大豆异黄酮对大鼠血脂的影响及其体内外抗氧化作用研究

目的：观察大豆异黄酮（SI）对高脂饮食大鼠血脂、血液及肝脏丙二醛（MDA）、超氧化物岐化酶（SOD）及肝脏脂肪病变的影响,以及其主要成分之一金雀异黄素对过氧化氢损伤的ECV304内皮细胞有无保护作用。方法：根据血清总胆固醇（TC）水平,50只雄性Wistar大鼠分为5组：正常对照、高脂饮食对照组和3个SI治疗组。3个SI治疗组分别每日灌胃给予SI30、60、120mg/kg,对照组则给予相应的溶媒,持续9周。治疗第2、4、9周末,测定血清TC、三酰甘油（TG）、低密度脂蛋白（LDL）、高密度脂蛋白（HDL）。治疗结束时,测定红细胞和肝匀浆SOD活力,血清和肝匀浆MDA含量,并观察肝脏病理变化。以MTT法观察与不同浓度的金雀异黄素体外孵育一定时间后的ECV304内皮细胞对抗过氧化氢氧化损伤的能力。结果：SI30、60、120mg/kg无改善血清TC、LDL、TG、HDL的作用,肝脏病理结果也与血脂结果相似。但是与高脂饮食对照组相比,大鼠红细胞及肝脏的SOD活力明显升高,而血清及肝脏MDA含量也有一定程度降低（P〈0.01,P〈0.05）。对于过氧化氢引起ECV304细胞损伤,金雀异黄素25、50、100μmol/L有剂量依赖性保护作用。结论：大豆异黄酮不能改善高脂饮食大鼠的血脂,不能抑制其肝脏脂肪病变。但其有一定体内外抗氧化作用。

Effects of soy isoflavones on serum lipids and the antioxidative effects in vivo and in vitro

AIM： To observe the effects of soy isoflavones （SI） on serum lipids, malondialdehyde （MDA） and superoxide dismutase （SOD） of blood and liver in rots fed with high cholesterol diet, and the protective effects of genistein on H2O2 injured ECV304 cell in vitro. METHODS： According to serum cholesterol（TC） level, fifty male Wistar rots were divided into 5 groups, normal control group （NC）, high cholesterol control group （HC） and three SI treatment groups, three SI treatment groups were administrated with SI 30, 60, 120 mg/kg intragastrically （ig）, and the two control groups were administrated with solvent for 9 weeks. At the end of 2,4,9 weeks, serum TC, triglyceride （TG）, high-density lipoprotein （HDL）, low-density lipoprotein（LDL） were measured. At the end of treatment, SOD activities in RBC and liver, serum and hepatic MDA levels were measured. Hepatic pathological changes were also observed. We also detected survival rate of ECV304 on H2O2 injure after incubated with different concentrations of genistein with MTT assay. RESULTS： SI 30, 60, 120 mg/kg could not reduce serum lipids levels. Hepatic pathological resuits were also in consistent with serum lipids. But SOD activities in RBC and liver were improved and serum and hepatic MDA levels were decreased in SI treatment groups （P 〈 0.05, P 〈 0.01）. In our study, we also observed that genistein 25, 50, 100 μmol/L could protect ECV304 ceils injured by H2O2 dose-dependenly. CONCLUSION： Soy isoflavones could not improve serum lipids and prevent hepatic fatty degeneration in cholesterol-fed rats. However, they have antioxidative effects both in vivo and in vitro.