Selective Therapeutic Effect of Cornus officinalis Fruits on the Damage of Different Organs in STZ-Induced Diabetic Rats

The aim of the present study was to identify the selective therapeutic effects of Corni Fructus (Cornus officinalis Sieb. et Zucc.) on different organs in streptozotocin (STZ)-induced diabetic rats. Diabetes in rats was induced by intraperitonal injection with STZ at a dose of 30 mg/kg body weight (bw) for 3 days (once per a day). STZ-induced diabetic rats were orally administrated Corni Fructus (CF) extract at 300 mg/kg or metformin at 250 mg/kg daily for 4 weeks. Blood glucose and triglyceride (TG) in sera and urine total volume were measured. Histopathological changes of different organs, pancreas, liver, kidney, and lung tissues were observed by H&E staining. The expression of insulin and alpha-smooth muscle actin (alpha-SMA) was investigated in pancreas, and kidney by immunohistochemistry, respectively. The results revealed that CF extract significantly decreased the serum levels of blood glucose, and TG, and also urine total volume in STZ-induced diabetic rats. The histological examinations revealed amelioration of diabetes-induced pancreas injury including pathological changes of the Langerhans's islet and glomerular with their loss after the administration of CF extraction. Moreover, the administration of CF extract increased the numbers of insulin releasing beta cells in pancreas and also inhibited the expression of alpha-SMA in kidney of STZ-induced diabetic rats. On the other hand, CF extract showed no effect on the pathological damages of liver and lung in STZ-induced diabetic rats. These results demonstrated that CF extract may have a selective therapeutic potential through the control of hyperglycemia, and the protection of pancreas and kidney against diabetic damage.