卫生研究

目的研究三羟异黄酮对断乳大鼠生殖发育的影响。方法将3周龄幼鼠48只按体重随机分为3组,雌雄各8只,口饲给予含不同剂量三羟异黄酮的基础饲料[对照组0mg/(kg.d),中剂量组20mg/(kg.d),高剂量组100mg/(kg.d)],待各组大鼠发育至9周龄时,测雌鼠血清雌二醇水平,雄鼠血清睾酮水平;待各组大鼠发育至13周龄时,分离雌鼠子宫、卵巢,雄鼠睾丸进行病理检查,用Western blotting方法测定雌激素受体(ER)的表达水平。结果与对照组相比,9周龄时雌鼠血清雌二醇水平降低,雄鼠血清睾酮水平升高;13周龄时,雌鼠体重和摄食量下降,阴道开放提前,生殖器与直肠间距(AGD)减小,卵巢称重减少。病理切片显示雌鼠子宫腔扩大,子宫扩张,血清雌二醇水平有所降低,子宫雌激素受体ER表达量降低;雄鼠摄食量10周龄左右有所升高,血清睾酮水平升高,但体重无明显升高,睾丸下降时间未见提前,睾丸称重无差别,病理切片未见异常。结论三羟异黄酮对断乳后大鼠的生殖指标影响较大,其中对雌性大鼠的影响大于雄性大鼠,但是对大鼠体重和摄食量的影响主要在其成年后,并且此种影响与其激素水平和受体表达有关。

Objective To investigate the effects of dietary genistein on the development of young rats. Methods SD rats aged three-week were randomly divided into three groups according to their weight (eight male and eight female). Each group was fed a diet containing genistein at levels of 0, 20 and 100mg/kg. Several development indices were observed each week. At the age of 9 weeks, blood samples were collected and the plasma estradiol level of female rats and plasma testosterone level of male pups were measured. At the age of 13 weeks, organs(ovary and uterus in female, testes in male) were examined for histopathological changes and the expression of the estrogen receptor was measured by Western blotting.Results The plasma estradiol level of female rats increased and the plasma testosterone level of male rats decreased at the age of 9 weeks compared to the control group. At the age of 13 weeks, decreased body weight, food consumption, anogenital distance(AGD) and overy weight in female rats were observed. Also, the vaginal open time of female pups was earlier than control group. Histopathology showed that the cavity of uterus was larger than control group. Otherwise, treatment with genistein caused reduction in the plasma estradiol level of female rats and the expression of estrogen receptor-α in uterus. There were few changes of male rats′ body weight, testicular descent, testes weight and histopathology except that the increased food consumption from 10-week-old and plasma testosterone level. Conclusion Genistein exposure could effect on both sexes of young rats' development. The effects on female rats were much more than that on male rats and the effect of rats body weight and food consumption was mainly after their growing up. Although the mechanism of these effects are still obscure, it seems that the change of hormone level and expression of estrogen receptor have some relation with these effects.