Effects of oxygen toxicity on early development of mouse embryos

Abstract

To examine the effects of oxygen toxicity on embryonic development, mouse pronuclear embryos were cultured under low oxygen conditions with or without superoxide dismutase (SOD), and the blastulation rate was compared with that of embryos cultured under standard conditions. The blastulation rate of mouse pronuclear embryos cultured under standard conditions was only 1.5% (2/131). This rate was increased significantly, to 28.5% (43/151), when the embryos were cultured under low oxygen conditions; and to 31.0% (35/113) when SOD (500 micrograms/ml) was added to the medium under standard conditions; the rate was increased to 75.2% (115/153) when the embryos were cultured under low oxygen conditions in the presence of SOD. The minimum effective concentration of SOD in the culture medium was 50 micrograms/ml under conditions of 5% O2. The blastulation rate was significantly decreased after 1-hr exposure of pronuclear embryos to room atmospheric oxygen concentration (20% O2), and subsequent culture under 5% O2 with SOD did not result in an improved blastulation rate. Culture with SOD under 5% O2 promoted the development of two-cell stage embryos to the blastocyst stage. When two-cell stage embryos were collected 48 hr after hCG and cultured for 66 hr, their blastulation rate was similar to that of embryos collected from mice 114 hr after hCG. These results suggested that embryonic development in vitro is greatly affected by atmospheric oxygen throughout the early embryonic stages and that this harmful effect can be prevented by culturing embryos under low oxygen conditions and in the presence of SOD.

Superoxide dismutase affects the viability of thawed European mouflon (Ovis g. musimon) semen and the heterologous fertilization using both IVF and intracytoplasmatic sperm injection

“…The presence of SOD has been found to be beneficial during in vitro maturation and fertilization of porcine oocytes (Park et al 1996), and it was also found to have beneficial effects on bovine embryonic development in vitro (Liu and Foote 1995). Moreover, several studies of mouse embryos (Noda et al 1991;Umaoka et al 1992;Chun et al 1994) indicate that the two-cell block occurring in vitro could be alleviated by protection against oxidative stress mediated by SOD action. On the other hand, Luvoni et al (1993) have observed that the addition of SOD from the time of oocyte collection to Day 8 of culture under 5% CO 2 in air improved the cleavage rate of in vitro-inseminated bovine oocytes, although not during further stages of development.…”

Improvement in bovine embryo production in vitro by glutathione-containing culture media

“…Several studies with mouse embryos (Noda et al, 1989Nonogaky et al, 1991;Umaoka et al, 1991Umaoka et al, , 1992Chun et al, 1994) indicate that the two-cell block occurring in vitro could be alleviated by protection against oxidative stress mediated via a potent scavenger of oxygen radicals, superoxide dismutase (SOD). Moreover, Legge and Sellens (1991) reported that when reduced glutathione (GSH) was added to a serum-free medium for the culture of mouse embryos, development to the morula or blastocyst stage was promoted, but neither SOD nor catalase had any effect on the embryonic development.…”

Immunohistochemical assessment of CuZn-superoxide dismutase in the human genital organs.

“…In addition, an additive effect of low oxygen and SOD on mouse embryo development has been demonstrated (48). These results suggest that mouse 2-cell block is due to damage to the embryos by oxygen radicals.…”