Role of reactive oxygen species in diabetes-induced embryotoxicity: studies on pre-implantation mouse embryos cultured in serum from diabetic pregnant women.

Sera from diabetic patients or sera with high levels of diabetic metabolic products, were found to affect mouse and rat blastocysts. In the present study we examined the earliest developmental stages at which human diabetic serum will be lethal to mouse pre-implantation embryos, and whether reactive oxygen species (ROS) are involved in these diabetes-induced injuries. We cultured 2-4 cell-stage embryos and blastocysts in a medium containing 30 or 50% serum obtained from pregnant women with diabetes Type I, Type II and gestational diabetes (GDM) for 72 h. The development of the 2-4 cell-stage embryos was delayed when cultured in 30% diabetic serum, but the viability was impaired to a lesser extent. Viability was reduced in blastocysts cultured in 50% diabetic serum, but the development of the living embryos was not delayed. Cyclic voltametry measures the oxidation potential of the tissue and the concentration of antioxidants, thus reflecting the total antioxidative activity of the embryos. Pre-implantation embryos cultured in diabetic serum had a lower concentration of antioxidants than embryos cultured in non-diabetic serum. It seems, therefore, that diabetic metabolic factors may induce embryotoxicity in pre-implantation embryos through derangement of the antioxidant defense mechanism. A similar mechanism is suggested for the diabetes-induced teratogenicity in post-implantation embryos.