肥胖抵抗大鼠的食欲调节

The study on mechanism of appetite regulation in diet-induced obesity resistant rats

目的 探讨肥胖抵抗大鼠摄食量减少的原因。方法 采用 50只健康雄性SD大鼠,分为对照组 10只和高脂组 40只,分别用基础饲料和高脂饲料喂养 13周,然后根据体重和能量摄入量筛选出饮食诱导肥胖抵抗(DIO-R)大鼠 9只和饮食诱导肥胖(DIO)大鼠 10只,观察总摄食量的变化,放免法测定血清瘦素和血浆神经肽Y水平,免疫印迹法测定大鼠脑组织中黑色素皮质激素受体 4(MCR- 4)蛋白含量。结果 DIO- R大鼠总摄食量为(1 679 .1±146. 8)g,明显低于DIO大鼠的总摄食量(1 818 .4±148 .9)g;DIO R大鼠血浆神经肽Y含量为 ( 795. 24±83 .59 )ng/L,显著低于DIO大鼠(1 007. 14±172. 83)ng/L;基础组大鼠血清瘦素含量为 ( 4 .80±0. 75 )μg/L,DIO R组为 ( 9 .17±1 .19)μg/L,DIO组为(9 .32±1 .04)μg/L,提示高脂饲料使大鼠血清瘦素水平明显增加,但DIO- R与DIO大鼠间无明显差别;基础组大鼠脑组织中MCR 4含量峰面积分析表明基础组为(342±31)mm2,DIO R组为(455±33)mm2,DIO组为(355±30)mm2,说明高脂饲料使DIO R大鼠脑组织中MCR- 4含量增加。结论 DIO- R大鼠通过增加ob基因的表达降低神经肽Y途径活性并激活MCR 4途径来减少进食量,从而抑制体重的增加。

Objective To explore the ca us e of decreasing intake food of diet-induced obesity resistant(DIO-R) rats. Methods Fifty male Sprague-dawley(SD) rats were randomly divided into control group and high-fat group and they were fed with basic die t and high-fat diet respectively for 13 weeks.DIO-R and diet-induced obesit y (DIO) rats were selected according to their body weight and the quantity of en ergy intake, then observing the changes of the total food intake , the level of serum leptin and plasma NPY were determined by radioimmunoassay and the contents of the melanocortin receptor-4(MCR-4)in brain were determined by Western Blot .Results The total food intake of DIO-R rats was (1 679 .1±146.8)g.The total food intake of DIO rats was (1 818.4±148.9)g .The total food intake of DIO-R rats was lower than that of DIO rats(P<0.05) .The level of plasma NPY of DIO-R rats was (795.24±83.59)ng/L.The level o f plasma NPY of DIO rats was (1 007.14±172.83) ng/L.The level of plasma NPY of DIO-R rats was lower than that of the DIO rats(P<0.05).The levels o f serum leptin of basic,DIO-R and DIO rats was (4.80±0.75) μg/L, (9.17± 1.19) μg/L and (9.32±1.04)μg/L.The level of serum leptin of rats in high -fat diet group was increased as compared with the rats in basic diet group, bu t there was no significant difference between DIO-R and DIO rats(P>0.05) .The levels of brain MCR-4 of basic,DIO-R and DIO rats were (342±31)mm ~2, (455±33)mm^2, (355±30)mm^2. High fat diets increased the content of b rain MCR-4 in DIO-R rats.Conclusion DIO-R rats descreased appetite by incre asing expression of ob gene to reduce activity of NPY pathway and activate the M CR-4 pathway, and thus inhibit the increase body of weight.