Steroid Production and Follicular Development of Neonatal Mouse Ovary during in vitro Culture

BACKGROUND: The aim of this study was to investigate follicular growth and steroid production in neonatal mouse ovary during in vitro culture. MATERIALS AND METHODS: In this experimental study, 7-day-old mouse whole ovaries were cultured in α-MEM (medium supplemented with 100 mIU/ml recombinant follicle stimulating hormone, 1% insulin, transferrin and selenium (ITS), 5% fetal bovine serum (FBS), 100 IU/ml penicillin and 50 μg/ml streptomycin for 7 days. The size of whole ovary was determined as mean area during culture. The survival rates of isolated preantral follicles after culture were assessed using trypan blue staining after being mechanically isolated. Histological evaluation of whole ovary was done by hematoxylin and eosin staining. 17-β estradiol, progesterone and dehydroepiandrosterone concentrations in the medium were measured during culture. RESULTS: The mean area of ovary increased after culture (1.47 vs. 0.21 mm(2)). The survival rate of isolated follicles in ovary after culture was 99.2%. There was a significant decline in the percentage of primordial follicles after seven days of culture (91.8 ± 0.2% vs. 65.1 ± 1.1%), whereas the rate of preantral follicles increased significantly (4.6 ± 0.4% vs. 29.2 ± 0.5%). The levels of estradiol, progesterone and dehydroepiandrosterone also increased significantly after culture (p<0.001). CONCLUSION: These results show that the growth and development of primordial follicles in contrast with hormonal production decreased during in vitro culture of neonatal mouse ovaries.