动物造模 z-bio 2022-07-07 394

　　Objective To analyze the effects of unpredictable stress on the gastrointestinal immune system and microbial population by observing the rats after 9 days of unpredictable stress stimulation, so as to provide reference for the study of chronic stress on gastrointestinal function.

　　Methods Twenty-four SD rats were randomly divided into blank group and chronic stress model group. Rats in the model group received unexpected stress stimulation for 9 consecutive days. After the modeling was completed, 5 rats in the normal group and the model group were randomly selected, and fecal samples were collected for the analysis of intestinal microbial diversity. Of the 12 rats in each group, 4 were randomly selected for perfusion fixation, and gastric antrum and colon tissues were collected for morphological observation; the plasma and adrenal tissues of the remaining 8 rats were collected to detect the content of corticosterone.

　　Results (1) After 9 days of unpredictable stress stimulation, the 9-day body weight gain of the rats in the model group was significantly lower than that of the rats in the normal group (P=0.001). Compared with the normal group, the plasma corticosterone content of the rats in the model group increased (P=0.025). (2) After 9 days, the arrangement of gastric mucosal epithelial cells in the model group was sparser than that in the normal group, and its thickness was reduced compared with the normal group (P=0.034); the gastric mucosal lamina propria neutrophils in the model group were Compared with the normal group, the number of neutrophils decreased (P=0.016); the number of neutrophils in the colonic mucosa of the model group was increased compared with the normal group (P=0.013). 3) After 9 days of chronic unpredictable stress, the Alpha diversity analysis showed that the bacterial species in the OTU of the fecal samples of the rats in the model group increased significantly compared with the rats in the normal group (P=0.001); The proportion of Vibrio and Helicobacter was increased compared with that of the normal group (P= 0.011, P= 0.047); the proportion of Bacteroidetes in the model group was significantly decreased compared with the normal group. , the difference was highly statistically significant (P = 0.001).

　　Conclusion 9-day unpredictable stress stimulation can create a stable chronic stress rat model, and the immunosuppression caused by chronic stress is accompanied by the imbalance of intestinal microflora in rats.