BIOCHEMICAL MARKERS OF MISCARRIAGE ASSOCIATED WITH THE INTRAPLACENTAL ACCUMULATION OF 137Cs.

Unlabelled: The impact of the environment on human health in modern conditions cannot be underestimated. The study of thepathogenesis of disease is impossible without establishing the factors of destabilization of biological membranes.The article highlighted the problem of lipid peroxidation and antioxidant defense associated with the accumulationof radiocesium in the placenta.

Objective: to determine the biochemical markers of miscarriage associated with the accumulation of 137Cs in the placenta.

Materials And Methods: According to the research design, pregnant women were divided into groups. Group 1included 153 women with reproductive losses in anamnesis and signs of termination of the current pregnancy.Group 2 (control) included 30 women with an uncomplicated pregnancy and medical history. The women of Group1 were divided into subgroups: 1a - in which the pregnancy ended with timely delivery, despite threatening signsof termination; 1b - pregnancy ended in late premature birth; 1c - pregnancy ended in early premature birth.Accumulation of 137Cs with different activity was detected in the placentas of both groups by β-spectrometry. Theeffect of 137Cs is the activation of free radical processes. The strength of oxidative stress was studied by the contentof diene conjugates (DC) and malondialdehyde (MDA) in the blood. The antioxidant capacity was determined by theactivity of catalase, glutathione-S-transferase, and superoxide dismutase (SOD). Biochemical studies were performed using a spectrophotometer «Specol-11» (Germany).

Results: The increase of DC in the 1st trimester by 2.25 times, in the 2nd and 3rd trimesters by 1.25 and 1.5 times indicates the activation of free radical reactions. The trigger for late preterm births is an increase in MDA in the 1sttrimester by 17.4 %. An increase in MDA by 23.4 % in the 1st trimester indicates the risk of early premature birth andintrauterine death of the fetus. A decrease in the activity of SOD in the 1st trimester by 13.0 % can be a predictor ofpremature birth. Decreased activity of SOD by 18.2 % in the 1st trimester indicates decompensation of adaptationmechanisms. As a result of oxidative stress caused by the accumulation of 137Cs in the placenta, the activity of GSTdecreases almost 2 times. In the 1st trimester, catalase activity in the blood of pregnant women of the 1b and 1csubgroups was reduced by 39.2 % and 44.9 %. The dynamics of catalase in the 2nd trimester indicate the activationof adaptive reactions. After 25 weeks, catalase activity is inhibited in pregnant women of subgroups 1b and 1c dueto depletion of antioxidant protection mechanisms. The activity of 137Cs in the placenta above 4.5 Bq/kg causesdepletion of antioxidant mechanisms, which is confirmed by persistent inhibition of catalase and SOD activityagainst the background of high levels of DC and MDA in the blood. Critical for pregnancy is the activity of 137Cs inthe placenta above 10.4 Bq/kg.

Conclusions: The accumulation of 137Cs in the placenta leads to the activation of lipid peroxidation beyond thecapacity of the antioxidant system. Extreme effects depend on the 137Cs activity and placenta compensatory ability.Indicators of MDA, DC, SOD, and catalase are prognostic regarding the power of oxidative stress and pregnancyscenarios.