Effects Of The Roux-en-Y Gastric Bypass On Glucagon-like Peptide-1and Intestine Microbiota In Sprague-dawley Rats

BACKGROUNDPatients with type2diabetes mellitus experienced a complete and comfirm diabeticremission after RYGB．Although weight loss，reduction of food intake and other factorsmay play important roles in diabetic resolution after gastric bypass，the major mechanismis the change of gastrointestinal hormones．More and more studies have proved that themarked effects of gastric bypass is closely related to the regulatory role of the vagus nerve.We expect to demonstrate the role of vagus nerve in the resolution of T2DM followingRYGB, and illustrate its proper mechanisms from another firenew perspective.Metabolic surgery as an effective means of treating morbid obesity, weight loss and alsostudy the best model to improve obesity-related diseases. Metabolic surgery, especially thedigestive tract after RYGB important changes: reduce stomach volume, reduce gastricacid secretion, remodeling, neuroendocrine regulation of intestinal anatomy so have agreat impact on the intestinal flora. Studies have shown that the development ofhyperplasia and composition of intestinal bacteria associated with obesity, insulinresistance and metabolic disorders are closely linked.At present, human and animal models, mostly to study the ecology and activity ofintestinal microflora through feces or cecal samples. By detection of the stool sample afterRYGB, found decrease and increase of bacteria Bacteroides thick portion may be able toexplain the operation and reduce the weight and metabolic aspects of the role ofinflammation. Liou, who also confirmed this point, they will RYGB surgery group andthe sham group in the cecal flora of mice were transplanted into mice not sterile surgeryfound that transplant after RYGB group flora body weight and fat content in micedecreased by.However, for the entire study fecal gut flora as a unified whole, and does not reflectregional RYGB surgery bowel intestinal flora changes. RYGB surgery, three differentbowel microflora may be different metabolic signals are transmitted. Thus, thisexperiment, we mainly by comparing the RYGB group and the sham group biliopancreatic corresponding branch, Roux branch, joint support bacterial mRNA expression changes, tostudy the effects of surgery on the intestinal flora and to explore possible mechanisms.CHART I Effects of the hepatic branch of vagus and Roux-en-Y gastric bypass onglucagon-like peptide-1in Type2diabetic Sprague-Dawley ratsObjective To investigate the effects of the hepatic branch of vagus and Roux-en-Ygastric bypass on the level of fasting and postprandial serum glucagon-like peptide-1(GLP-1) in type2diabetic rats, and analyze their interactions.Methods In order to create the model of type2diabetes，55male SD rats wereinjected with Streptozotocin intraperitoneally. After completion,45rats were divided intofour groups: sham operation (S, n=10), sham operation within the hepatic branch of vagusto be cut off (SV, n=11), Roux-en-Y gastric bypass (RYGB, n=12), and RYGB withoutreserving the common hepatic branch (,RYGBV, n=12). Levels of fasting and postprandialserum GLP-1within50percents of glucose solution (2g/kg) after lavaging for30minwere detected before operation and postoperative at1,4,8weeks. Meanwhile, Interactionsbetween RYGB and the common hepatic branch were also calculated.Results Levels of fasting serum GLP-1didn’t show any differences before and afteroperation (P>0.05), and preoperative postprandial serum GLP-1among the four groupsalso had no significance(P>0.05). However, RYGB obviously improved postprandialGLP-1levels after1week (P<0.05), and maintained a high standard no matter after4or8weeks (P<0.05).While it slightly reduced the concentration without reserving the hepaticbranch of vagus after1week.When it comes to8weeks, cutting off or not has no effectson the level of glp-1(P>0.05). Overall, the main effect of RYGB on postprandial serumGLP-1had increased20.76pmol/L to31.96pmol/L. But, the impact of the commonhepatic branch dropped from8.05pmol/L to0.32pmol/L. No interaction was found (P>0.05).Conclusions Roux-en-Y gastric bypass surgery could obviously increasepostprandial serum concentrations of glp-1, and maintained at a relatively high level.Nevertheless, preserving hepatic branch of the vagus only appropriately increasepostprandial levels of GLP-1at an early stage, and its main effect would graduallydiminish over time. Both of them had no influences on fasting serum level of GLP-1.CHART II The mechanism and alternation of intestine microbiota after Roux-en-Ygastric bypass in normal Sprague-Dawley ratsObjective To investigate the effects and mechanisms of Roux-en-Y gastric bypasson the composition of gut microbiota among the biliopancreatic limb,the Roux limb,andthe common channel in normal SD rats.Methods Quantitative real-time PCR was used to detect totalbacteria,Bifidobacterium, Bacteroides,and Lactobacillus mRNA.Results of statisticalanalysis after Roux-en-Y gastric bypass were compared to sham-operated group.Results8weeks postoperatively, the weight difference between RYGB and shangroup was statistically significant (P <0.01).In the Roux limb, total bacteria mRNA level(RYGB,11.01±0.86vs.sham9.76±0.48), Bifidobacterium (RYGB,5.60±0.73vs.sham4.83±0.56), Bacteroides (RYGB,8.31±0.52vs.sham6.29±0.57)，and Lactobacillus(RYGB,9.90±0.36vs.sham9.53±0.18),all of the discrepancies were statisticallysignificant(P<0.05).When it comes to the common channel, total bacteria mRNA (RYGB,11.20±0.28vs.sham9.71±0.42), Bifidobacterium (RYGB,5.61±0.67vs.sham4.05±0.23),Bacteroides (RYGB,7.36±0.40vs.sham6.83±0.26)，all of the differences were statisticallysignificant(P<0.05) except the Lactobacillus(RYGB,9.21±0.39vs.sham 9.48±0.33,P>0.05).While in the biliopancreatic limb,there were no differences betweenRYGB and sham group in all of the statistics(P>0.05).Conclusion Roux-en-Y gastric bypass surgery can significantly improve the totalbacteria, bifidobacterium,and bacteroides mRNA expression levels in Roux and commonbranch, while have no influences on biliopancreatic limb.Conclusion of the overall study Roux-en-Y gastric bypass surgery couldobviously increase postprandial serum concentrations of glp-1, and maintained at arelatively high level. Nevertheless, preserving hepatic branch of the vagus onlyappropriately increase postprandial levels of GLP-1at an early stage, and its main effectwould gradually diminish over time. Both of them had no influences on fasting serum levelof GLP-1. Roux-en-Y gastric bypass surgery can significantly improve the total bacteria,bifidobacterium,and bacteroides mRNA expression levels in Roux and common branch,while have no influences on biliopancreatic limb.