减重手术调控胃饥饿素对肥胖大鼠摄食量和体质量的影响

Effects of bariatric surgery on food intake and body weight of obese rats regulated by Ghrelin

目的:探究减重手术调控胃饥饿素(Ghrelin)从而对肥胖大鼠摄食量和体质量的影响。方法:将90只雄性5周龄SD大鼠随机分为普通饲料喂养组(15只)和高脂饲料喂养组(75只),自由摄食水,经过5周高脂饲料喂养,高脂饲料组中体质量高于普通饲料组20%以上的大鼠视为肥胖模型构建成功。将高脂饲料组大鼠随机分为肥胖模型组、假手术组、减重手术组,15只/组,造模期间记录大鼠体质量(1次/周)和每日摄食量。减重手术组采用袖状胃切除术,术后记录各组大鼠1-4周体质量和摄食量的变化,第4周腹主动脉取血检测血清三酰甘油(TG)和总胆固醇(TC)含量,WB检测胃组织Ghrelin、mTOR、p-mTOR、p70s6k、p-p70s6k蛋白表达情况。结果:与肥胖模型组相比,减重手术组的肥胖大鼠摄食量和体质量下降(P<0.05);减重术后第4周减重手术组大鼠血清三酰甘油和总胆固醇含量低于假手术组与肥胖模型组(P<0.05);与肥胖模型组相比,减重手术组大鼠胃组织中p-mTOR、p-p70s6k和Ghrelin的蛋白表达降低(P<0.05)。结论:减重手术可能通过抑制mTOR/p70s6k通路,下调促进摄食的Ghrelin表达,减少肥胖大鼠摄食量,降低体质量。

Objective:To investigate the effects of bariatric surgery on food intake and body weight in obese rats by regulating Ghrelin.Methods:Ninety male 5-week-old SD rats were randomly divided into normal diet feeding group(n=15)and high fat diet feeding group(n=75).After 5 weeks of high fat diet feeding,the rats in the high fat diet group whose body weight was 20%higher than that in the normal diet group were considered as successful obesity models.The rats in high-fat diet group were randomly divided into obesity model group,sham operation group and bariatric operation group,with 15 rats in each group.The body weight(once a week)and daily food intake of rats were recorded during the modeling period.The sleeve gastrectomy was performed in the bariatric operation group,and the changes of body mass and food intake in each group were recorded after 1-4 weeks.At the 4th week,blood samples from abdominal aorta were collected to detect the contents of triglyceride(TG)and total cholesterol(TC)in serum,and the protein expression of Ghrelin,mTOR,p-mTOR,p70s6k and p-p70s6k in gastric tissue was detected by WB.Results:Compared with the obesity model group and the sham operation group,the food intake and body weight of obese rats in the bariatric operation group were decreased(P<0.05).The contents of serum triglyceride and total cholesterol in bariatric surgery group were higher than those in sham operation group and obesity model group at the 4th week after bariatric surgery(P<0.05).Compared with the obesity model group,the protein expressions of p-mTOR,p-P70S6K and Ghrelin in the gastric tissue of the bariatric surgery group were significantly decreased(P<0.05).Conclusion:Bariatric surgery may reduce food intake and body weight in obese rats by inhibiting mTOR/P70S6K pathway and down-regulating the expression of Ghrelin that promotes food intake.