动物造模 z-bio 2021-08-05 576

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

　　Method: 24 SD rats were randomly divided into a blank group and a chronic stress model group. The rats in the model group were stimulated by accidental stress for 9 consecutive days. After modeling, 5 rats in each of the normal group and the model group were randomly selected, and stool samples were collected to analyze the diversity of intestinal flora. Of 12 rats in each group, 4 rats 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 weight gain of rats in the model group was significantly lower than that in the normal group (P=0.001). The content of corticosterone in the adrenal tissue of the model group was significantly lower than that of rats (P=0.006), and the content of plasma corticosterone in the model group was higher than that of the normal group (P=0.006, P=0.025). (2) After 9 days, The arrangement of epithelial cells in the gastric mucosa of the model group was sparser than that of the normal group, and the thickness was less than that of the normal group (P=0.034). The number of neutrophils. The gastric lamina propria of the model group was lower than that of the normal group, but the number of neutrophils in the colonic mucosa of the model group was higher than that of the normal group (P=0.016). The number of neutrophils in the model group was higher than that in the normal group (P=0.013). 3) After 9 days of chronic unpredictable stress, α diversity analysis showed that OTU strains in stool samples of the model group were significantly increased compared with the normal rat group (P=0.001). The ratio of desulfovibrio to Helicobacter pylori in the rat samples of the model group was higher than that of the normal group (P=0.011, P=0.047). The proportion of Bacteroides in the mouse model group was significantly lower than that in the normal group. A group of mice. The difference is statistically significant (P = 0.001).

　　Conclusion: 9d unpredictable stress stimulation can create a stable chronic stress rat model. The immunosuppression caused by chronic stress occurs simultaneously with the imbalance of the intestinal flora of rats.