Correlation of somatic cell steroid secretion and quality of generated oocytes after in-vitro stimulation of mouse follicles

Purpose: To test the possibility of follicular somatic cell steroidogenesis as a marker for quality of their embraced oocytes. Methods: Mechanically isolated mouse preantral follicles were cultured and matured in-vitro (IVC/IVM) for study. Results: During IVC/IVM, oogenesis occurred concomitantly with folliculogenesis in a coordinated manner and simultaneously with progressive increments of somatic cell steroidogenesis. Follicular E₂ production of matured oocytes were significantly higher than that of immature ones. The majority of MII oocytes (32/36) and all developed blastocysts(12/12) were associated with active E₂ production prior to ovulation. In this study, 18 MII oocytes met both requirements for active and optimal E₂ production. 13 of them were fertilized and 10 developed into blastocysts. Conclusion: Active somatic cell steroidogenesis prior to ovulation and an optimal steroid milieu at ovulation are prerequisites for generation of competent oocytes after follicular maturation in-vitro.Predictability of somatic cell steroidogenesis for oocyte competency after follicular IVC/IVM.