营养性肥胖大鼠的脂代谢紊乱与下丘脑中增食欲素A的表达分析

Hypothalamic expression of orexin A and lipid metabolism disorder in rats with alimentary obesity

目的:研究营养性肥胖大鼠下丘脑中增食欲素(orexin A)表达与脂代谢紊乱的规律。方法:高脂饮食诱导并评估营养性肥胖大鼠动物模型;采用化学发光免疫分析法和生化酶法测定大鼠血清胰岛素(Ins)、甘油三酯(TG)和总胆固醇(TC);应用实时定量PCR检测下丘脑组织中orexin A mRNA的表达规律。结果:大鼠高脂膳食饲养8周后,营养性肥胖大鼠的体重、体脂含量和Lee′s指数均高于对照组,血清Ins增加约50%,TG和TC分别增加约94%和43%(P<0.05);营养性肥胖大鼠下丘脑中orexin A的mRNA表达减少约57%(P<0.05),且orexin A的表达量与Lee′s指数、Ins、TG、TC呈显著负相关,相关系数分别为r=-0.798(P<0.05)、r=-0.868(P<0.05)、r=-0.981(P<0.05)和r=-0.815(P<0.05)。结论:在大鼠高脂膳食诱导的营养性肥胖过程中,下丘脑orexin A的低表达和脂代谢紊乱均与营养性肥胖的发生密切相关。

AIM： To evaluate the effect of orexin A in rat hypothalamus on lipid metabolism disorder in rats with alimentary obesity induced by high-fat diet.METHODS： The rat model of alimentary obesity was induced by high-fat diet.The levels of insulin,triglyceride（TG） and total cholesterol（TC） in the serum were detected by luminescent immunoassay and enzymic method.The mRNA expression of orexin A in rat hypothalamus was determined by real-time PCR.RESULTS： There were statistically significant differences of weight,body fat content,and Lee′s index between high-fat diet group and control group after 8-week feeding of high-fat diet.Compared to control animals,the levels of insulin,TG and TC in the rats with alimentary obesity significantly increased by 50%,94% and 43%,respectively（P0.05）.The expression of orexin A in rat hypothalamus significantly decreased by 57%,and had significant negative correlation with Lee′s index,insulin,TG and TC.Their correlation coefficients were r=-0.798（P0.05）,r=-0.868（P0.05）,r=-0.981（P0.05） and r=-0.815（P0.05）,respectively.CONCLUSION： Alimentary obesity and lipid metabolism disorder induced by high-fat diet are correlated with down-regulation of orexin A expression in rat hypothalamus.