Abstract

Fine particulate matter (PM2.5) emitted by wood smoke is a significant environmental pollutant associated with oxidative stress and hypoxia. These conditions can disrupt placental function by altering the expression of key nutrient transporters, such as glucose transporter 1 (GLUT1) and sodium-dependent vitamin C transporter 2 (SVCT2), which are essential for fetal development. This study evaluates the effects of pregestational and gestational exposure to PM2.5 on GLUT1 and SVCT2 expression in the rat placenta. Pregnant Sprague-Dawley rats were exposed to either filtered air (FA) or non-filtered air (NFA) containing PM2.5 from wood combustion in a controlled exposure system. Four experimental groups were established: FA/FA (control), FA/NFA (gestational exposure), NFA/FA (pregestational exposure), and NFA/NFA (continuous exposure). Immunofluorescence and confocal microscopy were used to quantify the expression of GLUT1 and SVCT2 in the placental labyrinth zone. Statistical analyses were performed using Kruskal-Wallis and post hoc Dunn's test (p < 0.05). Gestational exposure to PM2.5 (FA/NFA) significantly reduced GLUT1 and SVCT2 expression, compromising glucose transport and antioxidant protection in the placenta. Pregestational exposure (NFA/FA) induced a compensatory increase in SVCT2 expression, suggesting an adaptive response to oxidative stress. Continuous exposure (NFA/NFA) resulted in GLUT1 redistribution within the syncytiotrophoblast and decreased membrane localization, potentially impairing glucose uptake. PM2.5 exposure disrupts the expression and localization of GLUT1 and SVCT2 in the placenta, with differential effects depending on the timing of exposure. The gestational phase appears to be particularly vulnerable, as reduced GLUT1 and SVCT2 levels may impair fetal nutrition and antioxidant defense. These findings underscore the need for preventive measures to mitigate air pollution-related risks during pregnancy.