Histological and stereological insights into renal and adrenal changes in pregnant rats exposed to wood smoke-derived PM2.5.

Air pollution, particularly fine particulate matter (PM2.5), is a global health issue affecting millions. In southern Chile, firewood used for heating exacerbates pollution, especially in winter. This study examines the impact of wood smoke-derived PM2.5 on kidney and adrenal gland morphology in pregnant rats. It evaluates chronic PM2.5 exposure effects during pregestational and gestational periods in Sprague-Dawley rats. Pregnant rats were exposed to PM2.5 in Temuco, a city with high wood smoke pollution. Filtered and unfiltered air chambers simulated different exposure conditions. Histological and stereological analyses were conducted on rat kidneys and adrenal glands using systematic sampling and STEPanizer software. Findings showed significant changes in renal and adrenal morphology due to PM2.5 exposure. In the kidney, variations were observed in glomerular compaction, proximal convoluted tubules, and medullary rays. In the adrenal gland, the zona fasciculata showed decreased acidophilia and lipid content, reduced cytoplasmic homogeneity, and the appearance of empty spaces. These effects were more pronounced in rats exposed to unfiltered air during both pregestational and gestational periods. Wood smoke-derived PM2.5 exposure significantly impacts kidney and adrenal morphology in pregnant rats, emphasizing the need for strategies to reduce environmental pollutant exposure during critical developmental periods to protect maternal-fetal health.