The effects of diet and streptozotocin on metabolism and gut microbiota in a type 2 diabetes mellitus mouse model

Diabetes mellitus is a metabolic disorder disease. Diabetes models can be established using diet and/or chemical agents. However, the effects of these methods on the intestinal microbiota are poorly understood. In this study, C57BL/6 mice were fed with a high-fat or high-sucrose-fat diet (HFD/HSFD), followed by 1 or 2 injections of streptozotocin (STZ) to induce type 2 diabetes mellitus. HFD-fed mice showed more severe dyslipidemia compared to HSFD-fed mice. The abundance of Bacteroidetes decreased in HFD-fed mice compared to HSFD-fed mice. After STZ injection, all the mice developed more severe hyperglycaemia, particularly in HFD-fed mice. Although the compositions of intestinal microbiota between the diet- and STZ-induced mice were similar, STZ injection increased the abundance of <i>Ruminiclostridium</i> and <i>[Eubacterium] oxidoreducens</i> and decreased the abundance of <i>PrevotellaceaeUCG_001</i>. In summary, HFD and HSFD had different metabolic phenotypes and gut microbiota. Diets play a more vital role than STZ injection in reshaping gut microbiota.