Effects Of Xiaojianzhong Tang Based On Thermosensitive Channel TRPA1 On Intestinal Motility Of Colitis In Rats

Background:Xiaojianzhong tang comes from shanghanlun,which is included in the theory of prescriptions.It is one of the representative prescriptions of warm and cold dispelling agent,and is often used in the clinical treatment of abdominal pain and diarrhea caused by deficiency-cold of middle-jiao.This prescription is composed of Cinnamon Twig,peony,ginger,jujube,caramel and liquor ice.It has the effect of warming,tonifying deficiency,and slowing down.Xiaojianzhong tang is used of treatment of chronic gastritis,gastric and duodenal ulcer,ulcerative colitis,irritable bowel syndrome,intestinal spasm and other syndromes of deficiency-cold of middle-jiao now in China.These diseases are often characterized by pain and diarrhea.Modern studies have shown that the thermosensitive channel TRPA1 on the chromaffin cells of the intestinal wall is a detector for intestinal irritants.When the stimulus is detected,serotonin(5-HT)is released,and 5-HT acts on the specific receptor 5-HT3R and 5-HT4R to promote intestinal peristalsis and excrete irritants.It has been shown that a variety of compounds that activate TRPA1 can be isolated from the constituent drugs of Xiaojianzhong tang.Therefore,Xiaojianzhong tang may exert a therapeutic effect by regulating TRPA1.The purpose of this study was to investigate the role of TRPA1 in the treatment of colitis and the regulation of intestinal peristalsis by highfat diet in rats,using charcoal advancement method,histopathology,and immunohistochemistry methods.Objective:1.To observe the effect of Xiaojianzhong tang on small intestine propulsion rate.2、To observe the effect of Xiaojianzhong tang on colon histopathology of rats induced by high fat diet.3.To observe the expression changes of TRPA1,5-HT,5-HT3R and 5-HT4R in the colonic mucosa of colitis rats,and to preliminarily explore their role in intestinal peristalsis in colitis.Methods:48 Wistar male rats weighing 200 ± 10g were randomly divided into 6 groups:normal group,model group,Xiaojianzhong tang low dose group,Xiaojianzhong tang middle dose group,Xiaojianzhong tang high dose group and mesalazine group(positive control).The rats in the model group and the drug group were given 45%high fat diet buffet for 8 weeks.Xiaojianzhong granule(2.025g/kg·d、4.05g/kg·d、8.1g/kg·d)and mesalazine(0.135g/kg·d)were administrated to the low,middle and high dose group and the positive control group respectively for 2 weeks.The body weight of the rats was measured after the model was established successfully.The changes of the body weight of the rats before and after the administration were observed.The peristalsis reaction of the small intestine was observed in the gastrointestinal motility experiment 0.5h before the sampling.The length of colon was measured to observe the degree of colon injury,the pathological changes of colon tissues were observed by HE staining,and the expression of TRPA1,5-HT,5-HT3R and 5-HT4R in colon tissues were detected by immunohistochemistry.Results:(1)Xiaojianzhong tang can slow down intestinal peristalsis.Small intestine propulsion of rats:compared with the normal group,the small intestine propulsion rate of rats in the model group increased significantly(P<0.01);compared with the model group,the small intestine propulsion rate of rats in the low-dose Xiaojianzhong Decoction group was lower with difference(P<0.05);the small intestine propulsion rate of rats in the high,middle and mesalazine groups of Xiaojianzhong tang decreased significantly(P<0.01).(2)Histopathological changes,he staining results showed:Compared with the normal group,the intestinal epithelial cells of model group showed edema and inflammatory cell infiltration.Compared with the model group,the high,medium and low dose groups of Xiaojianzhong Decoction and mesalazine group can improve the pathological changes of jejunum and colon,which indicates that Xiaojianzhong decoction can reduce intestinal inflammatory reaction.(3)Changes of TRPA1 pathway related indicators:immune histochemistry showed:TRPA1,5-HT,5-HT3R and 5-HT4R were expressed in jejunum and colon of rats.The positive expression of TRPA1 in jejunum and colon of high-fat diet model group was significantly higher than that of normal group,which indicated that high-fat diet induced intestinal inflammation could induce TRPA1 activation and increase the release of 5-HT,5-HT3R and 5-HT4R.The expression levels of TRPA1,5-HT,5-HT3R and 5-HT4R in jejunum and colon tissue of rats were decreased in low,medium and high dose of Xiaojianzhong Decoction and positive control group.Conclusion and significance:Xiaojianzhong tang can reduce colonic inflammatory response and intestinal peristalsis induced by high fat diet in rats.This effect may be achieved by Xiaojianzhong tang through inhibiting or desensitizing TRPA1 channel in colon,reducing the release of 5-HT,and then inhibiting its effect on 5-HT3R and 5-HT4R.