Influential effect of age on oocyte morphometry, fertilization rate and embryo development following IVF in mice

Changes of oocyte quality and decreasing of ovarian follicle reserve in advanced age are the major challenges in infertility treatments. One factor associated with aging is the thickness of zona pellucida, which has adverse relation with embryo score. Although, there is no correlation between perivitelline space and granulation with embryo quality, an inversely correlation is observed between these two factors with subsequent embryo quality. The aim was to investigate the influence of age on the oocyte quality, fertilization rate and embryo development following in vitro fertilization setting in mice. NMRI mice (N = 21) were categorized into 3 groups regarding to their ages (groups I-III; 25, 30, 35 weeks old, respectively). Standard in vitro fertilization protocol was conducted for each group. After collection of the oocytes, three points of zona pellucida and perivitelline space diameters were measured in each group and mean values were calculated. Also, the number of oocytes, fertilization rate, the number of cleavage embryos and blastocyst formation were compared among the groups. All the changes were insignificancy age related, as the mean value of zona pellucida and perivitelline space diameters as well as the number of oocytes, rate of fertilization and 2 cells embryos were higher in group I compared to other groups. Also, there was significant difference between some evaluated parameters, such as the number of generated 4 cells cleavage embryos and blastocysts as well as oocytes degeneration rates. The advanced maternal age influenced negatively on the oocyte morphometry and cleavage and blastocyst embryo formation in animal model.