高脂膳食诱导肥胖并影响脂肪组织MCHRI和OB-Rb的表达

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 hormon ereceptor1，MCHRl）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 concentrating hormone，MCH）和瘦素（1eptin）浓度。运用实时定量PCR检测脂肪组织的MCHRl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MCHRlmRNA水平显著升高（P〈0．05），而OB-RbmRNA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MCHRlmRNA上调和OB-RbmRNA下调有关。

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

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.