Impact of Maternal Exposure to Wood Smoke Pollution on Fetal Lung Morphology in a Rat Model

Abstract

Residential heating with wood is an important source of ambient air pollution. Evidence links air pollution to serious health effects such as respiratory and cardiovascular mortality and morbidity. We hypothesized that prenatal exposure to wood smoke pollution causes morphological changes in the development of the rat lung, leading to altered lung structure and function during later life. We presumed that analysis of the fetal lung stereology provides novel insights into the underlying processes mediating particulate matter associated developmental changes and damage. The objective of the study was to investigate the effects of exposure during gestational period to wood smoke pollution on lung fetal morphology. To test this, pregnant rats were exposed during pregestational and gestational periods to wood smoke pollution. Complete lungs samples were obtained from 24 fetus from healthy female G3 rats subjected to cesarean at 19 days post-fecundation. The lungs were prepared for histological and stereological analysis. The volume fraction of terminal bronchioles V V [tb, lung] and volume fraction of parenchyma V V [par, lung], surface density of terminal bronchioles S V [tb, lung] as well as numerical density of bronchiolar exocrinocytes N A [ec,lung] were calculated by light microscopy. Statistical analysis detected significant differences between groups in volume density V V [tb, lung; %] (p=0.0012) and surface density S V [tb, lung; mm 2 /mm 3 ] (p<0.0001) of the terminal bronchioles. However, it did not show differences between groups in the stereological parameter volume density V V [par, lung; %] (p=0.0838) and numerical density of bronchiolar exocrinocytes N A [ec,lung; nº/mm 2 ] (p=0.0705). The analysis of the evidence obtained indicates that exposure to environmental pollution was affects lung maturation, and particularly the proportion and area of terminal bronchioles in the fetal lung. In conclusion, maternal exposure to wood smoke pollution during pregnancy was associated with a decrease in the lower conducting airways of lungs, which, according to urban pollution studies, could be related to early childhood lower respiratory illness. The public health implications of this study are that reducing or avoiding exposure to wood smoke is important before and during pregnancy.

Developmental Programming in Animal Models: Critical Evidence of Current Environmental Negative Changes

“…In a study with pregnant rats, exposure to wood smoke pollution caused a decrease in the conducting airways of lungs. According to urban pollution studies, exposure to pollution could be associated with early childhood lower respiratory illness [166]. Another study in rats exposed to fine particulate matter (PM2.5) and gaseous pollutants during pregnancy showed behavioral deficits in male offspring at 21 days of life, including increased repetitive behavior, poor social interaction, and inability to differentiate social novelty [122].…”

Distribution of Calcitonin Gene-Related Peptide and Vascular Endothelial Growth Factor in the Mouse Lung at the Embryonic and Postnatal Stages

“…The wood smoke pollution during pregnancy in a rat model was effect to the terminal bronchioles in the fetal rat lung (Salinas et al, 2020). Calcitonin gene-related peptide (CGRP) such as stress marker was expressed in the lung during E11-E15 (Wuenschell et al, 1996).…”