枯草芽孢杆菌通过TGR5/TRPA1信号通路调节慢性传输型便秘小鼠的肠蠕动

目的 探究枯草芽孢杆菌对慢性传输型便秘(slow transit constipation，STC)小鼠5-HT释放及TGR5/TRPA1信号通路的影响，以明确其对STC的治疗作用及机制。方法 24只♂C57BL/6小鼠分为对照组、模型组、枯草芽孢杆菌治疗组和INT-777组。复方地芬诺酯用于构建STC小鼠模型，枯草芽孢杆菌治疗组和INT-777组于复方地芬诺酯灌胃1 h后分别灌胃枯草芽孢杆菌悬液和INT-777，连续14 d。实验期间统计小鼠24 h排便量、粪便含水量和肠道推进率；HE染色观察结肠病变程度；ELISA和免疫荧光检测结肠5-HT的表达；Western blotting检测结肠TGR5/TRPA1通路蛋白的表达。结果 与对照组相比，模型组小鼠24 h排便量、粪便含水量和肠道推进率均显著降低(P<0.01或P<0.001)，表现出肠蠕动障碍和结肠病理损伤；枯草芽孢杆菌和INT-777显著改善了肠蠕动障碍和结肠病理损伤。另外，模型组小鼠5-HT的释放和TGR5/TRPA1通路被抑制，而枯草芽孢杆菌和INT-777显著增加了STC小鼠结肠组织中5-HT的表达(P<0.05或P<0.001)，激活了TGR5/TRPA1通路。结论 枯草芽孢杆菌可能通过上调TGR5/TRPA1通路并促进肠嗜铬细胞释放5-HT调节STC小鼠肠蠕动，对STC发挥较好的治疗作用。

Bacillus Subtilis Regulates Intestinal Peristalsis in Mice with Slow Transit Constipation Through the TGR5/TRPA1 Signaling Pathway

OBJECTIVE To explore the effects of Bacillus subtilis on the release of 5-HT and the TGR5/TRPA1 signaling pathway in mice with slow transit constipation(STC), so as to clarify the therapeutic effect and mechanism of Bacillus subtilis on STC. METHODS Twenty-four male C57BL/6 mice were divided into control group, model group, Bacillus subtilis group and INT-777 group. STC mouse model was established by compound diphenoxylate, and Bacillus subtilis suspension and INT-777 were gavaged after 1 h compound diphenoxylate treatment, respectively, for 14 d. The 24 h defecation volume, fecal water content and intestinal transport rate of mice were counted during the experiment. HE staining was used to observe the histological morphology and pathological degree of colon. The expression of 5-HT in colon was detected by ELISA and immunofluorescence, and the protein expressions of TGR5/TRPA1 pathway were detected by Western blotting. RESULTS It was found that compared with the control group, the 24 h defecation volume, fecal water content and intestinal transit rate in the model group were significantly decreased(P<0.01 or P<0.001), showing intestinal peristalsis disorder and pathological lesions of the colon. Bacillus subtilis and INT-777 significantly improved intestinal peristalsis and pathological damage of colon. In addition, the release of 5-HT(P<0.05 or P<0.001) and the TGR5/TRPA1 signaling pathway in the model group were inhibited, while Bacillus subtilis and INT-777 significantly increased the expression of 5-HT and activated the TGR5/TRPA1 pathway in STC mice. CONCLUSION Bacillus subtilis regulates intestinal peristalsis of STC mice by upregulating the TGR5/TRPA1 signaling pathway and promoting the release of 5-HT from enterochromaffin cells, thus playing a good role in the treatment of STC.