The Changes Of Amylin Expression And Apoptosis Of Pancreatic Islets And Influence Of Metformin And Rosiglitazone On Amylin Expression And Apoptosis In IR Rats

Objective: 1 )To evaluate dynamically the expression of amylin in pancreatic islets and apoptotic levels in pancreatic islets of insulin resistance rat models. 2) To investigate the effects of metformin and rosiglitazone on function and apoptosis of pancreatic β cells . Methods: 1) IR rat model was established with high-fat diet. And control rats were fed with normal chow(control guoup). Setting 5 stages as 10,14,16,18,20 week during evolution of IR. 2) Normal wistar rats were divided into four groups before or after IR rat model establishment. They were normal chow group(NC),high-fat diet (HF),metformin-treated (HF+Met), rosiglitazone-treated(HF+Ros).Amylin was examined by immunohistochemistry and amyloid by congo red in pancreatic islets, at the same time ,apoptotic level were evaluated by TUNEL. Ultrastructure of β cells was observed with transmission electron microscope in rats with metformin or rosiglitazone.Results:(1) The expression of amylin was higher since the tenth week in pancreatic islets of fat-fed rats compared with normal rats, and apoptotic level was also increased at the 10th week .(2)Amylin expression was positively correlated with apoptotic level in pancreatic β cells. (3)Comparing wth the fat-fed rat models, the level of amylin and apoptosis was lowered in the metformin and rosiglitazone groups .