Effects of estrogen on expression of Bcl-2 and Bax in rat hypothalamus

In order to elucidate the regulating mechanism of estrogen on expression of Bcl-2 and Bax in rat hypothalamus,the expression of Bcl-2 and Bax in the hypothalamus of SD rats after ovariectomized and treated with 17β-estradiol was detected by Streptavidin-Peroxidase(SP) immunohistochemistry.The results showed that Bcl-2 and Bax were expressed extensively in the hypothalamus,mainly in the nucleus dorsomedial hypothalamus,nucleus ventromedial hypothalamus,nucleus arcuatus hypothalamus,nucleus paraventricular hypothalamus and nucleus supraopticus hypothalamus.Bax and Bcl-2 mainly existed in the plasma,cytoplasmic membrane and nuclear membrane,and also observed in the neurites.In an ovariectomized group,the expression of Bcl-2 decreased,while the expression of Bax increased.After 17β-estradiol treated,Bcl-2 expressed stronger and Bax expression were reduced.All the results showed that estrogen could prevent the hypothalamus neurons from apoptosis by down-regulating the expression of Bax and up-regulating Bcl-2 at different levels.