重复性“饥饿/再投喂”对高脂饮食诱导肥胖大鼠的作用及其机制研究

EFFECTS AND MECHANISMS OF REPEATED FASTING/REFEEDING ON OBESITY INDUCED BY HIGH FAT DIET IN RATS

目的探究重复性"饥饿/再投喂"饲喂方式处理对高脂饮食诱导肥胖大鼠的作用及其机制。方法设计"重复性饥饿1 d/再投喂1 d,持续6 w"的方式(基础饲料)饲喂模型动物,6 w末实验组(RFR)大鼠改为每天喂以高脂饲料(RFR-CF/HF),并将对照组随机分为两组,一组饲喂高脂饲料(HF),另一组饲喂基础饲料(CF)至第12 w。分别于实验第6 w和第12 w末处死动物,比较各组大鼠体重、Lee’s指数和脂体比的差异,检测血脂、血清中生长激素、甲状腺素、瘦素、胰岛素、血浆促肾上腺皮质激素及下丘脑匀浆神经肽Y(NPY)含量,应用RT-PCR法检测下丘脑NPY、阿片黑皮素原(POMC)mRNA的表达水平。结果 RFR-LF/HF组Lee’s指数、脂体比、血清总胆固醇、甘油三酯、低密度脂蛋白胆固醇、瘦素和胰岛素水平均显著低于HF组而高于CF组,下丘脑匀浆NPY含量和NPY mRNA表达水平显著高于HF组和CF组,POMC mRNA表达水平显著低于HF组和CF组。结论重复性"饥饿/再投喂"饲喂处理可降低高脂饮食诱导的肥胖程度,减轻外周血的瘦素抵抗和胰岛素抵抗,但可能会引起中枢神经内分泌肽表达的极度紊乱。

Objective To explore the effects and mechaniams of obesity induced by fat diet after repeated fasting/refeeding in rats.Method A model of repeating fasting/refeeding rats（repeated cycles of 1d fasting and 1d refeeding for 6 w fed with common fat diet,RFR） was designed.At the end of 6th week,the RFR rats were switched to high fat diet every day（RFR-CF/HF）.Moreover,the control rats were randomly divided into two groups and then fed with high-fat diet（HF） and common fat diet（CF） respectively for 6 w.All rats were killed at the end of 6th and 12th week,the body weight,Lee＇s index and body fat contents of rats in each group were measured.The serum lipid,growth hormone（GH）,thyroxin（T4）,leptin,insulin,plasma ACTH levels,and the concentration of hypothalamic neuropeptide Y（NPY） were measured.The expression levels of NPY and propiomelanocortin（POMC） mRNA in hypothalamus were detected by reverse transcription chain reaction（RT-PCR）.Results The Lee＇s index,body fat contents,serum TC,TG,LDL-C,leptin and insulin levels in RFR-LF/HF group were significantly lower than those in HF group,but significantly higher than those in CF group.The concentration of hypothalamic NPY and the expression level of NPY mRNA in RFR-LF/HF group were significantly higher than those in HF and CF groups,but the expression level of POMC mRNA was significantly lower than that in HF and CF groups.Conclusion The repeated fasting/refeeding pattern can decrease the obese degree induced by high fat diet,and also reduce the leptin and insulin resisitance in peripheral blood,but can cause serious expression disturbance of neuroendocrine peptides in central nervous system.