高脂膳食诱导肥胖并影响脂肪组织MCHR1和OB-Rb的表达

High fat diet induces obesity and alters the expression of MCHR1 and OB-Rb in the adipose tissue

目的:比较不同方式高脂饮食对大鼠脂肪组织黑色素聚集激素受体1(melanin concentrating hor-mone receptor 1,MCHR1)和瘦素受体(OB-Rb)表达的影响。方法:断乳大鼠分成3组:正常膳食组(NC组,13%热卡来自脂肪),与正常膳食组等热量的高脂膳食组(PHF组,47%热卡来自脂肪)及自由摄入高脂膳食组(HF组,47%热卡来自脂肪)。喂养8周后,称量大鼠体质量,检测血清中的黑色素聚集激素(melanin con-centrating hormone,MCH)和瘦素(leptin)浓度。运用实时定量PCR检测脂肪组织的MCHR1和OB-Rb mRNA水平。结果:HF组和PHF组体质量显著高于NC组(P<0.01),血清中MCH和leptin浓度较NC组有明显增高(MCH,P<0.01;leptin,P<0.05)。同对照组相比,HF组和PHF组脂肪组织中的MCHR1 mRNA水平显著升高(P<0.05),而OB-Rb mRNA却显著降低(HF组,P<0.01;PHF组,P<0.05)。HF组和PHF组的体质量、血清学指标及实时定量PCR结果差异无统计学意义(P>0.05)。结论:等热量和高热量高脂膳食都能诱导大鼠肥胖和代谢异常;高脂膳食所诱导的机体肥胖及代谢紊乱与脂肪组织中MCHR1 mRNA上调和OB-RbmRNA下调有关。

Objective To investigate the effect of high-fat （HF） diet on the body weight and the mRNA expression of melanin concentrating hormone receptor 1 （MCHR1） and leptin receptor （OB-Rb） in the adipose tissue in rats, the two important and opposite factors in regulating the body weight. Methods Post-weaning rats were divided into 3 groups： the NC group were fed a normal- chow diet （NC） （13% calories from fat）, the HF group with a HF-diet （47% calories from fat） and the PHF group pair-fed a HF-diet （47% calories from fat）. At the end of 8th week, the gained bodyweight, the plasma melanin concentrating hormone （MCH） and leptin, and the expression levels of MCHR1 and OB-Rb in the adipose tissue were measured. Results Both the HF-diet and pair-fed HF-diet enhanced the body weight （P 〈 0.01 ）, plasma MCH （P 〈 0.01 ） and leptin concentrations （P 〈 O. 05）. In the adipose tissue, HF-diet resulted in significant increase in MCHR1 （PHF group,P 〈 O. 05 ） and decrease in OB-Rb mRNA levels （HF group, P 〈 O. 01; PHF group, P 〈 O. 05）. No statistical difference was found between the HF group and the PHF group in terms of the aforementioned data （P 〉 O. 05 ）. Conclusion Chronic intake of iso-caloric HF-diet and ad libitum HF-diet obviously results in increase in the body weight, serum leptin, and MCH concentra- tion. Diet-induced obesity and related metabolic disorders are possibly correlated with up-regulated expression of MCHR1 and down-regulated expression of OB-Rb in the adipose tissue.