大豆异黄酮对老龄大鼠雌激素水平和子宫雌激素受体表达的影响

目的探讨大豆异黄酮（soy isoflavones,SIF）对老龄大鼠雌激素水平和雌激素受体表达的影响。方法将40只16月龄雌性SD大鼠随机分为高、中和低剂量大豆异黄酮3个实验组（H-SIF,M-SIF和L-SIF）和1个对照组,每天分别按1005、0和25 mg/（kg.bw）剂量的大豆异黄酮进行灌胃,对照组灌服生理盐水。42 d后称重,股动脉放血处死动物收集血清、摘取子宫称重并冷冻保存。采用放射免疫法测定血清中雌二醇（E2）、睾酮（T）、泌乳素（PRL）、促黄体生成素（LH）和促卵泡激素（FSH）的含量;RT-PCR检测子宫雌激素受体α（ERα）基因的表达。结果与对照组相比,3个实验组血清中E2和PRL都升高,LH和FSH都降低,其中高剂量组差异有显著性（P〈0.05）;子宫重量无明显差异;子宫ERα表达呈下降趋势,但无统计学意义。结论大豆异黄酮能调节老龄大鼠血清中的雌激素水平,且有剂量依赖性;大豆异黄酮对老年大鼠子宫重量和子宫ERα的表达无影响。

Effect of Soy Isoflavones on Endogenous Estrogen Level and Uterine Estrogen Receptor Expression in Aged Rat

Objective To investigate the effect of soy isoflavones（SIF） on endogenous estrogen in aged rats.（Methods Forty） 16-month-old female Sprague-Dawley rats were randomly divided into 4 groups： high-,medium-and low-dose SIF groups and the control group,in which soy isoflavones in a dose of 100,50,25 and 0 mg/kg body weight were given,respectively,by gavage daily.Six weeks later,plasma samples as well as uterus were collected after the rats were sacrificed,and analyzed for E_2,PRL,T,FSH and LH by radioimmunoassay.RT-PCR was used to investigate the expression of the estrogen receptor alpha（ERα）.Results The levels of E_2 and PRL in 3 SIF groups increased whereas that of FSH and LH decreased when compared with those in the control group.There was a statistically significant difference between the high-dose SIF and the control groups.There is no significant difference in the uterus growth between the control and SIF groups.SIF treatment resulted in a decreasing trend of the ERα expression,although the difference was not significant.Conclusions Soy isoflavones can exert an influence on endogenous estrogen levels of estradiol and gonadotropins in aged rats in a dose-dependent manner whereas no significant impact on the uterus growth and the ERα expression.