Study on Hypoglycemic Effect and Mechanism of Zicui Yin on Type Ⅱ Diabetic Rats / 中国药房

ABSTRACT

OBJECTIVE： To study the hypoglycemic effect and mechanism of Zicui yin on type Ⅱ diabetic rats， and to provide theoretic basis for clinical application. METHODS： Eighty male rats were fed with high fat/sugar diet for 4 weeks， and then given intraperitoneal injected with streptozotocin （35 mg/kg） to induce type 2 diabetic model. Other 10 rats were included in normal group. Model rats were randomly divided into metformin group （positive control， 0.2 g/kg）， model group （constant volume of distilled water）， Zicui yin high-dose， medium-dose， low-dose groups （14.0， 7.0， 3.5 g/kg）， with 10 rats in each group. After 2 weeks of continuous intragastic administration， the fasting blood glucose of rats in each group was measured by automatic blood glucose meter. The serum insulin level was determined by ELISA. mRNA expression of JNK， Akt and IRS-1 were detected by RT-PCR； The phosphorylation of JNK， Akt and IRS-1 proteins in the pancreatic tissue of rats in each group was detected by Western blot method. RESULTS： Compared with normal group， the fasting blood glucose， mRNA expression of JNK， The phosphorylation of JNK and IRS-1 proteins in the pancreatic tissue of the model group were significantly increased （P＜0.05 or P＜0.01）， while the serum insulin content， mRNA expression of Akt and IRS-1， the phosphorylation of Akt protein were significantly decreased （P＜0.01）. Compared with model group， the fasting blood glucose of rats in metformin group and Zicui yin high-dose and middle-dose groups decreased significantly （P＜0.05）， the serum insulin content of rats in both metformin group and Zicui yin high-dose group increased significantly （P＜0.01）， and mRNA expression of JNK in pancreatic tissue of rats in metformin group and Zicui yin groups decreased significantly （P＜0.01）， while mRNA expression of Akt and IRS-1 increased significantly （P＜0.01）. The phosphorylation of JNK and IRS-1 proteins in metformin group and Zicui yin high-dose group decreased significantly （P＜0.01）， while the phosphorylation of        Akt protein were increased significantly （P＜0.01）. CONCLUSIONS： Zicui yin can significantly reduce blood glucose level， the mechanism of which may be related to decreasing the phosphorylation of JNK and IRS-1 proteins and increasing the phosphorylation of Akt proteins in pancreatic islets.