Involvement of superoxide radicals in the mouse two‐cell block

Abstract

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.

The effect of alpha lipoic acid on the developmental competence of mouse isolated preantral follicles

“…It has been shown that in the in vivo condition, ROS production is a usual itinerary in the mitochondrial respiratory chain which is equilibrated by antioxidant defense systems of cells [4,5]. Increased ROS production occurs in the in vitro milieu [18], which is in agreement with results of this study that showed an accrual of ROS formation in cultured preanral follicles up to 96 h. It has been founded that fortifying of the culture medium with antioxidants led to improved culture condition [25,[37][38][39] It has been recommended that ALA beside its main role as a coenzyme of various enzymes like pyruvate dehydrogenase complex that catalyses the utilization of pyruvate in mouse oocytes and follicles [28,29] also acts as a potent antioxidant and able to react directly with ROS [17,36,51]. These observations are in agreement with our data, which showed, ROS levels during IVM of follicles in the presence of ALA were significantly decreased in comparison to the control groups.…”

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

“…They have suggested that pronuclear formation under physiological conditions is protected from oxidative stress in SOD-rich oviduct fluid. The effectiveness of SOD on pronucleus formation in mouse pronuclear stage embryos has also been suggested by Noda et al (1991), who demonstrated that SOD attenuates the two-cell block in mouse embryos cultured in vitro when added to culture medium, allowing the embryos to undergo cleavage past the two-cell block.…”

“…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.…”

Effect of vitamin A supplementation at different gaseous environments on in vitro development of pre-implantation sheep embryos to the blastocyst stage

“…These include developmental blocks at the twocell stage in mice (Nasr-Esfahani and Johnson, 1991), four-to eight-cell stage in bovine (Camous et al, 1984), and sixteen-cell stage in goat (Sakkas et al, 1989), etc. Although the molecular mechanisms underlying such developmental blocks are yet to be deciphered, ROSs are also presumed to have a role in the same (Noda et al, 1991). Hajializadeh et al (2008) observed that retinoic acid supplementation to culture media helps murine embryos overcome the two-cell block.…”