植物雌激素大豆黄酮对断奶期小鼠乳腺退化的减缓作用研究OACSTPCD

To investigate the effects of Daidzein(DZ)on mammary gland involution in weaned mice,48 pregnant mice were used and ran-domly divided into a control group(treated with sterile PBS)and a DZ group(intraperitoneal injection of 100 mg/kg),once daily,for 7 days.After normal delivery,the mice were forced to wean on the 10th day of lactation.Then,the rodents were euthanized on 1,3 and 7 days after weaning,respectively,and their blood and mammary tissues were sampled for analysis.All the mammary tissues were weighed to calcu-late the mammary index.The enzyme-linked immunosorbent kit(ELISA)was used to detect serum estradiol(E2),prolactin(PRL)and insulin-like growth factor-Ⅰ(IGF-Ⅰ)levels in the mice.The morphological changes of mammary tissue were analyzed with HE staining.Western blotting was used to detect Bax and Bcl-2 protein expression in the breast tissue.The results showed that compared with the control group,the mammary index was increased in the DZ group on one-day weaned mice,while the index was lower than that of the control group on 3 and 7 days of weaning.Compared with the control group,on 1 day after weaning,the levels of serum PRL(P＜0.01)and IGF-Ⅰ(P＜0.01)were significantly increased in the DZ group.Three days after weaning,the serum PRL and E2 concentrations in the DZ group were significantly increased(P＜0.01).The HE staining results showed that,compared with the control group,the adipocyte area ratio in the breast tissue of the weaned female mice in the DZ group was significantly decreased(P＜0.05),and the acinar area ratio was increased(P＞0.05).Compared with the control group,the expression of Bcl-2 was significantly up-regulated by DZ(P＜0.01),while Bax expression was significantly decreased on 3 days after weaning(P＜0.01),and the expression of Bax and Bcl-2 proteins was significantly increased on 7 days after weaning(P＜0.01).The ratio of Bcl-2/Bax was significantly increased on 1 day and 3 days after weaning(P＜0.01)in the DZ group,but decreased on 7 days of weaning(P＞0.05).These results indicated that DZ affected the serum IGF-Ⅰ,PRL and E2 levels in the weaned female mice,and increased the ratio of Bcl-2/Bax expression to inhibit the process of apoptosis and decrease the area ratio of adi-pose cells,which suggested that DZ might delay the early involution of mammary gland by inhibiting the apoptosis of mammary gland cells in female mice.