OBJECTIVE: To study the effect of total alkaloids of Dendrobium officinale on insulin resistance in diabetic rats with non-alcoholic fatty liver disease (NAFLD).
METHODS: SD rats were fed with high-fat and high-sugar diet for 4 weeks and then given intraperitoneal injection of streptozotocin (STZ) 40 mg/kg to establish a rat model of diabetes combined with NAFLD. The model rats were randomly divided into model group and DNLA 20 mg/kg kg group, DNLA40mg/kg group, DNLA80mg/kg group and metformin 100mg/kg group, 10 rats in each group. Simultaneously, 10 SD rats were set up as blank control. After 4 weeks of intragastric administration, abdominal aortic blood was collected to detect rats Fasting blood glucose (FPG) and fasting insulin (FINS) levels were calculated, insulin resistance index (HOMA-IR) was calculated, morphological changes of liver and pancreas were observed by H.E. staining, and insulin levels in islets were detected by immunohistochemistry.
Results: The FPG, FINS and HOMA-IR of the model rats were significantly increased (P<0.05); compared with the model group, the FPG, FINS and HOMA-IR of the DNLA40mg/kg group and the DNLA80mg/kg group were significantly decreased (P<0.05). The liver tissue of diabetic rats suffered from steatosis, and pancreatic islet atrophy was observed under H.E. staining microscope, and the number of cells in the islet decreased. Compared with the model group, the DNLA40mg/kg group and the DNLA80mg/kg group had less liver steatosis, and more cells in the islet. Compared with the model group, the insulin expression in the islets of the DNLA 40 mg/kg group and the DNLA 80 mg/kg group increased to varying degrees.
Conclusion: DNLA can reduce blood glucose and alleviate liver steatosis in diabetic rats with NAFLD, and the mechanism is related to the improvement of insulin resistance.