ANÁLISE DE MARCADORES DE ESTRESSE OXIDATIVO EM MEMBRANAS CORIOAMNIÓTICAS DE PARTOS PRÉ-TERMOS ACOMETIDAS PELA CORIOAMNIONITE HISTOLÓGICA

Abstract

Objective: The present work aims to evaluate the association between histological chorioamnionitis and the production of oxidative stress markers. Methodology: This is a prospective, observational and analytical study with a non-probabilistic sample consisting of 21 samples of chorioamniotic membranes from pregnant women affected by premature birth and admitted to the Maternal and Child Unit of the Hospital Universitário Lauro Wanderley (HULW). The histopathological analysis of the ovular membranes was performed by a single observer from the Anatomic Pathology Laboratory of HULW, without prior knowledge of the clinical information of the case and standardized according to the nomenclature proposed by Redline et al., 2003. Malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels were obtained from ovular membranes by total DNA extraction from these tissues, according to the technical standards available from the ILLUSTRA tissue & cells genomic-Prep kit Mini Spin followed by the quantification of their levels, established by the Highy Sensitive Check ELISA kit, carried out in the Immunopathology laboratory of the Botucatu Medical School, Universidade Estadual Paulista. The analysis of continuous variables was performed using the Student's t-statistic test and the analysis of categorical variables using the Fisher's Exact Test, adopting, as a significant difference, a p value < 0.05. Results: In the general composition of the sample, two comparative groups were formed. One group had membrane samples diagnosed with histological chorioamnionitis (CAM-H) grade 1 and another group with a diagnosis of CAM-H grade 2. In them, all births were premature. Pregnant women's age, body mass index (BMI), ethnicity and type of delivery were similar, with no statistical differences between their values. The median gestational age in the CAM-H grade 1 group was 33.8 weeks (min: 26.0 – max: 36.0) and in the CAM-H grade 2 group it was 28.0 weeks (min: 23.4 – max: 34.0) determining a statistical difference significant with p value = 0.01. Likewise, the weight of the newborn in the CAM-H grade 1 group had a median of 2152g (min: 760 – 2775), while in the CAM-H grade 2 group it was 1195g (min: 630 – max: 2750 ), whose p value was 0.03. The MDA levels differed significantly between the groups, p = 0.03, being observed in the CAM-H grade 1 group, the quantification of 0.13 ng/mL (± 0.03) and in the CAM-H grade group 2 is the value of 0.39 ng/ml (± 0.06). The levels of 8-OHdG were also statistically different between the groups, p value < 0.0001, obtaining in the CAM-H grade 1 group a quantification of 0.49 ng/mL (± 0.10) and in the group CAM-H grade 2 the value of 2.13 ng/mL (± 0.95). Conclusion: The data obtained in this study demonstrate that in the presence of the inflammatory process of the chorioamniotic membranes, arising from premature births, there is a possible pathophysiological pathway mediated by oxidative stress and this seems more accentuated the greater the inflammatory activity triggered by these fetal tissues.