不同n-3/n-6多不饱和脂肪酸构成比对大鼠脂代谢和食欲的影响

目的研究不同n-3/n-6配比脂肪酸对大鼠食欲影响及其与腺苷酸活化蛋白激酶(AMPK)基因表达的关系。方法58只SD大鼠适应性喂养7天后,尾静脉取血。根据血清总胆固醇(TC)水平随机分为6组:空白组(基础饲料),高脂组(高脂饲料),高脂1∶1组(高脂饲料+n-3/n-6=1∶1油),高脂1∶5组(高脂饲料+n-3/n-6=1∶5油),低脂1∶1组(脱脂基础饲料+n-3/n-6=1∶1油),低脂1∶5组(脱脂基础饲料+n-3/n-6=1∶5油),喂养45天,观察大鼠摄食与体重增长,并于实验第0、15、30和45天测定血清总胆固醇(TC)和甘油三酯(TG)含量。于45天处死动物,取下丘脑,用RT-PCR分别测下丘脑组织中NPY、AMPK-α2 mRNA表达。结果添加PUFA的四个组血清TC、TG、摄食量、体重及NPY、AMPK-α2mRNA表达均比高脂组大鼠明显降低(P<0.05)。结论PUFA改善血脂可能是通过影响AMPK表达,从而抑制下丘脑食欲相关基因表达,进而影响血脂代谢。

Effects of dietary different ratios of n-3 to n-6 polyunsaturated fatty acids influence lipid metabolism and appetite of rats

Objective To study the effects of dietary different ratios of n-3 to n-6 polyunsaturated fatty acids on food intake of SD rats and potential mechanisms. Methods According to their serum total cholesterol level, male rats were randomly divided into 6 groups, and were fed common feed diet, high fat diet, high fat with n-3/n-6 1∶1 PUFA diet, high fat with n-3/n-6 1∶5 PUFA diet, common feed with n-3/n-6 1∶1 PUFA diet, and common feed with n-3/n-6 1∶5 PUFA diet, respectively. Weights were measured about every 6 days, and food intake were measured everyday. At 0, 15, 30 and 45 days, triglycerides (TG) and total cholesterol (TC) in the plasma were measured using kits. After 45 days, the rats were sacrificed. RT-PCR was used for measuring the expression of neuropepide Y (NPY) and AMP-activated protein kinase-α2 (AMPK-α2) mRNA in the hypothalamus. Results Four diets with any ratio of n-3/n-6 PUFA resulted in significant restraint of body weight gain, TC and TG level in the plasma, NPY and AMPK-α2 mRNA level in the hypothalamus compared to high fat diets(P<0.05). These situations in two groups with common diet and one group with high diet added 1∶1 PUFA are more significant than the high fat diet group. Conclusion These results indicate that dietary PUFA improved lipid metabolism which may be related with appetite control through AMPK path.