维生素D对2型糖尿病小鼠肠道菌群的影响

Objective: To investigate the effect of 1,25 (OH)2D3 on intestinal microbiota in type 2 diabetic mice. Methods: A high-fat diet supplemented with STZ was used to establish the type 2 diabetes mellitus model, and the dose of 5 μg/kg vitamin D was used for intervention. The glucose metabolism indicators (fasting blood glucose, glycosylated hemoglobin, insulin, glucose tolerance) of mice in each group were detected. The release of serum inflammatory factors IL-1β, TNF-α and lipopolysaccharide were detected by ELISA. The pathological changes of pancreatic tissue were observed by HE staining. The differences in the diversity and structural composition of the intestinal microbiota of mice were detected by 16SrDNA amplicon pyrosequencing. Spearman correlation analysis was used to detect the correlation between differential bacterial and biochemical parameters. Results: Compared with the control group, the glucose metabolism in type 2 diabetic mice was significantly abnormal, manifested as increased levels of FBG and GHbAlc, decreased insulin secretion, accompanied by increased release of inflammatory factors in serum and aggravated islet damage. The results of 16SrDNA amplicon pyrosequencing showed that the diversity and structural composition of the intestinal microbiota in T2DM mice were changed, and the Bacteroides, Enterococcus, Enterobacter, Muribaculaceae, Alistipes and Mucispirillum were more enriched. Interestingly, these bacteria were significantly correlated with biochemical parameters. After vitamin D intervention, the glucose metabolism of T2DM mice was improved, the inflammatory response was alleviated, and the islet damage was relieved. In addition, vitamin D also changed the composition of intestinal microbiota, down-regulated Bacteroidetes, Enterococcus and Enterobacter, and enriched Lachnospiraceae_UCG_006. Conclusion: T2DM is accompanied by impaired glucose tolerance and systemic inflammatory response, which may be related to changes in the composition of intestinal microbiota and the enrichment of pathogenic bacteria such as Enterobacter and Enterococcus. However, vitamin D intervention enriches beneficial bacteria, effectively controls the inflammatory response, and alleviates abnormal glucose metabolism.