浓缩鱼油升高大鼠血清高密度脂蛋白胆固醇机理的探讨

INVESTIGATION OF THE MECHANISMS OF INCREASE INSERUM HIGH DENSITY LIPOPROTEIN CHOLESTEROLBY CONCENTRATED FISH OIL IN RATS

本文从酶学方面探讨了富含廿碳五烯酸甲酯(EPA-M)和廿二碳六烯酸甲酯(DHA-M)浓缩鱼油升高大鼠血清高密度脂蛋白胆固醇(HDL-C)的机理。实验分三组(高脂组、高脂+橄榄油组和高脂+鱼油组)。后两组动物分别以灌胃法给予橄榄油与浓缩鱼油,每头0.5ml/d,高脂组不喂其它油脂,实验期6周。结果显示,鱼油组大鼠血清HDL-C水平显著高于高脂组和橄榄油组(P<0.01),H-DL-C的变化是由于高密度脂蛋白亚属Ⅱ胆固醇(HDL_2-C)水平升高,而高密度脂蛋白亚属薑胆固醇(HDL_3-C)水平无显著改变。鱼油组大鼠血清卵磷脂胆固醇酰基转移酶(LCAT)及肝素化后血浆脂蛋白脂酶(LPL)活性显著高于高脂组和橄榄油组(P<0.01),肝素化后血浆肝内皮细胞脂酶(HEL)活性显著低于其它两个对照组(P<0.05)。以上结果表明,浓缩鱼油可能通过激活LCAT和LPL活性促使HDL生成增加;同时抑制HEL活性,减少HDL的分解,从而传大鼠血清HDL-C水平升高。

In this experiment, we investigated with enzymological methods the mechanisms of increase in serum high density lipoprotein cholesterol (HDL-C) in rats fed with concentrated fish oil. The rats were fed with high fat diet (Group 1), high fat plus olive oil (Group 2) and high fat plus concentrated fish oil (Group 3) for 6 weeks respectively. The concentrated fish oil contained about 26% methyl-eicosapentaenoate (EPA-M) and 52% me-thyl-docosahexaenoate (DHA-M), and was given in 0.5ml/day for each animalThe results showed that HDL-C levels in the serum of rats fed with fish oil were markedly higher than Group 1 and 2 (p<0.01). The elevation of HDL-C was due to the increase of subgroup 2 of HDL-C, while subgroup 3 of HDL-C did not change obviously. The activities of serum lecithin cholesterol acyltransferase (LCAT) and lipoprotein lipase (LPL) were significantly higher (p<0.01) but the activity of hepatic endothelial lipase (HEL) was significantly low (p<0.05) in Gronp 3 as compared with Group 1 and 2. The present study demonstrated that fish oil could elevate HDL-C level through the following mechanisms: increasing activities of LCAT and LPL; inhibiting the activity of HEL.