The Influcece of Catalpol on the Expression of Insulin in Islet Cells of Diabetic Rats

Zou Guoliang; Zhong Weili; Shi Chengkun; Xu Rui; Zhao Shuang; Liu Li

doi:10.12102/j.issn.1672-1349.2018.07.009

Abstract：Objective To study the effect of Catalpol on the expression of insulin in islet cells of diabetic rats.Methods Eight-week-old male wistar rats were randomly divided into the blank group (n =10) and the experimental group (n =90).The rats in experimental group were fed with high fat and high sugar diet for 8 weeks,after intraperitoneal injection of streptozotocin (STZ,15 mg/kg),with fasting blood glucose≥16.7 mmol/L as type 2 diabetes model standard.Sixty diabetic rats were randomly divided into model group,metformin group,catalpol low-,middle-and high-dose group.The rats in blank group and model group were fed with distilled water 5 mg/(kg · d).The rats in metformin group was given metformin 90 mg/(kg · d).The rats in catalpol low-,middle-and high-dose group were fed catalpol 2.5 mg/(kg · d),5 mg/(kg · d),10 mg/(kg · d).After 12 weeks,the expression levels of insulin on islet cells were meas ured by immunohistochemistry.AMP activated protein kinase (AMPK)-α1 protein expression was detected by western blot.Results Immunohistochemical staining showed that insulin was expressed on islet cells in all groups.Compared with the model group,the expression of insulin on islet cells in metformin group and catalpol low-,middle-and high-dose group were relatively higher.There was difference in the expression of insulin between metformin group and catalpol middle-dose group or high-dose group (P ＜0.05).Western blot results showed that compared with the model group,the expression of AMPK-α1 protein in the islet cells were relatively increased in metformin group,catalpol low-,middle-and high-dose group (P ＜0.05).The expression of AMPK-α1 protein in catal pol high-dose group was higher than that in in metformin group,catalpol low-,middle-dose group (P ＜0.05).Conclusion Catalpol can protect the islet cells and promote the secretion of insulin,which may be the mechanism through up-regulating AMPK-α1 protein expression in diabetic rats.