Abstract
Disclosure: V.M. Nascimento: None. I.S. Andrade: None. C.B. Andrade: None. R.S. Alves: None. R.P. Sousa: None. A.C. Valim: None. L.S. Dias: None. K.N. Fontes: None. I.F. Miranda: None. S.A. Coelho: None. L.B. Arruda: None. R.S. Fortunato: None. T.M. Ortiga-Carvalho: None. The placenta is a maternal-fetal organ with nutritional, exchanging, hormonal and protecting functions that are vital for fetal growth and development during gestation. However, these functions can be disturbed by vertically transmitted pathogens such as Zika virus (ZIKV). In 2015, ZIKV was responsible for an increasing number of newborns with congenital abnormalities in Brazil, known as Congenital Zika Syndrome (CZS). Nonetheless, the extension of ZIKV infection in the placenta, leading to CZS, is still unclear. It is known that ZIKV causes oxidative stress in trophoblasts. However, no one has ever studied placental oxidative stress caused by ZIKV infection in vivo. Here, we investigated whether maternal ZIKV infection could cause sex-specific oxidative stress in murine placenta. At gestational day (GD)12.5, pregnant mice (C57BL/6; 8-12 weeks old) were infected with ZIKV-BRPE243 (5x107 PFU; ZIKV group, n=22) or Mock (supernatants of noninfected C6/36 cells; control group, n=28). At GD18.5, c-section was performed and maternal spleens, placentas, fetuses and fetal brains were collected. We measured placental carbonylated protein levels (n=7), by 2D OxyBlot, nitrotyrosine residues (n=5), by immunohistochemistry, reduced thiol content (n=9), total superoxide dismutase (SOD; n=9) and total glutathione peroxidase (GPx; n=9) activities, by spectrophotometry. Data were analyzed by unpaired Student’s t test and Two-Way ANOVA with Tukey’s post test and represented as mean±SEM. ZIKV infection increased maternal spleen weight (p<0.0001) and decreased both female (p=0.0429) and male (p=0.0171) placental weight. Although placental weights were affected by the infection, female and male fetal weight and fetal crown-rump length were not changed. Conversely, maternal ZIKV infection increased only female fetal brain weight (p=0.0028). Moreover, we found that ZIKV infection increased nitrotyrosine residues in the placental labyrinth region of both female (p<0.0001) and male (p=0.0007) fetuses. Meanwhile, nitrotyrosine residues were increased by the infection only in the placental junctional zone of female fetuses (p=0.0131). Although ZIKV increased this oxidative damage biomarker, placental carbonylated protein levels were not changed by the infection in both sexes. Also, reduced thiol content and total SOD and GPx activities were not affected. Together, our data show that maternal ZIKV infection caused oxidative stress in both placental regions of female and male fetuses, as we saw that ZIKV increased oxidative damage, although antioxidant defenses were not changed by the infection, at least at term (GD18.5). ZIKV infection may have disturbed placental growth, as we found that placental weight was decreased in both sexes. Moreover, we believe that the increase in the female fetal brain weight could be a suggestive feature of cerebral edema or hydrocephalus. Presentation: 6/2/2024