Effect of (BETA)-Mercaptoethanol with and without BSO (DL-Buthionine Sulfoximine) on Resumption of Meiosis. in vitro Maturation and Embryo Development of Immature Mouse Oocytes

Introduction: the purpose of this study was to evaluated the effect of 13mercaptoethanolon resumption of meiosis, in vitro maturation of immaturemouse oocytes and resulting embryo development with and without sso(dl-suthionine sulfoximine).material and methods: germinal vasicle (gv) were recovered from 6-8weeks old nmri ovaries and cultured in maturation medium in memosupplemented with 7.5iu/ml hcg, 100m1u/ml rhfsh, 5% fcs (control group)and adding 100~m (beta)-mercaptoethanol (group 1) or with 5mm bso + 100~mp-mercaptoethanol (group 2) for 24h. the matured oocytes then werefertilized and cultured for 5 days. fertilization and development wereaccomplished in t6 medium.results: the percentage of gv oocytes reaching to metaphase i (orundergo gvbd) were 78.5%, 85%, 86% in control group, group 1 and group2 respectively, that no significant difference was detected between groups.the proportion of oocytes that progressed to the metaphase ii (mil) stagewas minimum within 5mm bso group (group 2) and maximum within 13mercaptoetanolgroup (group 1) with significant difference comparing withcontrol and each other (p(less than)o.05). the percentage of embryos reaching tomorula stage within p-mercaptoetanol group was significantly higher thanthe control group (5% and 12.2% respectively). none of oocytes treated withbso could pass the 8 cell stage.conclusion: p-mercaptoetanol enhances ivm and improves embryodevelopment. while adding bso into the maturation medium even with (beta)mercaptoetanoldecreases maturation and declines the embryo development.