大豆黄酮影响青春期小鼠乳腺发育的潜在机制OACSTPCD

[Objectives]The phytoestrogen daidzein(DZ)was used to act on adolescent mice to investigate its effects on mammary development by increasing 1,7-β-estradiol(E2)level and upregulating estrogen receptor β(ERβ)expression,providing a basis for DZ and other phytoestrogens in animal production and clinical application.[Methods]Forty-eight 2-week-old female C57BL/6 mices randomly divided into 3 groups:control group,intraperitoneal injection of sterile PBS;DZ group,intraperitoneal injection of DZ(100 mg·kg-1·d-1);positive control group,intraperitoneal injection of E2(0.2 mg·kg-1·d-1).On the 21 and 28 day,8 mices from each group were randomly selected and their blood was collected,the content of E2 in the blood was measured on the basis of group.After death,the mammary glands were immediately isolated and weighed to measure the index of mammary glands and detect the content of E2 in mammary tissues.The expression of proliferating cell nuclear antigen(PCNA)protein was detected by immunohistochemistry.Cell cycle-related protein and estrogen receptor β(ERβ)protein expression levels were analyzed by Western blot.[Results]Compared with the control group,DZ treatment significantly increased the body weight and daily feed intake of mice on the 21 and 28 day,increased E2 levels in blood and breast tissues of mice on the 21 day,but not significantly(P>0.05)and significantly increased them on the 28 day(P<0.05).Similarly,E2 treatment also significantly increased the content of E2 in blood.DZ treatment had little effect on the mammary index of mice on the 21 day,but significantly increased the index on the 28 day(P<0.05);E2 treatment had the same trend(P<0.05).HE staining showed that DZ and E2 treatments significantly increased the numbers of ducts and PCNA positive cells in breast tissues of mice on the 21 and 28 day(P<0.01).Western blot results showed that DZ and E2 treatments up-regulated the protein expressions of cyclinD1,cyclinB1 and ERβ in breast tissues of mice,and specially significantly up-regulated the protein expressions of cyclinD1,cyclinB1 and ERβ on the 28 day(P<0.05).[Conclutions]Phytoestrogen DZ could promote the development of mammary gland of adolescent mice,and promote the proliferation and division of mammary cells,which might be related to the increase of endogenous E2 level and ERβ receptor.