饮食对下丘脑神经肽Y基因表达及肥胖影响

Effects of dietary on hypothalamic neuropeptide Y gene expression and obesity in rats

目的探讨高脂饮食对大鼠神经肽Y(NPY)基因表达及分泌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实验组和基础对照组,分别给予高脂饲料和基础饲料喂养13周。据13周末体重从高脂饲料组选出体重最重和体重最轻者各9只为饮食诱导肥胖(DIO)和饮食诱导肥胖抵抗(DIR)组,比较各组大鼠能量摄入水平、血浆和下丘脑匀浆NPY及下丘脑NPY mRNA表达的差异。结果DIO组大鼠能量摄入量、下丘脑和血浆NPY水平之比显著高于DIR组和对照组(P<0.01),DIO组大鼠下丘脑NPY mRNA表达显著高于DIR及对照组,而上述各指标DIR与对照组间差异均无统计学意义(P>0.05)。结论高脂饮食喂养条件下,SD大鼠表现为明显的肥胖易感性差异,这种差异与大鼠的能量摄入水平有关,下丘脑NPY高水平表达和分泌可能是导致肥胖易感大鼠多食和热能摄入过多的内在机制之一。

Objective To explore the effect of high-fat diet on the hypothalamic neuropeptide Y（NPY）expression and the mechanisms which predispose some individuals to become obese on high-fat diet. Methods Thirty-six female SD rats were randomly divided into high-fat diet group（ n = 27）and chow fed control group（ n= 9）. After 13 weeks of either a highfat diet or chew fed diet, the high-fat diet group was subdivided into Dietary Induced Obesity（DIO）and Dietary Induced Obesity Resistant（DIR）group according to the final body weight. Weight gain, food intake, and the concentration of plasma and hypothalamus neuropeptide Y were measured, and hypothalamic NPY mRNA expression were determined by RT-PCR. Resuits The levels of body weight, caloric intake, and the ratio of plasma and hypothalamus NPY were significantly higher in DIO group than in DIR or control group（ P〈 0.01 ）, while no significant difference was found between DIR and control group （ P 〉 0.05） ; hypothalamic NPY mRNA were increased in DIO group but not in DIR than control group. Conclusion On the High-fat diet, SD rats showed different susceptibility to obese and overeating, increased hypothalamic NPY were associated with their predispose to obese and overeating.