Effect of metformin on the formation of hepatic fibrosis in type 2 diabetic rats

The aim of this study is to investigate the effects of the metformin on the formation of hepatic   fibrosis in type 2 diabetic rats and discuss its mechanism of liver-protecting activity.  After SD rats were fed with high-fat and high-sucrose diet for four weeks, low-dose streptozotocin (STZ) was injected intraperitoneally to make the animal mode of type 2 diabetes.  Then, all diabetic rats was fed with the high-fat diet and metformin (ig, 100 mg·kg⁻¹) was given orally to metformin group for four months.  After the last administration, fasting blood glucose was determined.  The livers were removed to calculate the hepatic coefficient and to make HE and Picro acid-Sirius red staining, immunohistochemistry (α-SMA and TGFβ1) and TUNEL staining in order to evaluate the effect of metformin on the hepatic fibrosis.  The animal model of type 2 diabetes with hepatic  fibrosis was successfully made.  Metformin can significantly alleviate the lesions of hepatic steatosis and    fibrosis, markedly reduce the expressions of α-SMA and TGFβ1 in liver tissue of type 2 diabetic rats.  However, TUNEL staining result suggested that metformin could not reduce apoptosis of hepatocytes.  The results suggest that meformin can inhibit the formation of hepatic fibrosis in type 2 diabetes.