Effects Of Berberine Oil Visceral Hypersensitivity In A Rat Model Of Irritable Bowel Syndrome

Part Ⅰ Establishment and Evaluation of a Rat Model ofIrritable Bowel SyndromeObjectives To explore the method of establishment of a rat model of irritablebowel syndrome (IBS)．Methods The rat model of IBS was induced by the intracolonic administration ofacetic acid. The visceral sensitivity was evaluated by the score of abdominal withdrawalreflexes（AWR）in the model group（n=10）and the control group（n=10）. Defecationparameters were evaluated by RSP. Toluidine blue staining was used to measure mastcells in colon of rats. The expression level of c-fos in the colon was showed byimmunohistochemical staining and analyzed semi-quantitatively by computerized colorimage analyzer.Results The character of this model matched the character of IBS. The score ofAWR in model group was significantly higher than that of control group (P＜0.05). Also,the rats in model group defecated more stools than those in control group. The expressionlevel of mast cells and c-fos in the colon in model group was greater than those in controlgroup (P＜0.05).Conclusions The rat model of IBS which was established by intracolonicadministration of acetic acid showed the character of visceral hypersensitivity. And thehyperexpression level of mast cell and c-fos in the colon was probably involved in thepathophysiology of visceral hypersensitivity. Part Ⅱ Effects of Berberine on Visceral Hypersensitivity in aRat Model of Irritable Bowel SyndromeObjectives To study the effects of berberine(BBR) on visceral hypersensitivity ina rat model of irritable bowel syndrome(IBS) and provide a useful medicine in ourexperimental studies.Methods The rat model of IBS was induced by intracolonic administration ofacetic acid. Fourty rats were divided randomly into four groups: control group(withouttreatments served as controls，n=10), saline group(3ml physiological saline administeredvia gastric tube after induction of enema， n=10), BBR group （3ml BBR solution,50mg/Kg,administered via gastric tube after induction of enema，n=10）,pinaverium group（3ml pinaverium solution,150mg/Kg, administered via gastric tube after induction ofenema，n=10）. The visceral sensitivity was evaluated by the score of AWR in each group.Defecation parameters were evaluated by RSP. The expression level of5-HT in the colonand IL-6in blood plasma was showed by ELISAmethod.Results There was significantly different in the score of AWR, defecationparameters, the level of5-HT and IL-6among each group (P＜0.05). There wassignificantly different among saline group, BBR group and pinaverium group in the scoreof AWR, defecation parameters, the level of5-HT and IL-6(P＜0.05). There wassignificantly different in the score of AWR, defecation parameters, the level of5-HT andIL-6between BBR group and pinaverium group (P＜0.05).Conclusions The results indicated that the protective effects of BBR on visceralhypersensitivity in a rat model of IBS. Part Ⅲ Potential Mechanism of Berberine on VisceralHypersensitivity in a Rat Model of Irritable Bowel SyndromeObjectives To study potential mechanism of berberine(BBR) on visceralhypersensitivity（VH） in a rat model of irritable bowel syndrome(IBS).Methods The rat model of IBS was induced by the intracolonic administration ofacetic acid. Fifty rats were divided randomly into five groups: control group(withouttreatments served as controls), saline group(3ml physiological saline administered viagastric tube after induction of enema), BBR group （3ml BBR solution,50mg/Kg,administered via gastric tube after induction of enema）, aminoguanidine group（aminoguanidine,100mg/kg, via intraperitoneal injection after induction of enema）andBBR+aminoguanidine group(3ml BBR solution,50mg/Kg, administered via gastric tubeafter induction of enema, and then were treated with aminoguanidine,100mg/kg, viaintraperitoneal injection). The visceral sensitivity was evaluated by the score of AWR ineach group. Defecation parameters were evaluated by RSP. The expression level ofD-lactic acid in blood plasma was showed by ELISA method and the expression level ofTJ proteins(occluding and ZO-1) in the colon was showed by western blot analysis.Results The rats in saline group showed VH response to rectal distension(P＜0.05)and defecated more stools than control rats (P＜0.05), whereas berberine treatmentsignificantly attenuated VH and effectively reduced defecation. Aminoguanidine reducedthe protective effects of BBR on VH. A pronounced increase in epithelial permeabilityand decreased expression of tight junction proteins (occludin, ZO-1) in saline group wasprevented by BBR, but not aminoguanidine. BBR administration reduced thehypersensitivity, defecation, colonic permeability and increased the expression of tightjunction proteins (occludin, ZO-1).Conclusions The results indicated the protective effects on visceral hypersensitivity in a rat model of irritable bowel syndrome and as the part of this effectwas lowered by NOS inhibitor, NO might play a role in the protective effect of BBR tosome extent.