HYDROSTATIC PRESSURE IMPROVES IN-VITRO MATURATION OF OOCYTES DERIVED FROM VITRIFIED-WARMED MOUSE OVARIES

摘要

Background: Cryopreservation has limited successes and in-vitro maturation is used to improve its results. Hydrostatic pressure (HP) plays an important role in follicular development. Objective: This study was designed to examine the effects of HP on in-vitro maturation of oocytes and cell death in cumulus cells derived from vitrified-warmed mouse ovaries.Materials and Methods: Preovulatory follicles were harvested from non-vitrified and vitrified-warmed 6-8 week-old female NMRI mouse ovaries and randomly assigned to following groups: non-vitrified (control), non-vitrified with HP exposure (treatment I), vitrified-warmed (treatment II) and vitrified-warmed with HP exposure (treatment III). The follicles of treatments I and III were subjected to HP (20 mmHg) for 30 min and after that all groups were cultured for 24h and assessed for in-vitro maturation of oocytes. The viability and apoptosis of cumulus cells and oocytes were assessed using supravital nuclear staining and TUNEL assay, respectively.Results: Oocytes harvested follicles in both control and treatment II had a significantly lower percentage of metaphase II oocytes (MII) than the treatment I and III (23.5