Changes in gut microbiota, metabolite SCFAs, and GPR43 expression in obese diabetic mice after sleeve gastrectomy

Aims To evaluate changes in short-chain fatty acid levels and G protein-coupled receptor 43 expression and distribution in gut microbiota and explore their relationships in obese diabetic mice after sleeve gastrectomy. Methods and Results Diet-induced obese mice and obese diabetic ob/ob mice were established. Changes in glucose metabolism, lipid metabolism, gut microbiota, metabolite short-chain fatty acids, and G protein-coupled receptor 43 expressions were assessed in both models 10 weeks postoperatively. Mice that underwent sleeve gastrectomy exhibited sustained weight loss and reduced glucose, insulin, leptin, and cholesterol levels. Metagenomic sequencing revealed significant characteristic alterations in gut microbiota after sleeve gastrectomy, which were correlated with changes in faecal short-chain fatty acid levels. Postoperatively, G protein-coupled receptor 43 expression in the colon tissue was upregulated in both models, whereas its expression in the adipose tissue was downregulated in the diet-induced obese mouse model. Conclusions Metabolic improvement in obese and diabetic mice after sleeve gastrectomy is associated with alterations in gut microbiota, short-chain fatty acid levels, and G protein-coupled receptor 43 expressions. Significance and Impact of Study Our findings reveal a possible mechanism through which sleeve gastrectomy improves obesity and diabetes via changes in bacteria producing short-chain fatty acids and G protein-coupled receptor 43.