Pregestational and Gestational Exposure to Wood Smoke-Derived PM_2.5 Is Associated with Structural Remodeling of the...

Chronic exposure to fine particulate matter (PM_2.5) derived from wood combustion represents a major environmental health burden, particularly during pregnancy. However, the impact of pregestational and gestational (PM_2.5) exposure on the maternal great vasculature remains largely unexplored. This study evaluates the effects of wood smoke-derived (PM_2.5) on the structural architecture of the maternal aortic arch and associated hemodynamic changes during pregnancy in second-generation Sprague-Dawley rats. Animals were allocated into four groups (n = 12) according to filtered (FA) or non-filtered air (NFA) exposure during pregestational and gestational periods: FA/FA, FA/NFA, NFA/FA, and NFA/NFA. Morphometric analysis revealed significant reductions in tunica media (p = 0.0251) and adventitia thickness (p = 0.0014) in exposed groups, without changes in integrated optical density, suggesting alterations in elastic matrix organization without evidence of net mass loss. Histological analysis supported exposure-dependent structural heterogeneity, including elastic lamellae fragmentation and extracellular matrix disorganization. Each exposed group exhibited a distinct systolic blood pressure trajectory across gestation, with FA/NFA reaching the highest values at day 18 (151.0 ± 17.0 mmHg) and NFA/FA displaying sustained elevations despite gestational low-exposure conditions. Principal component analysis (49.2% explained variance) revealed a structured multivariate distribution of vascular and hemodynamic variables across exposure conditions, consistent with an exposure-window-dependent pattern. These findings suggest that (PM_2.5) exposure is associated with coordinated structural and hemodynamic changes in the aortic arch and support the hypothesis that the pregestational period may represent a window of increased susceptibility.