Objective:To explore the roles of estrogen receptorα(ERα)and estrogen receptorβ(ERβ)Informs on follicular development and maturation of mice and to comprehend if there is difference between ERαand ERβin follicles at all stages between in vivo maturation and in vitro culture.So as to learn more about the basic study of in vitro mature of immture oocyte by detecting ERαand ERβexpression in theca cells

interstitial cells and follicles of different stages of ovary in mature mice

and by culturing preantral follicles of immature mice and detecting detecting ERαand ERβIsoforms expression in cu- tured follicles.Method:Detect distribution of ERαand ERβIsoforms on the ovaries of mature mice and follicles from cultured preantral follicles of immature mice by immunohistochemistry with rabbit-anti-mouse polyclonal antibody of ERαand ERβ

and quantitatively evaluate the staining intensity of follicles at different stages.Results:ovarian immunohistochemistry of mature mice showed that Positive ERαstaining was found in thecal cells and stromal cells and no positive ERβstaining in these two cells.ERαand ERβstaining were both negative in granular cells of primordial follicle

ERβstaining was positive in granular cells from primary up to preovulatory follicles

there was no positive staining of ERαin granular cells of these follicles. The most intense ERβstaining was observed in granular cells of small antral follicles

in big antral follicles ERβstaining of granular cells was lower

and much more lower in granular cells of preovulatory follicles

quantitatively analysis of the ERβ- staining intensity in granular cells of follicles at different stages showed that there was no significant difference in staining den- sity of granular cells between primary follicle and small preantral follicles

but there is significant difference between all other follicles(P<0.01).The gradation of ERβstaining intensity of all follicles from strong to weak was small antral follicles

big antral follicles

preovulatory follicles

big preantral follicles

small preantral follicles.ERαand ERβstaining were both positive in oocytes. The immunostaining was the same in granulose cells and oocytes of follicles between mature and immature mice

as well as the result of staining intensity of ERβquantitatively analysis in granular cells of follicles at different stages.Conclusion:The expres sion of ERαand ERβin follicles of all stages was coincident between in vivo maturation and in vitro culture.ERβplayed a capital role on follicular development.