Objective: To observe the effect of electroacupuncture (EA) on mast cell activation-related substances and intestinal barrier function in diarrhea-predominant irritable bowel syndrome (IBS-D) model rats, so as to explore its underlying mechanisms.
Methods: Thirty female SD rats were randomly divided into control group, model group and EA group, with 10 rats in each group. IBS-D model was established by chronic unpredictable mild stress combined with senna solution gavage. Rats in the EA group received EA treatment (2 Hz/15 Hz，0.1-1.0 mA) at "Zusanli" (ST36), "Taichong"(LR3) and "Tianshu"(ST25), 20 min per day, for a total of 14 days, with sides alternated daily. Visceral pain threshold was used to evaluate visceral hypersensitivity, diarrhea index was used to evaluate diarrhea degree. After all treatments, the pathological scores of colon were recorded after HE staining, the contents of cholecystokinin (CCK), substance P (SP), tryptase (TPS) and adenosine triphosphate (ATP) in colon were detected by ELISA, and the expressions of colonic tight junction protein ZO-1 and occludin were detected by Western blot.
Results: Compared with the control group, the visceral pain threshold, the expression levels of colonic ZO-1 and occludin proteins decreased (P<0.01), while the diarrhea index, the contents of colonic CCK, SP, TPS and ATP were significantly increased (P<0.01) in the model group. After intervention, in comparison with the model group, the visceral pain thre-shold, the protein expression levels of colonic ZO-1 and occludin protein increased (P<0.01), while the diarrhea index, the contents of colonic CCK, SP, TPS and ATP were significantly decreased (P<0.01) in the EA group.
Conclusion: EA can significantly alleviate the symptoms of visceral hypersensitivity and diarrhea in IBS-D rats. Its mechanism may be related to down-regulating colonic CCK, SP, TPS and ATP, inhibiting mast cell activation and degranulation, and up-regulating colonic barrier tight junction proteins.
目的：观察电针对腹泻型肠易激综合征(IBS-D)模型大鼠肠道屏障功能及肥大细胞活化相关物质表达水平的影响，并探讨其可能机制。方法：SD雌性大鼠随机分为空白对照组、模型组与电针组，每组10只。采用慢性不可预知性温和应激联合番泻叶灌胃复制IBS-D模型。电针组大鼠给予电针“足三里”“太冲”“天枢”，每日选用一侧穴位，左右交替，连续14 d。采用内脏痛阈值评价大鼠内脏高敏状态，腹泻指数评价大鼠腹泻程度，HE染色法观察结肠病理变化，ELISA法检测大鼠结肠胆囊收缩素(CCK)、P物质(SP)、类胰蛋白酶(TPS)与三磷酸腺苷(ATP)的含量，Western blot法检测大鼠结肠紧密连接蛋白ZO-1、Occludin的蛋白表达水平。结果：与空白对照组比较，模型组大鼠内脏痛阈值降低(P<0.01)，腹泻指数升高(P<0.01)，结肠组织中CCK、SP、TPS、ATP含量升高(P<0.01)，结肠组织中ZO-1、Occludin蛋白表达水平降低(P<0.01)。与模型组比较，干预后电针组大鼠内脏痛阈值升高(P<0.01)，腹泻指数下降(P<0.01)，结肠组织中CCK、SP、TPS、ATP含量降低(P<0.01)，结肠组织中ZO-1、Occludin蛋白表达水平升高(P<0.01)。各组大鼠结肠病理检测未见异常。结论：电针可以显著缓解IBS-D大鼠内脏高敏与腹泻等症状，其机制可能与下调肥大细胞活化相关物质，上调肠道屏障紧密连接蛋白有关。.
Keywords: Diarrhea-predominant irritable bowel syndrome; Electroacupuncture; Gut barrier; Mast cell; Tight junction.