L-arg对高胆固醇血症兔血管反应性的影响

The Effect and Its Mechanism of L-arginine on the Responses of thoracic Aorta in Hypercholesterolemic Rabbits

本研究观察ＮＯ前体物Ｌ－ａｒｇ的抗动脉粥样硬化作用机理。将１６只雄性新西兰白兔按体重随机分为３组：正常对照组（Ｄ组，ｎ＝５），单纯胆固醇组（Ｃ组，ｎ＝６）和复合组（Ｌ组，ｎ＝５）。实验开始前及实验第５周和第１０周抽血检测血浆总胆固醇，第１０周处死动物，检测血浆和胸主动脉组织中内皮素－１（ＥＴ－１）、环－磷酸鸟苷（ｃＧＭＰ）含量，并测试了胸主动脉环对去甲肾上腺素（ＮＥ）的反应性。结果发现Ｌ－精氨酸对血浆总胆固醇无明显影响，但可使血浆及组织中ＥＴ－１含量显著下降，ｃＧＭＰ含量上升，补充ＮＯ前体物可改善胸主动脉环对缩血管物质去甲肾上腺素的反应性。由此可见，补充Ｌ－ａｒｇ可纠正高胆固醇引起的ＥＴ－１／ｃＧＭＰ失衡，具有一定的抗动脉粥样硬化作用。

This study was to seek the affect of L-arginine in the prevention of atherosclerosis in rabbit.Sixteen male rabbits were randomly divided into three groups:normal control group(D,n=5,fed with normal rabbit forage),cholesterol control group(C,n=6,received forage enriched with 1% cholesterol) and complex group(L,n=5, 1% cholesterol diet supplemented with 2.25%L-arginine).Before the initiation of and the fifth week and the tenth week,blood samples were collected from all of the rabbits for measurement of plasma total cholesterol(TC).At the end of the experiment,the rabbits were sacrificed and blood samples were collected in order to measure the level of plasma endothlin-1(ET-1)and cGMP,and aortas were harvested from all of the rabbits for measurement of the responses to norepinephine and the level of ET-1 and cGMP in aorta tissues.Compared with the C group,there was no significant alteration in plasma TC in complex group,but the level of ET-1 in plasma and tissues were lowered obviously(P<0.05),the level of cGMP increased significantly in the aorta and plasma(P<0.05),and the responses to NE attenuated.All those suggested that L-arginine could regulated imbalance between ET-1 and cGMP in plasma and aorta tissues,and it inhibit atherosclerosis.