PECULIARITIES OF THE FORMATION OF THE FUNCTIONAL SYSTEM "MOTHER- PLACENTA-FETUS" BY THE INFLUENCE OF SMALL DOSES OF RADIATION
Authors: Zhyvetska-Denysova A. , Vorobiova I. , Skrypchenko N. , Tolkach S. , Rudakova N. , Bondarenko Y. , Stryzhak S. 
Published: February 2023

Introduction. 137Cs ecosystem pollution is a source of radiation for humans. Undifferentiated cells capable of rapid division are the most vulnerable to ionizing radiation. Therefore, the fetoplacental and immune systems should be expected powerful responce to ionizing radiation. The functional capacity of the placenta determines pregnancy scenarios.Aim: to study the features of the formation of the fetoplacental system under the influence of low doses of radiation. Materials and methods. Pregnant women were in two groups, according to the design. The main (1) group included 60 women with reproductive losses in their history and a threat of termination to the current pregnancy, control (2) group consisted of 30 women with a physiological course of pregnancy and an uncomplicated anamnesis. The found incorporation of 137Cs in the placentas of the women of the studied groups was on β-spectrometry. The nature of placental damage was studied using the pathomorphological examination. The expressions of vimentin and CEA were studied in the structures of the placenta using immunohistochemistry. The effects of radiation on the functional system "mother-placenta-fetus" was determined in immunological, hormonal, biochemical, and bacteriological studies.The study was approved by the Medical Ethics Commission of the State Institution "Institute of Pediatrics, Obstetrics and Gynecology named after Academician O. M. Lukyanova of the National Academy of Medical Sciences of Ukraine" (Protocol No. 3 of 07.06.2017). The results were statistically processed on a PC using Microsoft Excel-2016 using Fisher's angular transformation criterion. Differences in comparative values are considered probable if p < 0.05 (probability index more than 95%).The research was carried out as a fragment of the research work of the State Institution "Institute of Pediatrics, Obstetrics and Gynecology named after Academician O.M. Lukyanova of the National Academy of Medical Sciences of Ukraine" "To develop the latest and improve existing technologies for the diagnosis, prevention and treatment of premature abortion in women with miscarriage, taking into account the placenta passport" (2018-2020). Code ВН.20.00.02.18, state registration number 0118U000039, КПКВ 6561040.Research results. According to the results, chronic radiation stress plays a decisive role in the multifactorial nature of placental dysfunction and antenatal losses. Activity up to 1.0 Bq/kg of 137Cs does not affect the course of gestation. The compensatory capacity of the placenta remains preserved at the accumulation of 1.1 to 4.4 Bq / kg of 137Cs. It is possible to prolong the pregnancy until term delivery. As a result of exposure to 4.5-10.4 Bq/kg of 137Cs, the stroma of the maternal surface of the placentas is damaged. At the same time, the pregnancy is terminated prematurely, at 28-36 weeks + 6 days, but thanks to the preservation of compensatory reactions in the placenta, the children are born alive. Accumulation in placentas of more than 10.4 Bq/kg of 137Cs is a probable factor in antenatal death of the fetus and early premature birth, as both maternal and fetal structures of the placenta are damaged.Conclusions. Internal irradiation by incorporated 137Cs damages the architecture of the placenta, which complicates the course of gestation. Extreme effects depend on the volumetric activity incorporating 137Cs and compensatory placental properties. The placental accumulation of 4.5 to10.4 Bq / kg of 137Cs triggers premature labor. Accumulation in the placenta of more than 10.4 Bq / kg 137Cs is a probable factor in antenatal fetal death and premature birth. An imbalance of steroid hormones and peroxide hemostasis system are predictors of placental dysfunction and termination of pregnancy. Expression of vimentin is a marker of placental destruction by internal exposure to radionuclides. Expression of CEA is a marker of premature birth and the antenatal death of the fetus.