APETx2及粪菌移植对母婴分离诱导肠易激综合征大鼠内脏敏感性的影响及机制

目的 探讨粪菌移植对母婴分离诱导的肠易激综合征（IBS）大鼠内脏敏感性的影响并观察酸敏感离子通道3（ASIC3）抑制剂APETx2对其作用及可能机制。方法 取SD孕鼠10只，待其生产后取仔鼠，采用母婴分离法构建IBS模型，收集建模成功的大鼠粪便制成粪菌液。18只健康雄性SD大鼠按照随机数字表法分为正常对照（Con）组、母婴分离（NMS）组、NMS+APETx2 处理组，每组 6 只。NMS 组、NMS+APETx2 组均予以含有抗生素的鸡尾酒（ABX-water）连续灌胃5 d，构建伪无菌鼠模型，之后给予NMS大鼠粪菌液（1.6 mL/kg）灌胃；Con组给予等体积生理盐水灌胃，每天1次，连续灌胃5 d。灌胃结束后，NMS+APETx2组给予100 μg/kg APETx2连续腹腔注射7 d，每天1次。采用墨汁推进实验测定肠道推进率，结直肠扩张刺激后评估内脏敏感性。免疫组化染色法检测结肠组织中ASIC3、c-kit蛋白表达。分离3组大鼠结肠cajal间质细胞（ICC），显微镜观察细胞形态学和数量变化。结果 与Con组比较，NMS组肠道推进率减慢，腹部回撤反射（AWR）评分升高，内脏敏感性增加，结肠组织ASIC3、c-kit表达上调，ICC形态改变。与NMS组相比，NMS+APETx2组肠道推进率加快，AWR评分下降，内脏敏感性降低，结肠组织ASIC3、c-kit表达下调，ICC形态趋于正常，数量明显减少。结论 IBS粪菌移植可以诱导内脏高敏感发生和降低肠道传输速率，APETx2可改善其内脏敏感性和肠道传输速率，其机制可能与APETx2下调ASIC3表达、抑制与ICC相关的c-kit信号有关。

Effects and mechanism of APETx2 and fecal bacteria transplantation on the visceralsensitivity of rats with irritable bowel syndrome induced by neonatal maternal separation

Objective To investigate the effect of fecal bacterial transplantation on visceral sensitivity of rats withirritable bowel syndrome (IBS) induced by neonatal maternal separation (NMS), and the role of acid-sensitive ion channel 3(ASIC3) inhibitor APETx2 on visceral sensitivity in the development of IBS. Methods Ten pregnant SD rats were taken,and the IBS model was constructed by NMS after the birth. The feces of the successful model rats were collected to makefecal microbiota solution. Eighteen healthy male SD rats were randomly divided into the normal control group (Con group),the neonatal maternal separation group (NMS group) and the NMS+APETx2 treatment group, 6 rats for each group. TheNMS group and NMS+APETx2 group were given ABX-water continuously for 5 days to establish the pseudo-aseptic modelrats, then NMS rats were given intragastric administration of fecal microbiota solution (1.6 mL/kg). The Con group was giventhe equal volume of normal saline consecutively for 5 days, once a day. After the gavage, the NMS+APETx2 group was given100 μg/kg APETx2 continuous intraperitoneal injection for 7 days, once a day. The ink movement test was used to determinethe intestinal transit rate, and the visceral sensitivity was evaluated after colorectal balloon distention (CRD) stimulation.Immunohistochemistry was performed to detect the localization of ASIC3 and c-kit, and the changes of morphology andnumber of Cajal cells were observed. Results Compared with the Con group, the NMS group had slower intestinal transitrate, increased visceral sensitivity with the higher abdominal withdrawal reflex (AWR) scores, promoted expression of ASIC3 and c-kit in colon tissue, and morphological changes of ICC cells. Compared with the NMS group, there were significantlyaccelerated intestinal transit rate, decreased sensitivity of the intestine with the lower AWR scores, suppressed ASIC3 and ckit expression in colon tissue, and the morphology tended to be normal and the number of ICC was reduced in the NMS+APETx2 group. Conclusion Fecal bacteria transplantation from IBS can induce visceral hypersensitivity and reduceintestinal transmission. APETx2 can alleviate visceral sensitivity and intestinal transmission, which may be related to theinhibition of ASIC3 expression and down-regulation of the c-kit signal associated Cajal cells.