肥胖和肥胖抵抗大鼠神经肽Y及其受体基因表达的研究

目的:探讨高脂饲料对大鼠下丘脑神经肽Y(NPY)及其受体Y1、Y2、Y5基因表达的影响及大鼠肥胖易感性差异的机制。方法:36只雌性SD大鼠,按体重随机分为高脂组和对照组,分别给予高脂饲料和基础饲料13w。实验结束时,根据体重将高脂组分为饮食诱导肥胖(DIO)和肥胖抵抗(DIO-R)大鼠,观察各组大鼠体重、内脏脂肪湿重、脂体比、热能摄入量及能量利用率的差异;RT-PCR法测定下丘脑NPY及其受体Y1、Y2、Y5mRNA的表达水平。结果:DIO大鼠体重、内脏脂肪湿重、脂体比、热能摄入量及能量利用率显著高于对照组和DIO-R大鼠,而DIO-R大鼠与对照组相比未见显著性差异;DIO大鼠下丘脑NPY及其受体Y1、Y2、Y5mRNA的表达水平显著高于对照组和DIO-R大鼠,而DIO-R大鼠与对照组相比,除Y2受体mRNA的表达水平显著下降外,其余指标均无显著性差异。结论:高脂饲料诱导下,SD大鼠表现为明显的肥胖易感性差异,下丘脑NPY及其受体的高水平表达可能是导致DIO大鼠热能摄入过多的内在机制之一。

HYPOTHALAMIC NEUROPEPTIDE Y AND ITS RECEPTORS mRNA EXPRESSION IN DIET-INDUCED OBESE AND RESISTANT RATS

Objective: To investigate the effect of high-fat diet on expression of hypothalamic neuropeptide Y (NPY) and Y1, Y2, Y5 receptor in rats and the mechanism related to the susceptibility of obesity. Method:Thirty-six female SD rats were randomly divided into high-fat diet group (n=27) and control group (n=9), and fed for 13 w. Then the high-fat diet group was subdivided into dietary induced obese (DIO) and dietary induced obese resistant (DIO-R) group according to the final body weight. Body weight, visceral fat accumulation, caloric intake, energy efficiency were measured. RT-PCR was used to measure the expression of NPY, and Y1, Y2, Y5 receptor mRNA in hypothalamus. Results: Body weight, visceral fat accumulation, body fat percent, caloric intake, energy efficiency, and the expression of NPY and Y1, Y2, Y5 receptor of DIO group were higher significantly than those of control and DIO-R group, while no significant difference between DIO-R and control group, except that Y2 receptor was decreased in DIO-R group.Conclusion: The rats fed high-fat diet increased hypothalamic NPY and Y1, Y2, Y5 receptor expressions which were closely associated with predisposition to obese and overeating of DIO rats.