Survival, Fertilization and Developmental Rates of Cryotop-Vitrified Oocyte and Embryo Using Low Concentrated Cryoprotectants

The preserving embryos، the risk of multiple pregnancies، the existence of factors in stimulated uterine cycle، are important forces in perfecting embryo cryopreservation. The aim of current study was to assess Survival، Fertilization and Developmental Rates (SRs، FRs، DRs) of the mouse oocytes and embryos using cryotop and low concentrated cryoprotectants solutions. Mouse C57BL/6 oocytes and embryos were collected. Oocytes SRs، FRs، DRs were recorded after cryotop-vitrification/ warming. As well as comparing fresh oocytes and embryos، the data obtained from experimental groups (exp.) applying 1. 25، 1. 0، and 0. 75 Molar (M) CPAs were analyzed in comparison to those of exp. adopting 1. 5 M CPAs (largely-used concentration of EthylenGlycol (EG) and Dimethylsulphoxide (DMSO)). The data of oocytes exposed to 1. 25 M CPAs were in consistency with those exposed to 1. 5 M and control group in terms of SR، FR and DR. As fewer concentrations were applied، the more decreased SRs، FRs and DRs were obtained from other experimental groups. The results of embryos were exposed to 1. 25 M and 1. 0 M was close to those vitrified with 1. 5 M and fresh embryos. The results of 0. 75 M concentrated CPAs solutions were significantly lower than those of control، 1. 5 M and 1. 0 M treated groups. CPAs limited reduction to 1. 25 M and 1. 0 M instead of using 1. 5 M، for oocyte and embryo cryotop-vitrification procedure may be a slight adjustment.