| Objective:The effects of intestinal bypass with different length on body weight,food intake,fasting plasma glucose(FPG),glucagon like peptide-1(GLP-1),branched chain amino acid(Leu,Val,Ile)and aromatic amino acid(Tyr,Phe)in type 2 diabetic rats were studied to clarify the probably reason of therapeutic effect of intestinal bypass on type 2diabetes.Methods: Thirty two GK(goto Kakizaki)rats were randomly divided into four groups(n =8).After the pylorus was cut off,the rats in group A were anastomosised again.The rats in group B were anastomosed after bypassing the duodenum.The rats in group C were anastomosed after bypassing the duodenum and jejunum.The rats in group D were anastomosed after bypassing the duodenum,jejunum and part of ileum.The rats' body weight and food intake were measured before operation,one week after operation,three weeks after operation,six weeks after operation and twelve weeks after operation.The fasting blood glucose(FPG),insulin(fins)and HOMA-IR were measured by biochemical method,The contents of BCAAs in serum of rats were determined by HPLC and the changes were calculated according to the statistical principle.Results:(1)The total survival rate of 32 rats in four groups was 62.5%.One rat died one day after jejunal bypass.Two rats in ileal bypass group died 3 days after operation.Rats in ileal bypass group died of severe malnutrition,diarrhea and other metabolic complications 3to 4 weeks after operation.(2)Compared with the weight before operation,the weight of GK rats in the sham operation group,duodenal bypass group and jejunal bypass group increased slightly in the first week,and significantly in the third,sixth and twelfth weeks(P < 0.05).There was no significant difference between the two groups at the 12 th week(P > 0.05).The ileal bypass group continued to lose weight for 1-3 weeks,while the other three groups gained weight over time.The food intake of rats in the GBP operation group(duodenal bypass group,jejunal bypass group and ileal bypass group)decreased within one week after operation and reversed after one week,but the food intake level of rats in the GBP operation group was always lower than that of rats in the sham operation group(P < 0.05).(3)There was significant difference in GLP-1 between the GBP group and the sham operation group at each time point from 1 to 12 weeks after operation(P < 0.05).At 12 weeks after operation,the GLP1 value of the rats in the GBP group was significantly higher than that in the sham operation group(P < 0.05),and increased with the increase of the length of the small intestine bypass section,especially in the jejunum bypass group.(4)During 1 to 12 weeks after operation,the fasting blood glucose in the GBP group was significantly lower than that in the sham operation group,especially in the jejunal bypass group(P < 0.05).There was no significant difference in FPG,fins and HOMA-IR between duodenal bypass group and jejunal bypass group(P > 0.05).(5)A significant difference could be observed in GLP-1between the GBP group and the sham operation group at each time point from 1 to 12 weeks after operation(P < 0.05).At 12 th week after operation,the GLP-1 value of the rats in the GBP group was significantly higher than that in the sham operation group,especially in the jejunal bypass group(P < 0.05).And there was a significant difference in GLP-1 value between the duodenal bypass group and jejunal bypass group(P < 0.05).(6)There was no significant difference in BCAAs(leucine,isoleucine,valine)between the four groups(P >0.05).During 1 to 12 weeks after operation,there were significant differences in BCAA between the two groups(P < 0.05).With the passage of time,the decrease of three kinds of BCAAs in the GBP group was more and more obvious,especially in the jejunal bypass group(P < 0.05).The levels of leucine,isoleucine and valine in jejunal bypass group were significantly lower than those in duodenal bypass group in 12 weeks after operation.Conclusion: The improvement of blood glucose and HOMA-IR in type 2 diabetic rats after GBP operation is likely to be independent of body weight.Duodenal and proximal jejunal bypass is the best treatment,while excessive intestinal bypass may affect the absorption function of rats,leading to malnutrition or even death.The secretion of GLP-1increased with the length of small intestinal bypass.Different segments of small intestinal bypass can reduce branched amino acids to different degrees,and the extent of reduction is proportional to the length of the bypass.The mechanism may be related to the improvement of insulin resistance. |
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