Decreased superoxide dismutase expression and increased concentrations of lipid peroxide and prostaglandin F-2 alpha in the decidua of failed pregnancy

To study the possible role of the superoxide radical and its scavenging sys tem in the decidua of early pregnancy, superoxide dismutase (SOD) values an d concentrations of lipid peroxide and prostaglandin F-2 alpha (PGF(2 alpha )) were analysed in the decidua obtained from normal pregnancy and failed p regnancy. Failed pregnancy was divided into two groups; spontaneous abortio n with or without vaginal bleeding. In the spontaneous abortion with vagina l bleeding, total SOD activities, Cu,Zn-SOD activities and Cu,Zn-SOD mRNA v alues in the decidua were significantly lower, and concentrations of lipid peroxide and PGF(2 alpha) were significantly higher, than those in the norm al pregnancy and the spontaneous abortion without vaginal bleeding. In cont rast, activities and mRNA values of Mn-SOD were significantly higher in the spontaneous abortion with vaginal bleeding than the other two groups. Ther e was no significant difference in all of these parameters between the norm al pregnancy and the spontaneous abortion without vaginal bleeding. In conc lusion, the decrease in Cu,Zn-SOD expression and the increase in lipid pero xide in the decidua could be involved in the termination of spontaneous abo rtion, mediated through the increase in PGF(2 alpha) synthesis. In other wo rds, Cu,Zn-SOD may contribute to the maintenance of pregnancy by preventing the accumulation of superoxide radicals that cause PGF(2 alpha) synthesis.