Addition of superoxide dismutase and catalase does not necessarily overcome developmental retardation of one-cell mouse embryos during in-vitro culture

Abstract

There is evidence that developmental blocks observed in mouse embryos during culture in vitro may be the result of free radical-induced cellular dysfunction. We have further investigated this possibility by examining the effects of 5% O2 and the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), on mouse 1-cell embryo development. The results demonstrate that development of CF-1 strain embryos is enhanced by incubating in 5% CO2, 5% O2, 90% N2 (5/5/90) compared with 5% CO2 in air (5/air) (P < 0.01) and by culturing in the presence of other embryos. Superoxide dismutase significantly improved embryonic development (35 +/- 5% v. 17 +/- 4% morulae/blastocysts, P < 0.001) at a concentration of 100 units mL-1 when embryos were gassed under 5/5/90. At a concentration of 1000 units mL-1, SOD was detrimental to development (P < 0.001). Injection of SOD and/or CAT into embryos had not effect on development. Development has also been examined in four strains of mice (CF-1, Quackenbush (random-bred strains), Balb-C (inbred) and the F1 hybrid of CBA x C57B1) in the presence or absence of 100 units SOD mL-1 and 1000 units CAT mL-1. Embryonic development was markedly different among the four strains examined, with F1 hybrid > Balb-C (P < 0.001), Balb-C > CF-1 (P < 0.05) and Quackenbush embryos performing very poorly compared with the embryos of the other three strains (P < 0.001).