大剂量维生素E对大鼠抗氧化和DNA损伤的影响

目的:探讨不同水平维生素E(VE)补充对大鼠抗氧化能力和DNA损伤的影响。方法:将大鼠分为正常对照组(N)、7倍剂量组(7N)、27倍剂量组(27N)、100倍剂量组(100N)共4组,饲养8w。实验结束前收集24h尿,实验结束后处死动物,取血分离血浆并收集淋巴细胞和红细胞膜,测SOD、GSH-Px活性、MDA含量,分析DNA损伤。结果:三个补充组血浆VE含量较对照组明显升高(P<0.05)。7倍剂量组,血浆SOD、血浆及红细胞膜GSH-Px活性明显高于其它三组;而血浆MDA含量显著低于其它三组。7倍剂量组中10μmol/LH2O2诱导的淋巴细胞DNA氧化损伤程度低于其它三组;DNA烷化损伤产物尿O6-甲基鸟嘌呤(O6-meG)含量,比正常对照组、100倍剂量组分别下降了100.62%、99.28%(P<0.05)。结论:按正常饲料VE水平,7倍剂量VE能提高大鼠抗氧化能力,降低DNA损伤;而过高剂量VE未观察到类似作用,并且可能降低机体遗传稳定性。

EFFECTS OF HIGH DOSE VITAMIN E ON ANTIOXIDATIVE FUNCTION AND DNA DAMAGE IN RATS

Objective: To investigate the effects of different levels of vitamin E(VE)on antioxidative function and DNA damage in rats. Method: Wistar rats were randomly divided into four groups including normal control group (N), 7 times(7N), 27 times (27N) and 100 times (100N) higher dietary VE group. Collected 24 h urine for determining O6-meG, and the rats were put to death after 8 w. The activities of SOD,GSH-Px, and level of MDA and DNA damage of lymphocytes were examined. Results: Plasma SOD activity,plasma and erythrocyte membrane GSH-Px activity were higher and plasma MDA was lower in 7N group than the other 3 groups. Lymphocyte DNA oxidative damages induced by 10 μmol/l H2O2 in 7N group were significantly lower and urinary O6-meG level in this group was significantly lower by 100.62%, 99.28% compared with N group and 100N group respectively. Conclusion: 7 time VE content of normal feed could effectively increase antioxidative function in the rats and protect against DNA damage. Too high dose of VE showed no such effects and whatever more the genetic stability might be decreased.