大米蛋白对幼鼠血脂及脂质代谢调控因子基因表达水平的影响

为了探讨大米蛋白对生长期幼鼠血脂水平及脂质代谢相关因子的调控作用,分别给雄性Wistar 7周龄幼鼠饲喂添加1%胆固醇及0.25%胆酸钠的大米蛋白及酪蛋白(粗蛋白含量为20%),自由摄食3周后,测定实验鼠血浆总胆固醇、血浆高密度脂蛋白胆固醇、血浆三酰甘油水平及肝脏3-羟基-3甲基-戊二酰CoA还原酶(HMG-CoA R)、乙酰辅酶A乙酰基转移酶2(ACAT2)、固醇调节元件结合蛋白-1(SREBP-1)的基因表达水平。对照酪蛋白,大米蛋白显著降低幼鼠血浆总胆固醇、血浆非高密度脂蛋白胆固醇、血浆三酰甘油水平,并且显著降低了肝脏HMG-CoA R、ACAT2、SREBP-1的基因表达水平。实验结果表明,大米蛋白具有降低幼鼠血脂水平的功效,其主要作用机制之一是抑制其脂质合成与吸收。

Rice Protein Affects Plasma Lipids Level and Gene Expression of Lipid Metabolism-related Factors in Growing Rats

To elucidate the effects of rice protein on plasma lipids level and gene expression of lipid metabolism-related factors in growing rats,male Wistar 7-week-old rats were fed cholesterol-enriched diets(1% cholesterol and 0.25% sodium cholate) with 20%(as crude protein) of rice protein and casein ad libitum for 3 weeks.Plasma levels of total cholesterol(TC),high-density lipoprotein cholesterol(HDL-C),triglyceride(TG) and hepatic gene expression of 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMG-CoA R),Acyl CoA:cholesterol acyltransferase 2(ACAT2),sterol regulatory element binding protein-1(SREBP-1) were measured.Rice protein produced marked hypolipidemic action in comparison to casein,reflecting in the significant reduction of TC,non high density lipoprotein cholesterol(non HDL-C) and TG in plasma(P< 0.05),whereas there was no significant difference of plasma HDL concentration between casein and rice protein.To support,hepatic gene expression of HMG-CoA R,ACAT2 and SREBP-1 were significantly decreased in growing rats fed rice protein as compared with casein(P< 0.05).The present results suggest that the inhibition of lipid synthesis and absorption is one of major hypocholesterolemic mechanisms exerted by rice protein.