Follicular fluid and cumulus cells synergistically improve mouse early embryo development in vitro

Background and Despite the rapid development of assisted reproduction techniques (ÂRT) in recent years, implantation rates after replacement of embryos into the uterine cavity remains low. Ân important approach to improve embryo quaility and implantation rates has been the use of coculture systems. Hence this study was undertaken to evaluate the influence of cumulus cells monolayer in follicular fluid on mouse early embryo development in vitro. Ône cell embryos were obtained from Swiss white mouse after superovulation with HMG and hÇG. Çumulus cells were prepared from mouse egg-cumulus mass after a short exposure to medium containing hyaluronidase. These cells were seprated from red blood cells using a percoll gradient. Follicular fluid was collected from patients undergoing an ÏVF program during oocyte pick-up. Granulosa cells monolayer were prepared in Follicular fluid (FÇ) and Ham’s F10 medum (HÇ). Mouse one-cell embryos were cultured in FÇ, HÇ, Ham’s F10 (HF) and follicular fluid (FF) for 120 hours. Ônly 10% of embryos passed the 2-cell growth block in HF. Howerer, the proportion of 2-cell block passed emboryos were 21%, 27% and 69% in FF, HÇ and FÇ respectively which are significantly different from HF (P<0.05). The differences between FÇ and two other treatment were also significant (P<0.001). Ïn FÇ, 35% of 4-cell embryos continued to grow to blastocyst stage whereas only 8.9% and 7.7 % of 4-cell embryos in HÇ and FF reached this stage and no embryos developed to blastocyst in HF. The blastocyst rate in FÇ was significantly higher (P<0.001). Ït can be concluded that follicular fluid and cumulus cells in monolayer form may synergistally improved early embryo culture conditions compared with all other treatments.