Comparison Of Two-Dimensional And Three-Dimensional In Vitro Culture Systems For Maturation Of Preantral Mouse Ovarian Follicles

ObjectiveThe aim of this study was to compare the two-dimensional and three-dimensional in vitroculture systems of preantral mouse ovarian follicles in follicular survival, growth, theability of estradiol production, and oocyte maturation, in order to assess the optimaltechnique for mouse preantral follicle in vitro culture.MethodsFollicles were isolated by mechanical dissection from C57BL/6J female mouse on12-14days old, selected with the diameter of80-130μm and intact structure. Then cultured intwo-dimensional and three-dimensional in vitro culture systems respectively in α-MEMmedium with10%fetal calf serum,5.5mg/ml PNa, ITS(5ug/ml insulin，5ug/ml transferrine,5ng/ml selenium),5ng/ml recombinant EGF, and100mIU/ml recombinant FSH for7days.All the follicles were observed and measured by inverted microscope and Image J every2days, the medium substituted every2days were detected by radioimmunoassay forhormone. ResultsIn two-dimensional and three-dimensional in vitro culture systems, the ratio of survival andatresia were no difference; the increase rates of follicles of in two-dimensional culturesystem were faster than three-dimensional culture systems，the difference initiated from day3（1.12±0.154:1.11±0.148）and arrived to the peak at day7；the production of estradiolwere no difference； the proportion of oocytes that underwent nuclear maturation tometaphase I stage（s61%：4%） and metaphase I（I17%：8%） after culture were significantdifferent when the follicles were grown In two-dimensional and three-dimensional in vitroculture systems.ConclusionIn two-dimensional in vitro culture systems，the rates of mouse preantral follicles and theproportion of oocytes to retrieve their meiosis were higher than that in three-dimensiona.Thus the two-dimensional in vitro culture systems was more suitable for mouse preantralfollicular growth and oocyte maturation.