The Effects of cumulus cells on in vitro maturation of mouse germinal vesicle stage oocytes

Background: in vitro maturation (ivm) of oocytes is a promising technique to reduce the costs andavert the side-effects of gonadotropin stimulation for in vitro fertilization (ivf). the pregnancyrates from oocytes matured in vitro are much lower than those of in vivo stimulation cycles,indicating that optimization ofivm remains a challenge.objective: in this study, we investigated the effect of cumulus cells on maturation and fertilizationrate of immature oocytes (germinal vesicle).materials and methods: germinal vesicle (gv) oocytes were recovered from 6-8 weeks old balbc female mice 48hr after injection of 10 iv pregnant mare serum gonadotropin (pmsg). collectedoocytes were divided into two groups. group a: gv oocytes without cumulus (denuded oocyte).group b: gv oocytes with cumulus cells (cumulus-oocyte complex) . the oocytes in both groupswere cultured in tcm-199 medium in a humidified atmosphere 01 .)/ 0 ( ! ) 2 in air at 3ic. thematuration, fertilization and developme tal rates were recorded 'tfter 24hr.results: maturation, fertilization and developmental rates in ( nuded oocytos (do) were 65.1%,68.02 %, 78.63% respectively, and in cumulus-oocyte complex (coc) were 78.20%, 85.57% and85.05%, respectively. the maturation, fertilization and d velopmental rates of cae weresignificantly higher than those ofdo (p<0.05).conclusion: the results show that cumulus cells have beneficial effect on maturation, fertilizationand cleavage rates of mice oocytes.