Inflammatory response in rat lungs with recurrent exposure to welding fumes: a transcriptomic approach

As chronic exposure to welding fumes causes pulmonary diseases, such as pneumoconiosis, public concern has increased regarding continued exposure to these hazardous gases in the workplace. In a previous study, the inflammatory response to welding fume exposure was analysed in rat lungs in the case of recurrent exposure and recovery periods. Thus using lung samples, well-annotated by histological observation and biochemical analysis, this study examines the gene expression profiles to identify phenotype-anchored genes corresponding to lung inflammation and the repair phenomenon after recurrent welding fume exposure. Seven genes (Mmp12, Cd5l, LOC50101, LOC69183, Spp1, and Slc26a4) were found to be significantly up-regulated according to the severity of the lung injury. In addition, the transcription and translation of Trem2, which was up-regulated in response to the repair process, were validated using a real-time polymerase chain reaction, Western blotting, and immunohistochemistry. The differentially expressed genes in the exposure and recovery groups were also classified using k-means and hierarchical clustering, plus their toxicological function and canonical pathways were further analysed using Ingenuity Pathways Analysis Software. As a result, this comprehensive and integrative analysis of the transcriptional changes that occur during repeated exposure provides important information on the inflammation and repair processes after welding-fume-induced lung injury.