| Objective:To verify feasibility of gastric bypass surgery for non obese type 2 diabetic rats(GK rats)and to complete gastric bypass surgery for GK rats,using normal rats(wistar rats)to establish stomach-preserving gastrointestinal bypass surgery(GBP)animal model.By analyzing the changes of body weight,fasting blood glucose level and islet function in three groups of GK rats before and after operation,investigate therapeutic effect of gastric bypass surgery on GK rats and effect of insulin resistance.Methods:Part of preliminary experiment: 30 male wistar rats in similar age and weight were randomly divided into two groups,each group has fifteen rats.Group 1: control group,the sham group,mutilated pylorus then anastomosed;Group 2: operated group,GBP group,retaining full stomach and duodenum plus jejunum excluded.The surgery time and rate of operative success of two groups was recorded,postoperative complications were observed and death causes of the rats were analyzed.Part of formal experiment: 30 male GK rats in similar age and weight were randomly divided into three groups,each group has ten rats.Group 1: the sham group,mutilated pylorus then anastomosed;Group 2: operated group,GBP group,retaining full stomach and duodenum plus jejunum excluded;Group 3: blank group,without operation.The tail vein blood of rats was respectively gotten before operation and postoperative 1,3,6,12 weeks.Body mass and fasting plasma glucose(FPG)levels in three groups of GK rats were measured by electronic balance and blood glucose meter.Enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of fasting insulin(FINS)and glucagon like peptide-1(GLP-1)before and after operation.Finally insulin resistance index(HOMA-IR)was calculated.Results:Part of preliminary experiment: The total survival rate of the two groups of rats was 66.67%.For the sham group,the average operative time was 75.93±13.58 min,6 rats died during and after operation.The mean operative time in GBP group was 103.6±11.52 min,4 rats died intraoperative and postoperative.Part of formal experiment: The overall survival rate was 93.33%,which one rat died on the 7th day after operation in sham group and one died on the 5th day after operation in GBP group.Compared with the preoperative,the body weight of all operated rats decreased during first week,then the body mass of rats in each group significantly increased during 3rd,6th and 12 th weeks after operation,the difference was statistically significant(P <0.05).Compared with the preoperative and the bland group and the sham group at the same time point,FPG of the GBP group decreased,and the number decreased from 14.67±1.73mmol/L to 5.05±0.42mmol/L after the operation for 12 th weeks,the difference was statistically significant(P <0.05).Compared with the preoperative and the bland group and the sham group at the same time point,FINS in the GBP group after surgery experienced a process of first rising and then falling.During 1 to 3 weeks after operation FINS rose,at six weeks began to decline slightly,to 12 weeks significantly decreased from 14.74±1.01 m U/L to 8.48±1.01 m U/L,the difference was statistically significant(P <O.05).Compared with the preoperative and the bland group and the sham group at the same time point,HOMA-IR of GBP group continued to decline,which decreased from 9.59±1.15 to 1.91±0.34,the difference was statistically significant(P <O.05).Compared with the preoperative and the bland group and the sham group at the same time point,GLP-1 levels of GBP group increased from 9.18±0.78pmol/L to 27.66±0.95pmol/L after operation,the difference was statistically significant(P <O.05).Conclusion:1?It is feasible to carry out the stomach-preserving gastrointestinal bypass surgery in rats,and the operation model of non obese GK rats is successfully established.2?There is remarkably therapeutic effect of the stomach-preserving gastrointestinal bypass surgery for the treatment of non obese GK rats,which can significantly reduce fasting blood glucose and improve glucose metabolism,and with the change of body mass of rats has nothing to do.3?Food advanced into the ileum after gastric bypass surgery stimulates the secretion of GLP-1,to achieve the therapeutic effect of gastric bypass on type 2 diabetes. |
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