运动和限食减肥对肥胖大鼠血浆和胃组织ghrelin表达的影响

The Effects of Exercise- and Food Intake Restriction-induced Weight Loss on the Expression of Ghrelin in Plasma and Stomach of Obese Rats

目的:观察运动和限食减肥对肥胖大鼠血浆和胃组织ghrelin表达的影响,初步探讨ghrelin在减肥中的作用。方法:100只雄性断乳SD大鼠按照体重随机分为对照组(普通饲料喂养,n=20)和模型组(高脂饲料加普通饲料混合喂养,n=80),以普通饲料组Lee’s指数正常值上限+tv,a.s为肥胖确定标准,高于此标准为肥胖。营养性肥胖SD雄性大鼠随机分为肥胖对照组、游泳减肥组、限食减肥组、游泳+限食减肥组,同时选取普通饲料组大鼠8只作为对照。游泳减肥组每天游泳40min,每周游泳6天,持续5周。限食减肥组计算减肥开始前2周动物平均每日进食量减量1/3,喂养3周后,再减量1/3,并再持续2周。游泳+限食减肥组游泳条件与单纯游泳减肥组一致,限食条件与限食减肥组一致。实验5周后取材,测定睾周和肾周脂肪量、血浆和胃组织ghrelin蛋白以及胃组织ghrelin mRNA表达量。结果:肥胖对照组胃ghrelin蛋白和mRNA表达均明显低于正常对照组(P<0.05),但血浆ghrelin下降不明显(P>0.05)。与肥胖对照组相比,减肥组大鼠体重和内脏脂肪含量明显下降,游泳减肥组及游泳+限食减肥组血浆和胃ghrelin蛋白和mRNA表达均升高(P<0.05),限食减肥组胃ghrelin mRNA表达增高(P<0.05),血浆和胃ghrelin蛋白变化不明显。结论:运动减肥过程中伴随着体重下降出现ghrelin水平回升,而限食减肥过程中,ghrelin的变化不太明显,因此,ghrelin可能主要参与运动减肥的过程。

Objective To clarify the effects of exercise-and food intake restriction-induced weight reduction on expression of ghrelin in plasma and stomach of obese rats,and to explore the role of ghrelin during weight loss.Methods 100 weaned Sprague-Dawley（SD）rats were randomly divided into control group（fed with standard chow,n= 20） and model group（two-bottle-feeding methodf,ed with standard chow and high-fat diet simultaneously,n=80）.After 20 weeks feeding,Lees’ index of control was used as the reference of diet-induced obesity identification,and then diet-induced obese rats were randomly divided into four groups：obese control groups,wimming groupf,ood intake restriction group and swimming＋food intake restriction group,eight rats in each group.Rats in swimming group underwent long-term（40 min,6 days/week for 5 weeks）swimming exercise.Calorie in food intake restriction group was restricted 1/3 of normal kcal for 3 weeksa,nd subsequently restricted 1/3 for 2 weeks.Swimming＋food restriction group had the same intervention as swimming and food restriction group.8 normal diet rats were also chosen as controls.After five weeks of treatments,peripheral fat mass of testis and kidney,ghrelin proteins in plasma and stomach,and ghrelin mRNA in stomach were measured.Results Gastric ghrelin protein and mRNA were significantly lower in obese control group than those in normal control group（P 〈0.05）.However,plasma ghrelin did not decrease markedly in obese control rats（P 〉0.05）.Compared with obese control group,weight and fat mass in all weight loss groups declined notablely（P〈 0.05）;in swimming and swimming＋food restriction groupst,he expression of ghrelin protein or mRNA in plasma or stomach increased remarkably（P〈 0.05）i;n food restriction groupt,he level of ghrelin mRNA raised significantly（P〈 0.05）,while ghrelin protein in plasma and stomach had not change.Conclusion The level of ghrelin increased in exercise induced weight loss,while showed no significant change in food intake restriction groups,uggested that ghrelin might be involved in the process of weight loss induced by exercise.