肺
纤维化
肺纤维化
病理
医学
羟脯氨酸
支气管肺泡灌洗
免疫学
内科学
作者
Naresh Singh,Naveen Arora
标识
DOI:10.1016/j.scitotenv.2021.150623
摘要
Epidemiological studies suggest increased risk of lung cancer associated with diesel exhaust (DE) exposure. However, DE-induced lung fibrosis may lead to cancer and needs investigation.To study the mechanism involved in the initiation of DE- induced lung fibrosis.C57BL/6 mice were exposed to DE for 30 min/day for 5 days/weeks for 8 weeks. Pulmonary function test was performed to measure lung function. Mice were euthanized to collect BALF, blood, and lung tissue. BALF was used for cell count and cytokine analysis. Lung tissue slides were stained to examine structural integrity. RNA from lung tissue was used for RT-PCR. Immunoblots were performed to study fibrosis and EMT pathway.Mice exposed to DE increase lung resistance and tissue elastance with decrease in inspiratory capacity (p < 0.05) suggesting lung function impairment. BALF showed significantly increased macrophages, neutrophils and monocytes (p < 0.01). Additionally, there was an increase in inflammation and alveolar wall thickening in lungs (p < 0.01) correlates with cellular infiltration. Macrophages had black soot deposition in lung tissue of DE exposed mice. Lung section staining revealed increase in mucus producing goblet cells for clearance of soot in lung. DE exposed lung showed increased collagen deposition and hydroxyproline residue (p < 0.01). Repetitive exposure of DE in mice lead to tissue remodeling in lung, demonstrated by fibrotic foci and smooth muscles. A significant increase in α-SMA and fibronectin (p < 0.05) in lung indicate progression of pulmonary fibrosis. TGF-β/Smad3 signaling was activated with increase in P-smad3 expression in DE exposed mice. Decreased expression of E-cadherin and increased vimentin (p < 0.05) in lungs of DE exposed mice indicate epithelial to mesenchymal transition.DE exposure to mice induced lung injury and pulmonary fibrosis thereby remodeling tissue. The study demonstrates TGF-β/SMAD3 pathway involvement with an activation of EMT in DE exposed mice.
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