Abstract
Supplementing Whitten's medium with both activin A and superoxide dismutase (SOD), either of which singly has a beneficial effect, can enhance synergistically the development of 1-cell mouse embryos to the blastocyst stage in vitro. To release the 2-cell block and support embryonic development up to blastocysts, the lowest concentrations were 1.0 ng/ml and 2.5 ng/ml of activin A in CD-1 and DBA/2NJcl mice, respectively, and 300IU/ml of SOD in both strains. The percent-age of cultured embryos developing from the pronuclear stage to the 3-or 4-cell stage was signifi-cantly higher in media containing both supplements at the concentrations mentioned above than in media supplemented with either activin A or SOD. Pronuclear embryos developed to either moru-lae or blastocysts in the activin A plus SOD group at significantly higher proportions (p<0.01) than those in groups treated with activin A or SOD separately. The synergism between the 2 supple-ments for releasing 2-cell block indicates that the modes of action are different for activin A and SOD.
