Specific features of redox reactions in the blood of women with physiological or complicated pregnancy

Much attention is now paid to investigations of of the processes of oxidative stress in pregnant women. An imbalance between the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) and the function of the antioxidant system can lead to cell and tissue structural damage, by inducing various pathologic processes. During pregnancy, in both its normal and abnormal course, the total level of oxidative stress increases. In abnormal pregnancy, the formed ROS and RNS, which trigger a cascade of free radical reactions leading to the formation of lipid peroxidation products, such as malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and nitrosyl derivatives (NDs), which serve as objective indicators of oxidative damage to proteins. Objective. To determine the level of the products of ROS, RNS, and antioxidant enzymes in the peripheral blood of pregnant women in different trimesters in the presence of preterm labor (PL), preeclampsia (PE), fetal growth restriction (FGR), and physiological pregnancy (PP). Subjects and methods. The course of pregnancy and the outcomes of labor were analyzed in 131 women from 4 groups. The level of oxidative stress was estimated from the blood concentrations of lipid peroxidation products, such as MDA and 4-HNE, protein peroxidation products, such as NDs, the content of the antioxidant enzymes glutathione peroxidase and superoxide dismutase, and the activity of catalase. Results. In physiological pregnancy, the levels of MDA and peroxynitrite adducts significantly increased. The PL group showed no significant differences in MDA levels between the trimesters. In this group, the level of NDs increased during the second trimester. The PE group displayed increased oxidative stress with pregnancy progression. In this group, the level of NDs rose in the second trimester. In the FGR group, the level of MDA increased with pregnancy progression in the presence of lower concentrations of NDs in the second trimester and their elevation in the third trimester. Comparison of the PL and PE groups with the PP group revealed significant increases in NDs and 4-HNE and decreases in glutathione peroxidase in the PL group and catalase activity in the PE activity. On the contrary, the catalase activity was higher in the FGR group than that in the PP group. Conclusion. The investigations confirmed increased oxidative stress levels during physiological pregnancy. The women with PE and those with PR were observed to have elevated blood levels of oxidative stress products in the presence of attenuation of the antioxidant systems. On the contrary, the women with FGR had enhanced activity of the antioxidant enzyme catalase, with a decline in NDs in the second trimester and its dramatic rise in the third trimester. The findings suggest that it is necessary to continue investigations of oxidative stress and activity of the antioxidant enzymes in both women with physiological pregnancy and those with abnormal pregnancy to create a shared understanding of normal and abnormal reactions.

preterm labor, preeclampsia, fetal growth restriction, reactive nitrogen species, malondialdehyde, peroxynitrite, catalase, superoxide dismutase, glutathione peroxidase