中文摘要：

目的：了解雌马酚在二甲基苯蒽[7,12-dimethyl-benz（a）anthracene,DMBA]诱导的去势大鼠乳腺肿瘤发生中的抗氧化作用。方法：将48只雌性SD大鼠行双侧卵巢切除术,随后按体重水平随机将其分为空白对照组、阳性对照组、雌激素对照组和雌马酚高、中、低剂量组。除空白对照组外,其余各组大鼠经口给予5 mg DMBA,每周对其触诊,了解乳腺肿瘤发生情况并记录体重和摄食量。24周后处死大鼠,观察并计算各组大鼠乳腺肿瘤发病率,检测大鼠血浆中超氧化物歧化酶（superoxide dismutase,SOD）活力和丙二醛（malondialdehyde,MDA）、8-羟基脱氧鸟苷（8-hydroxy-2-deoxyguanosine,8-OHdG）含量,Western blotting法检测肝脏组织中NF-E2相关因子（nuclear factor E2related factor 2,Nrf2）的表达。结果：不同剂量的雌马酚能显著降低去势大鼠的体重和摄食量、乳腺肿瘤发病率及MDA含量,并能增强大鼠肝脏Nrf2蛋白的表达,而对大鼠血浆SOD活力、8-OHdG含量则无显著影响（P〉0.05）。结论：不同剂量的雌马酚能够显著降低去势大鼠的乳腺肿瘤发生率,该作用可能与减少摄食量、降低体重、减少机体内MDA的含量、诱导Nrf2蛋白的表达有关;雌马酚对去势大鼠抗氧化作用可能受构型、作用时间等因素影响,有待于进一步研究。

英文摘要：

Objective：To study the effect of equol on the incidence of breast tumors induced by 7,12-dimethylbenz（a） anthracene（DMBA） in ovariectomized rats.Methods：In the study,48 female ovariectomized SD rats were randomly divided into 6 groups according to their weights：blank control group,fed on an AIN-93G diet;model group,fed on an AIN-93G diet;estrogen control group,fed on an AIN-93G diet supplemented with 0.25 mg/kg diethylstilbestrol;and low,medium and high doses of equol groups,fed on an AIN-93G diet supplemented with 100,200 and 400 mg/kg diet of equol,respectively.The animals were palpated to examine the breast tumor,body weight and dietary intake of each rat per week.The data were recorded.At the end of the experiment,the incidence of breast tumor was calculated and the sera were collected for the detection of SOD,MDA and 8-OHdG levels.The expression of Nrf2 in liver was assessed by Western-blotting.Results：Equol decreased the rats＇ body weights,dietary intakes,breast tumor incidence and MDA levels,but had no effect on the levels of SOD and 8-OHdG in the sera.The expression of Nrf2 was up-regulated dose-dependently in equol groups.Conclusion：Supplementation of equol could decrease the incidence of breast tumor in ovariectominzed rats.This effect may result from the reduction of body weight,intake of diet,MDA level in the sera and up-regulation of expression of Nrf2.The effect of equol may be influenced by many factors,such as the structure of equol,which should be further studied.