【Animal Modeling】-Rat diarrhea-type irritable bowel syndrome model

  OBJECTIVE: On the basis of observing the changes of rat symptoms, histopathology, visceral susceptibility, mast cell activation, autophagy, beclin-1 and claudin-2 and other related indicators, capsaicin is supplemented. The study of a new model of diarrhea-dominated irritable bowel syndrome (D-IBS), which can assess comprehensive restraint pressure.

   Method: 40 clean-grade male SD rats were divided into normal group, group I, group II and group III according to their body weight, with 10 rats in each group. In the model group, the D-IBS model was established by using restraining tail clamping force and capsaicin combined with intragastric administration (0.125% in group I, 0.250% in group II, and 0.500% in group III). weekly. Powerlab was used to detect the contraction of the rat's abdominal wall and the number of dorsal arches through optical and electron microscopes, and the mast cell stain (magenta-orange G method) was used to detect the activation of mast cells. Used to detect the pathology and autonomy of rat colon. In order to detect the changes in the expression of beclin-1 and claudin-2 in the colonic mucosa of rats, the changes of phage were detected by immunohistochemistry SABC.

  Result: All rats in the model III group died, the number of feces in the second group increased, and the visceral sensitivity threshold decreased. Compared with the normal group and the model group I, the difference was statistically significant (P\u003c0.05). Rats in each group. Colonic mucosa, mucosal epithelial villi and glands were normal in shape, and submucosal vasodilatation and diffuse inflammatory infiltration were unchanged. Except for the normal group, the mucosal matrix or submucosa of the colon tissues of the model groups I and II were round purple-red. Until the dark purple staining, it showed that the expression of mast cells in the colon epithelial cells of the model II rats increased; autophagy, beclin-1 and claudin-2 expression increased significantly. .. Compared with the normal group and the model I group, the difference is significant (P\u003c0.05).

   Conclusion: The rat D-IBS model established by the combination of restraint stress and 0.25% capsaicin forced feeding showed increased diarrhea, visceral hypersensitivity, increased mast cell expression, increased intestinal epithelial cell autophagy and intestinal mucosa. Indicates barrier destruction. Like human IBS, this method is simple in function, easy to implement, and worthy of widespread use.