An in vitro comparative study of growth media, sera and FSH effects on the growth and maturation of Syrian mice preantral follicles and enclosed-oocytes

Developing a culture system for preantral follicles has important biotechnological implications due to the potential to produce a large number of oocytes for embryo production and transfer. To accomplish this goal، the present study was aimed to culture preantral follicles in the presence of different media، sera and FSH concentrations. Six-week-old preantral follicles (95 ± 5 μm) were cultured in North Carolina State University medium 23 (NCSU23)، tissue culture medium 199 (TCM199) and leibovitz-15 medium (L-15) for 6 days. Tissue culture medium 199 showed a significant increase in the follicle diameter (115 μm)، survival (39%)، oocyte maturation (32%) and germinal vesicle breakdown (GVBD) (29%) rates as compared to L-15 and NCSU23 (P<0. 05). A 6-day culture showed increased follicular growth as compared to 2، 4 and 8-days (P<0. 05). When the experiment was run with 1، 2، 5 and 10% fetal calf serum (FCS)، prepubertal gilt serum (PGS)، embryonic stem cell fetal calf serum (ESFCS) and hypogonadal mouse serum (hpgMS)، the 5% FCS showed increased follicle diameter (134 μm)، survival (52%)، oocyte maturation (49%) and GVBD (45%) as compared to control and other types of sera used (P<0. 05). While 100 mIU/ml FSH + 5% FCS in TCM199 showed a significant increase in follicle diameter (197 μm)، survival (96%)، oocyte maturation (91%) and GVBD (67%: P<0. 0001). So، it is concluded that the TCM199 medium، with the addition of 100 mIU/ml FSH and 5% FCS، is appropriate for the optimal in vitro growth of Syrian mice preantral follicles and enclosed oocytes.