloretin also acts as an inhibitor of E. coli O157:H7 biofilm formation as well as an anti-inflammatory agent in inflammatory bowel diseases without harming beneficial commensal E. coli biofilms. PMID:21930760

  3. Telmisartan attenuates colon inflammation, oxidative perturbations and apoptosis in a rat model of experimental inflammatory bowel disease.

    PubMed

    Arab, Hany H; Al-Shorbagy, Muhammad Y; Abdallah, Dalaal M; Nassar, Noha N

    2014-01-01

    Accumulating evidence has indicated the implication of angiotensin II in the pathogenesis of inflammatory bowel diseases (IBD) via its proinflammatory features. Telmisartan (TLM) is an angiotensin II receptor antagonist with marked anti-inflammatory and antioxidant actions that mediated its cardio-, reno- and hepatoprotective actions. However, its impact on IBD has not been previously explored. Thus, we aimed to investigate the potential alleviating effects of TLM in tri-nitrobenezene sulphonic acid (TNBS)-induced colitis in rats. Pretreatment with TLM (10 mg/kg p.o.) attenuated the severity of colitis as evidenced by decrease of disease activity index (DAI), colon weight/length ratio, macroscopic damage, histopathological findings and leukocyte migration. TLM suppressed the inflammatory response via attenuation of tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE2) and myeloperoxidase (MPO) activity as a marker of neutrophil infiltration besides restoration of interleukin-10 (IL-10). TLM also suppressed mRNA and protein expression of nuclear factor kappa B (NF-κB) p65 and mRNA of cyclo-oxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) proinflammatory genes with concomitant upregulation of PPAR-γ. The alleviation of TLM to colon injury was also associated with inhibition of oxidative stress as evidenced by suppression of lipid peroxides and nitric oxide (NO) besides boosting glutathione (GSH), total anti-oxidant capacity (TAC) and the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). With respect to apoptosis, TLM downregulated the increased mRNA, protein expression and activity of caspase-3. It also suppressed the elevation of cytochrome c and Bax mRNA besides the upregulation of Bcl-2. Together, these findings highlight evidences for the beneficial effects of TLM in IBD which are mediated through modulation of colonic inflammation, oxidative stress and apoptosis. PMID:24831514

  4. The Involvement of Ca2+ Signal Pathways in Distal Colonic Myocytes in a Rat Model of Dextran Sulfate Sodium-induced Colitis

    PubMed Central

    Wang, Yan; Li, Jun-Xia; Ji, Guang-Ju; Zhai, Kui; Wang, Hua-Hong; Liu, Xin-Guang

    2016-01-01

    Background: Disrupted Ca2+ homeostasis contributes to the development of colonic dysmotility in ulcerative colitis (UC), but the underlying mechanisms are unknown. This study aimed to examine the alteration of colonic smooth muscle (SM) Ca2+ signaling and Ca2+ handling proteins in a rat model of dextran sulfate sodium (DSS)-induced UC. Methods: Male Sprague-Dawley rats were randomly divided into control (n = 18) and DSS (n = 17) groups. Acute colitis was induced by 5% DSS in the drinking water for 7 days. Contractility of colonic SM strips (controls, n = 8 and DSS, n = 7) was measured in an organ bath. Cytosolic resting Ca2+ levels (n = 3 in each group) and Ca2+ transients (n = 3 in each group) were measured in single colonic SM cells. Ca2+ handling protein expression was determined by Western blotting (n = 4 in each group). Differences between control and DSS groups were analyzed by a two-sample independent t-test. Results: Average tension and amplitude of spontaneous contractions of colonic muscle strips were significantly enhanced in DSS-treated rats compared with controls (1.25 ± 0.08 g vs. 0.96 ± 0.05 g, P = 0.007; and 2.67 ± 0.62 g vs. 0.52 ± 0.10 g, P = 0.013). Average tensions of carbachol-evoked contractions were much weaker in the DSS group (1.08 ± 0.10 g vs. 1.80 ± 0.19 g, P = 0.006). Spontaneous Ca2+ transients were observed in more SM cells from DSS-treated rats (15/30 cells) than from controls (5/36 cells). Peak caffeine-induced intracellular Ca2+ release was lower in SM cells of DSS-treated rats than controls (0.413 ± 0.046 vs. 0.548 ± 0.041, P = 0.033). Finally, several Ca2+ handling proteins in colonic SM were altered by DSS treatment, including sarcoplasmic reticulum calcium-transporting ATPase 2a downregulation and phospholamban and inositol 1,4,5-trisphosphate receptor 1 upregulation. Conclusions: Impaired intracellular Ca2+ signaling of colonic SM, caused by alteration of Ca2+ handing proteins, contribute to colonic dysmotility in DSS

  5. Chemopreventive effects of Strobilanthes crispus leaf extract on azoxymethane-induced aberrant crypt foci in rat colon

    PubMed Central

    Al-Henhena, Nawal; Khalifa, Shaden A. M.; Ying, Rozaida Poh Yuen; Hassandarvish, Pouya; Rouhollahi, Elham; Al-Wajeeh, Nahla Saeed; Ali, Habibah Mohd; Abdulla, Mahmood Ameen; El-Seedi, Hesham R.

    2015-01-01

    In this work, microscopic and histological studies suggest that Strobilanthes crispus ethanol extract reduce azoxymethane (AOM)-induced colonic aberrant crypt foci (ACF) in rats. S. crispus is considered a traditional medicine and used as an antioxidant. Its leaf contains a large amount of phenolic compounds to which its radical scavenging role is attributed and enhance its ability to eradicate oxidative stress reactions. The study was designed to determine the chemopreventive effect of S. crispus ethanol extract in vivo and in vitro by elucidating the effect of the extract on intermediate biomarkers which can be used as effective predictors of colon cancer. S. crispus was analyzed for DPPH free radical scavenging, nitric oxide (NO) and ferric acid reduction. The results indicated that S. crispus oral administration significantly inhibited colorectal carcinogenesis induced by AOM as revealed by the reduction in the number of ACF. S. crispus down-regulated the expression of PCNA, Bcl2 and β-catenin. Additionally, it exerted a pronounced inhibitory effect on MDA and NO levels and stimulatory effect on CAT and GPx activities. These results demonstrate that S. crispus is a chemopreventive agent for colorectal cancer through the suppression of early and intermediate carcinogenic phases that may be related to its flavonoid content. PMID:26307342

  6. Fibrin glue protection of primary anastomosis in the obstructed left colon. An experimental study on the rat.

    PubMed

    Hulkko, O A; Haukipuro, K A; Laitinen, S T

    1988-01-01

    A left-sided colon obstruction was produced with a polypropylene sling in 65 rats. Colon resection and primary anastomosis were performed three days later. The animals were then randomly allocated to the FG (fibrin glue) group receiving sealing of the anastomosis with 0.4 ml of fibrin glue (Beriplast R), or to the NG (non-glue) group. The anastomoses were assessed 30 min, two days and four days later. Adhesion formation was similar in both groups. The number of macroscopic or radiological leakages did not differ either. At 30 min the mean bursting pressure was 74.6 +/- 8.6 (SD) mmHg in the FG group and 58.3 +/- 21.6 mmHg in NG (non-glue) group (p less than 0.05, Mann-Whitney test). Later on the strength of the anastomoses was equal in both groups. We conclude that the initial sealing of weak points in the anastomoses was beneficial but the inherent strength per se could not be enhanced. PMID:2451367

  7. Increased oxygen consumption caused by cAMP- and Ca(2+)-mediated chloride secretion in rat distal colon.

    PubMed

    Saraví, Fernando D; Cincunegui, Liliana M; Saldeña, Teobaldo A; Carra, Graciela E; Ibáñez, Jorge E

    2005-01-01

    Epithelial ion transport is dependent on ATP supply provided by aerobic metabolism. In the rat distal colon chloride secretion accounts for the largest portion of electrogenic transport measured as the short-circuit current (I(SC)). Inhibition of basal chloride secretion decreases epithelial oxygen consumption (QO2) in this tissue, while serotonin (5-hydroxytryptamine) proportionally increases both Isc and QO2. The effect of serotonin in this tissue is mainly mediated by 5HT4 receptors linked to adenylate cyclase through a stimulant G protein (GS). This work assessed whether the chloride secretion-induced increase in QO2 is a common characteristic of secretagogues, which act through either cAMP-dependent or Ca(2+)-dependent mechanisms. The effects of phosphodiesterase inhibitor 3-isobutyl-1-methylxantine (IBMX) and muscarinic agonist carbachol (both 0.1 mmol/L) were studied in rat distal colon isolated mucosa mounted in an Ussing chamber adapted for continuous measurement of oxygen concentration, allowing determination of QO2. Baseline I(SC) and QO2 were compared with I(SC) and QO2 after addition of either serotonin as an active control, IBMX, carbachol or IBMX plus carbachol. Each drug increased proportionally Isc and QO2. Although the effect of IBMX alone was modest and that of carbachol was short-lived, a synergic effect on Isc and QO2 was seen when both drugs were simultaneously added. Linear regression analysis showed a significant correlation between increases in I(SC) and QO2 (r2 = 0.746; P < 0.0001). Thus, stimulation of chloride secretion increases QO2 regardless of the intracellular pathway involved. These results extend previous findings, corroborating the close coupling between chloride secretion and QO2 in this epithelium. PMID:15954731

  8. Exon-specific DNA hypomethylation of the p53 gene of rat colon induced by dimethylhydrazine. Modulation by dietary folate.

    PubMed Central

    Kim, Y. I.; Pogribny, I. P.; Salomon, R. N.; Choi, S. W.; Smith, D. E.; James, S. J.; Mason, J. B.

    1996-01-01

    Folate deficiency enhances colorectal carcinogenesis in dimethylhydrazine-treated rats. Folate is an important mediator of DNA methylation, an epigenetic modification of DNA that is known to be dysregulated in the early stages of colorectal cancer. This study investigated the effect of dimethylhydrazine on DNA methylation of the colonic p53 gene and the modulation of this effect by dietary folate. Sprague-Dawley rats were fed diets containing 0, 2, 8, or 40 mg of folate/kg of diet. Five weeks after diet initiation, dimethylhydrazine was injected weekly for fifteen weeks. Folate-depleted and folate-replete control animals did not receive dimethylhydrazine and were fed the 0- and 8-mg folate diets, respectively. The extent of p53 methylation was determined by a quantitative HpaII-polymerase chain reaction. In exons 6 and 7, significant p53 hypomethylation was observed in all dimethylhydrazine-treated rats relative to controls (P < 0.01), independent of dietary folate. In exon 8, significant p53 hypomethylation was observed only in the dimethylhydrazine-treated folate-depleted rats compared with controls (P = 0.038) and was effectively overcome by increasing levels of dietary folate (P = 0.008). In this model, dimethylhydrazine induces exon-specific p53 hypomethylation. In some exons, this occurs independent of dietary folate, and in others, increasing levels of dietary folate effectively override the induction of hypomethylation in a dose-responsive manner. This may be a mechanism by which increasing levels of dietary folate inhibit colorectal carcinogenesis. PMID:8863662

  9. Effects of liquid paraffin in the diet or infused via colonic enema on fecal elimination of /sup 14/C-hexachlorobenzene from body burdens in rats

    SciTech Connect

    Robles-Porras, H.

    1985-01-01

    Twenty-one male rats were dosed once intraperitoneally with 32.2 mg /sup 14/C-hexachlorobenzene in corn oil (/sup 14/C-HCB activity 11.67 ..mu..Ci/rat). After 4 d, six rats were randomly selected, bled and hemi-castrated with sampling of epididymal adipose tissue to establish /sup 14/C-HCB body burdens. Thereafter, all rats were allocated randomly into three groups, each with five intact and two hemi-castrated rats. One group (controls) received only a basal diet; another received the basal diet amended with 5% light mineral oil (MO); and the third received the basal diet and 1 ml of MO once daily via enema in the upper colon. Treatments were continued throughout 27 d. Excretion of /sup 14/C-HCB and(or) metabolites into feces and urine was measured daily for each rat for 31 d after /sup 14/C-HCB dosage. Fecal excretion of /sup 14/C-HCB and(or) metabolites was increased 2.5-fold by dietary MO and 1.7-fold by MO in the colon. When adjusted to equal dosage, MO by colon was 93% as effective as MO by diet. Urinary /sup 14/C-HCB excretion was not affected by MO, except indirectly through lowered body burden. Addition of hexadecane (25 ..mu..l per 100 mg adipose tissue) into the incubation mixture enhanced (P < 0.05) distribution of /sup 14/C-HCB into the liquid fraction for rats not previously fed hexadecane, but had no effect on incubation mixtures from rats fed hexadecane. Results confirm that liquid paraffins enhance elimination of /sup 14/C-HCB from body burdens into feces and suggest that distribution into blood cells and plasma may partially explain the effect.

  10. Intestinal handling of bisacodyl and picosulphate by everted sacs of the rat jejunum and stripped colon.

    PubMed

    Hillestad, B; Sund, R B; Buajordet, M

    1982-10-01

    Bisacodyl (BIS) is the acetic acid di-ester of the laxative diphenol 2-(4,4'-dihydroxydiphenyl)methyl-pyridine. A HPLC-method which permits the simultaneous determination of BIS and its monodesacetylated (MONO) as well as totally desacetylated (DES) form, has been used to study the intestinal handling of BIS (20 nmol/ml), when the compound was incubated for 60 min. at the mucosal side of the preparations specified. In the jejunal mucosal fluid, BIS disappeared completely in short time, and there was a nearly equivalent rise in DES. MONO was transitory present. Hydrolysis was also rapid in mucosal fluid which had been in contact with jejunal sacs for 30 sec., but BIS was stable in blank incubations. Hydrolysis of BIS was slower by colonic than by jejunal sacs, and all three molecular forms were present during incubation. It seemed still slower in mucosal fluid which had been in contact with colonic sacs for 5 min. BIS just as DES accumulated in the jejunal and colonic serosal fluid mainly as conjugates (greater than 95%), and DES was in all cases the only unconjugated metabolite present. Drug accumulation in jejunal serosal fluid was the same whether BIS or DES was added. However, more drug seemed to accumulate on the serosal side of colonic sacs when incubated with BIS instead of DES. In similar experiments with picosulphate, which is the sulphuric acid di-ester analogue of BIS, free DES was not detected in the mucosal fluid during incubation. The amounts of laxative accumulating in the serosal fluid were less than 1/10 of those observed with BIS. PMID:7180502