The Protective Effects Of Water Extract Of Radix Isatidis In Diabetic Rats And Its Complications

Objective:Establish a model of type 2 diabetic rats, and study the protective effects of water extract of Radix Isatidis (WERI) on rats with type 2 diabetes mellitus and its complications. Then we discussed the possible mechanism.Methods:After one week of adaptive feeding of Wistar male rats, Eight rats were selected randomly as the control group, they were fed with normal diet. Others were fed with high glucose and high fat diet. Eight weeks later, diabetic rats were induced by streptozotocin (STZ, 25mg·kg-1). The diabetic rats were randomly divided into five groups:the model group, rosiglitazone group (RSG, 0.3mg·kg-1), WERI high dose group (WERI, 100mg·kg-1), WERI middle dose group (50, mg·kg-1) and low dose group (WERI,25mg·kg-1). RSG and WERI groups of diabetic rats were administered orally once time a day. Observe the general state of rats, weighing once a week. Four weeks of administration later, serum total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), free fatty acid (FFA), aspartate aminotransferase (AST), alanine aminotransferase (ALT) of every goup were measured by automatic biochemical analyzer. Fasting blood glucose (FBG) in all rats were measured by glucose oxidase method. Fasting blood insulin levels (FINS) were measured by radioimmunoassay. Insulin sensitivity index (ISI) of rats were calculated according to the formula. Malondialdehyde (MDA) content of rats were measured by thiobarbituric acid method.Superoxide dismutase (SOD) of rats were measured by WST-8 method. Liver coefficient of rats were calculated according to the formula. The serum adiponectin (ADP), monocyte chemotaxis protein -1 (MCP-1) and endothelin -1 (ET-1) concentration were measured by ELISA. Nitric oxide (NO) concentration was measured by nitrate reductase method. Nitric oxide synthase (NOS) catalyzes the reaction of L-Arg andmolecular oxygen to generate NO, NO and affinity substances could produce colored compounds, the activity of NOS was determined. The pathological changes of livers and aortas were observated by hematoxylin eosin stain. Intercellular adhesion molecule-1 (ICAM-1), CD40, c-Jun expression of Aortas were detected by immunohistochemistry.Result:After experiment, body weight of rats in the model group were decreased, serum total cholesterol, low density lipoprotein cholesterol, triglycerides, free fatty acids, fasting insulin, fasting blood glucose, malondialdehyde, liver coefficient, aspartate aminotransferase, alanine aminotransferase, monocyte chemotaxis protein-1, endothelin-1 levels were increased compare with the control group; high-density lipoprotein cholesterol, superoxide dismutaseactivity, insulin sensitivity index, nitric oxide synthase activity, nitric oxide, adiponectinwere decreased compared with the normal control group (P< 0.05). The weight of rats in WERI high dose group were increased, total cholesterol, low density lipoprotein cholesterol, triglycerides, free fatty acids, fasting insulin, fasting blood glucose, malondialdehyde, liver coefficient, aspartate aminotransferase, alanine aminotransferase, monocyte chemotaxis protein-1, endothelin-1 reduced on average, high density lipoprotein cholesterol, insulin sensitive index, nitric oxide synthase activity, concentration of nitric oxide, adiponectin concentration, superoxide dismutasewere increased compared with the model group (P< 0.05). Most of the liver cells in the model group were swollen and the cell line was not clear. Blob-shaped focal necrosis and inflammatory cells were found. The livers of the WERI groupsand rosiglitazone group were significantly improved, and there was no inflammatory cell infiltration. The aortic endothelial cells of the model group were proliferation, lipid was deposited, and smooth muscle cells were proliferated, distorted, arranged disorder. The number of layers was increased, the shape of the nucleus were different. Some place appeared calcificated. The aortas were significantly improved in the WERI groups and rosiglitazone group. The expression of ICAM-1, CD40 and c-Jun in aortas were also decreased compared with model group.Conclusion:(1)WERI has an effect on reducing blood glucose, regulating blood lipid, improving insulin resistance in diabetic rats. (2) WERI could protect the early liver injury in diabetic rats. (3) WERI could protect the aorta of diabetic rat, which may be related to the decrease of serum ET-1, MCP-1 level and the expression of ICAM-1, CD40 and c-Jun in aorta.