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Ureaplasma parvum infection alters the placental redox status and may contribute to spontaneous abortion: a
Fernanda Karoline A Freire1, Lara Fabiana L Malheiro2, Thiago M L Correia2
1Microbiology and Immunology Laboratory, Federal University of Bahia, Anísio Teixeira Campus, Vitória da Conquista, Bahia, Brazil.
Introduction:
This study aimed to investigate markers of oxidative stress in the placenta in the context of spontaneous abortion (SA) associated with Ureaplasma parvum infection.
Material & Methods:
Placental samples from 89 women with spontaneous abortion (SA) and 20 with full-term delivery (C) were analyzed based on U. parvum (UP) infection status. Tissues underwent oxidative/nitroxidative stress, antioxidant, gene expression, and immunohistochemical analyses, with data integrated via PCA. After Kolmogorov-Smirnov testing, 2x2 comparisons were performed using Student's t-test or Mann-Whitney, as appropriate.
Results:
The results indicated oxidative lesions, protein, and lipid damage. Infection in the SA group contributed to the reduction of thiobarbituric acid-reactive substances (p < 0.0001), an increase in protein carbonylation (p < 0.01) and nitrite levels (p < 0.01), and a tendency for elevated 8-OHdG (p > 0.05). It also increased superoxide dismutase (SOD) activity (p < 0.05) and the SOD/GPx ratio (p < 0.05) while reducing catalase (CAT) (p < 0.01), glutathione peroxidase (GPx) (p < 0.0001), the SOD/CAT ratio (p < 0.0001), and nuclear factor erythroid 2-related factor 2 immunostaining (p < 0.05). Gene expression analysis revealed that the SA group with UP infection showed increased Copper/zinc-SOD/CAT (p < 0.01) and Manganese-SOD/CAT (p < 0.01) ratios and decreased Copper/zinc-SOD/GPx (p < 0.05) and Manganese-SOD/GPx (p < 0.0001) ratios. In the PCA, samples from the SA groups with and without infection exhibited similarities, standing out for their higher concentrations of manganese, copper, and zinc.
Conclusion:
These findings suggest that U. parvum infection may result in a dynamic oxidative imbalance and significant variability in the placenta, which may, in turn, contribute to the development of SA.
