Effects of Losartan on the Expression of Transforming Growth Factor Beta 1 and Smad7 Protein in the Pancreatic Tissue of Diabetic Rats

Objective To study the effects of angiotensin II(Ang II) receptor blocker losartan on the expression of transforming growth factor beta 1(TGF-β1) and Smad7 protein in the pancreatic tissue of diabetic rats. Methods 90 healthy adult Wistar rats were selected as the object of observation of this experiment, and they were randomly divided into healthy group, diabetic group and diabetes losartan group with 30 rats in each. The healthy group was treated with normal feed, the diabetic group and diabetes losartan group were treated with the high fat and calorie feed. 8 weeks after feeding, the diabetic group and diabetes losartan group were injected with streptozotocin(STZ) for induction of diabetic rats model. After the success of modeling, the rats in the diabetes losartan group were given intragastric administration of losartan 30 mg/kg/d. And 8 weeks later, the changes in body weight, blood glucose, blood insulin and expression of TGF-β1 and Smad7 protein were compared between the groups. Results(1) The blood glucose of the diabetic group and the diabetes losartan group was(19.3±2.7) mmol/L,(13.1±1.6) mmol/L, respectively, significantly higher than that of the healthy group, respectively, while the blood insulin and body weight were lower than those of the healthy group, P0.05.(2) The TGF-beta 1 content in the diabetic control group and the diabetes losartan group was(0.41 ±0.11) mmol/L,(0.15 ±0.09) mmol/L, respectively, all increased; Smad7 protein content was(0.23 ±0.08) and(0.36 ±0.11), respectively, all decreased, the indicators in the diabetes losartan group improved significantly, better than the diabetic control group with statistical significance, P0.05. Conclusion Ang II receptor blocker losartan can reduce the expression of TGF-beta 1 protein in pancreatic tissue, decrease the excretion of TGF-beta 1 and Smad7 protein in the urine, inhibit the fibrosis of pancreatic islet tissue of diabetic rats, thus it can protect the kidney.