Effect of gastric bypass surgery on fasting blood glucose and pancreatic islet cell in type 2 diabetic rats / 中华内分泌外科杂志

ABSTRACT

Objective To study the effect and mechanism of gastric bypass surgery on type 2 diabetic rats.Methods The models of type 2 diabetic rats were induced by stretozotocin and 20 diabetic rats were randomly divided into 2 groupsdiabetes-operation group (DO group,n =10)and diabetes-control group(DC group,n =10).20 normal rats were randomly divided into 2 groupsnormal-operation(NO group,n =10) and normalcontrol group(NC group,n =10).Rats in DO and NO group underwent GBP and rats in DC group and NC group underwent sham operation.Fasting blood glucose(FBG) levels of rats in each group were detected before operation and on 72 h,1th week,4th week,8th week after operation.On the 8th week after operation,pancreas tissues were harvested for HE staining and immunofluorescence,histological changes observed.Results The FBG levels of rats were not statistically significant different before operation between DO group and DC group or between NO group and NC group (P ＞ 0.05).After operation,the FBG levels of rats in DO group gradually declined (P ＜ 0.05).FBG levels of rats in DO group were lower after operation than before operation(P ＜0.05) ; After operation FBG levels of rats were higher in DO group than in NO group and NC group at the same time point (P ＜0.05).In DC group,the difference of FBG levels of rats at different time point was not statistically significant(P ＞ 0.05).The difference of FBG had no statistically significance between the different time points of the same group or between the same time point of different groups (P ＞ 0.05).HE staining showed that,in DO group,newborn small islets appeared in pancreas which increased the number of islet.The new islets were smaller,mostly around the pancreatic duct and the structure was similar to that of the normal islets.Immunofluorescence staining also showed that the number of islets increased.Insulin immunofluorescence found more isolated small islets composed of two or three insulin positive cells.Insulin and glucagon double immunofluorescence found insulin and glucagon double positive(INS +/GLU +)cells in some islets.Conclusions GBP has obvious hypoglycemic effects on FBG levels of type 2 diabetic rats,in which the regeneration of pancreas islets may play an important role,while on normal rats GBP has no hypoglycemic effects.