高同型半胱氨酸血症致动脉粥样硬化的实验研究

The experimental study of artherosclerosis induced by hyperhomocysteic acid

目的通过大鼠灌胃给予蛋氨酸复制高同型半胱氨酸血症（HHcy）动物模型，观察HHcy大鼠动脉粥样硬化（As）的病理改变及与氧化应激的关系。方法Wistar雄性大鼠，体重120～150g，实验组每天灌胃给予蛋氨酸0．75g／ks，2次／d；叶酸、维生素B12（VB12）干预组每天灌胃给予蛋氨酸0．75g／kg，2次／d＋叶酸2．5mg／kg＋VB1210μg／kg；对照组每天给予等容积生理盐水，连续给药10w，处死动物取血及胸主动脉。在平左心耳下缘水平取胸主动脉冰冻切片，HE染色，光镜下（X100）照相，测量动脉平滑肌相对厚度（mm），除以体重计算出每100g体重动脉平滑肌厚度指数（SMTI）。检测血浆同型半胱氨酸（Hcy）、丙二醛（MDA）和谷胱甘肽过氧化物酶（GSH-Px）、超氧化物歧化酶（SOD）活性，组间比较t检验。结果实验组大鼠灌胃给予蛋氨酸可诱发HHcy（与对照组比较P〈0．01），血浆MDA含量生高（与对照组比较，P〈0．01），GSH-Px、SOD活性降低（与对照组比较，P〈0.01），SMTI（与对照组比较，P〈0．01）。叶酸、VB12干预可降低SMTI（与实验组比较，P〈0．01），血浆Hcy浓度下降（与实验组比较，P〈0．01），MDA降低（与实验组比较，P〈0．01），GSH-Px、SOD活性升高（与实验组比较，P〈0．01）。结论高蛋氨酸可诱发HHcy，通过导致动脉平滑肌增生及过氧化状态致AS。叶酸、VB12对HHcy诱发的AS具有拮抗作用，并改善其引起的高过氧化状态。

Objective To copy a practical rat model for hyperhomocysteic acid in vitro by lavage methionine and observe the relationship between the pathological changes of arteries with artherosclerosis and oxidative stress. Methods Wistar male rats with the weight of 120-150 g were randomized assigned into three groups. By intragastric administration the experimental group was given with methionine （0. 75 g/kg） twice one day; Besides methionine the group with drug intervention were given folic acid （2. 5 mg/kg） and vitamine B12 （ 10 μg,/kg） each day, however the control group was only given the normal sodium of the equal volume each day. Ten weeks later, the blood and thoracic aorta were isolated. In the level of lower edge of the left atrial appendage, the thoracic aorta was obtained to make the frozen sections stained with hematoxylin and eosin and take pictures under light microscope. After measuring the thickness （mm） of the arterial smooth muscle, the arterial smooth muscle thickness index per 100 g （the thickness/the weight） were detected. Meanwhile the activity of plasma homocysteic acid, malondialdehyde （MDA）, glutathione peroxidase （GSH-Px） and superoxide dismutase （SOD） were measured. Eventual- ly a corresponding statistical analysis t-test of the groups were conducted. Results Methionine administation by lavage induced HHcy, plasma MDA contents increased compared with those in control group （all P 〈0.01 ）. Folic acid and vitamine B12 lowered the arterial smooth muscle thickness index, decreased Hcy content, reduced MDA, increased GSH-Px, SOD activities compared with those in experimental group （ all P 〈 0. 01 ）. Conclusions The high level of methionine could induce hyperhomocysteic acid （HHcy） and subsequently arthero- sclerosis by inducing hyperplasia of arterial smooth muscle and the state of peroxidation. The folic acid and vitamine B12 could inhibit artherosclerosis and improve high level of peroxidation state that induced by HHcy.