Effect of β-mercaptoethanol and Cysteine Supplementation of Culture Medium on Development of One-cell and Morula Stage Mouse Embryos

Contents Influence of β-mercaptoethanol (β-ME) in the presence or absence of ethylenediaminetetraacetic acid (EDTA) and cysteine (CYS) on the development of early (one-cell) and late (morula) stage mouse embryos was evaluated in two consecutive experiments conducted according to 2 × 2 × 2 factorial design. In experiment 1, one-cell stage embryos were cultured in one of the eight factorial WM (Whitten's medium) containing 3 mg/ml bovine serum albumin (BSA) for 120 h to reach the blastocyst stage. No interaction was observed among EDTA (0.1 mm), β-ME (50 µm) and CYS (50 µm). EDTA was the main agent supporting development of one-cell stage embryos to blastocyst stage (p < 0.01). The β-ME and CYS had no influence on the development of one-cell embryos to the blastocyst stage. In experiment 2, one-cell stage embryos were cultured in WM containing 3 mg/ml BSA and 0.1 mm EDTA for 72 h. Embryos that developed to the morula stage were selected and further cultured for 48 h in one of the eight experimentally altered WM with 3 mg/ml BSA containing β-ME (50 µm) and/or CYS (50 µm) in the presence or absence of EDTA (0.1 mm). The β-ME supplementation of the culture medium improved development of morulae to blastocyst stage (p < 0.05). No interaction was detected among the additives. These data indicate that some factors other than the proposed mechanism of action of β-ME may be involved in its growth promoting activity on embryo development