Induced preterm birth: evaluation of oxidative status, matrix metalloproteinases and their tissue inhibitors in amniotic fluid

Background: Hypoxic brain injury is the most common pathology in newborns. New criteria of viability and progress of perinatal technologies results in high neurological morbidity of surviving very early preterm infants. The aim of the study: To assess the level of oxidative stress, the activity of the system of matrix metalloproteinases (MMP-1 and MMP-9) and their tissue inhibitor (TIMP-1) in the amniotic fluid of low birth weight premature newborns after abdominal delivery. Materials and methods: The study included 142 women, 102 of whom were delivered by caesarian section within 28-33.6 weeks of gestation because of severe obstetric and/or perinatal complications (main group). The comparison group comprised 30 patients with term abdominal delivery, for obstetric indications. In 32 women of the main group and 30 of the comparison group the concentration of thiobarbitate-reactive products (TBRP) in amniotic fluid was determined by the photometric method on the KFC-3 spectrophotometer at 532 nm wavelength by changing the optical density, due to the coloring complex of the malone dialdehyde (MDA) with thiobarbitic acid Оригинальная статья Original article Научные результаты биомедицинских исследований. 2021;7(1):86-95 Research Results in Biomedicine. 2021;7(1):86-95 88 in a ratio of 1:2. The concentrations of matrix metalloprothyinasis and their tissue inhibitors were determined by immunoformation with the vertical photometer Multiscan at 450 nm wavelength. Results: The main indications for induced abdominal delivery are severe pre-eclampsia (38.2%), progress of placental insufficiency (24.5%), placental abruption (17.6%). In premature newborns, severe cerebral ischemia (p<0.05) is more commonly diagnosed after delivery induced for progressive fetal hypoxia (48.9%), and placental abruption (26.7%), while mild/medium cerebral ischemia is diagnosed after delivery for severe pre-eclampsia (54.4%). In the amniotic fluid of premature infants taken immediately after delivery, the concentration of TBRP, MMP-9, and the MMP/TIMMP-1 level was significantly higher and the TIMP-1 level was lower than that in newborns after term abdominal birth. Conclusion: The obtained results demonstrate that premature infants, delivered by caesarian section for maternal indications, underwent antenatal hypoxia induced by lifethreatening situations in the functional system «mother-placenta-fetus», which is confirmed by the presence of oxidative stress, the high activity of the enzymes destroying collagen type IV and low level of tissue inhibitors of matrix metalloprothyinasis.