Involvement of superoxide radicals in the mouse two-cell block.
The effect of oxygen toxicity on the development of mammalian embryos was assessed by the use of superoxide dismutase (SOD), a potent scavenger of superoxide radicals. Mouse pronuclear embryos recovered 17 h after human chorionic gonadotropin (hCG) were cultured in medium BWW at 37 degrees C under an atmosphere of 5% CO2 in air. Culture of mouse pronuclear embryos in the presence of Cu.Zn-SOD (500 micrograms/ml) significantly increased the blastulation rate (44.6%) when compared with the control culture system (4.2%). Essentially the same effects were observed in SOD containing either Mn or Fe in the catalytic center. Heat treatment of the SOD preparation, and the addition of anti-SOD antibodies to the culture medium, significantly reduced the attenuation of the two-cell block by SOD, indicating that this effect is SOD dependent. SOD activity was detected in rabbit oviduct fluid (3.675 +/- 3.084 mIU/mg protein) by electron spin resonance. These results suggest that active oxygen is involved in the two-cell block phenomenon in mouse embryos exposed to air and that SOD in the oviduct may play an important role in the protection of embryos from superoxide radicals.
Noda
Y
Y
Department of Gynecology and Obstetrics, Faculty of Medicine, Kyoto University, Japan.
Matsumoto
H
H
Umaoka
Y
Y
Tatsumi
K
K
Kishi
J
J
Mori
T
T
D000818:Animals; D046508:Culture Techniques; D005314:Embryonic and Fetal Development; D005260:Female; D051379:Mice; D010100:Oxygen / Q000633:toxicity*; D011817:Rabbits; D013482:Superoxide Dismutase / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism*
D013481:Superoxides; D013482:Superoxide Dismutase; D010100:Oxygen