大豆异黄酮对~(60)Co γ射线所致氧化损伤的保护作用研究

目的:研究大豆异黄酮(SI)对60Coγ射线照射小鼠氧化损伤及组织细胞DNA损伤的保护作用。方法:将小鼠随机分为SI高、中、低剂量组(333、167、83mg/kgbw)、模型组和对照组。辐射前,各剂量组每日给予不同剂量SI;模型组和对照组给予等体积0.5%羧甲基纤维素钠(CMC-Na)溶液。30d后,除对照组外,各组给予15Gy60Coγ射线全身一次性照射。照后D4处死动物,测定肝匀浆MDA含量,SOD和GSH-Px活性。同时各组分别取3只小鼠的肝、脾、肾、血进行彗星实验以观察细胞DNA损伤情况。结果:与对照组比,模型组MDA含量显著增高(P<0.01),SOD和GSH-Px活性显著降低(P<0.05);与模型组比,SI剂量组MDA含量显著降低(P<0.05)、SOD和GSH-Px活性显著增高(P<0.05)。模型组4种组织细胞之间DNA损伤程度不同,均显著高于各自的对照组(P<0.05),且SI剂量组的DNA损伤程度显著低于模型组(P<0.05),并随着SI剂量的增加,DNA损伤程度相应减轻。结论:SI对辐射所造成的氧化及DNA损伤具有保护作用。

STUDY ON THE PROTECTION OF SOY ISOFLAVONES AGAINST OXIDATIVE DAMAGE INDUCED BY 60Co γ-RAY IRRADIATION

Objective: To investigate the protective effect of soy isoflavones (SI) against DNA damage and impairment of antioxidative system in mice irradiated by 60Co γ-rays. Method: Fifty mice were randomly divided into five groups. Three SI supplementation groups were supplied with different dosages of SI by intragastric administration daily.Model and control group were given 0.5% sodium carboxymethyl cellulose (CMC-Na) everyday. It lasted 30 days ,then all mice were irradiated by 60Co γ-rays once except control group. All animals were killed in D4 after irradiation. MDA contents, SOD and GSH- Px activities in liver were measured by colorimetry. DNA integrity of liver, spleen, kidney and blood cells was analyzed by comet assay. Results:MDA contents of model group were much higher than those in control group (P< 0.01), meanwhile, SOD, and GSH-Px activities were much lower (P<0.05). Compared with model group, MDA contents of SI high dose group decreased significantly (P<0.05), and the changes of SOD,GSH-Px activities were reverse (P<0.05). As compared with control group ,the degree of DNA damage in model group was much higher(P<0.05). Then in SI groups, the degree of DNA damage was much lower than thatof model group (P<0.05) dose-dependently. Conclusion:SI has protective effect against oxidative stress and DNA damage irradiated by 60Co γ-rays in mice.