Exploring the mechanism of lung injury induced by lunar dust simulant in rats based on metabolomic analysis.

Inflammatory response and oxidative stress are considered to be important mechanisms of lung injury induced by lunar dust. However, the pulmonary toxicological mechanism remains unclear. In the present study, Wistar rats were exposed to CLDS‐i 7 days/week, 4 h/day, for 4 weeks in the mouth and nose. Lung tissue samples were collected for histopathological analysis and ultra‐performance liquid chromatography–mass spectrometry analysis. Enzyme activities and expression levels of key metabolic enzymes were detected by biochemical analysis and real‐time PCR. The pathological features of lung tissue showed that CLDS‐i caused congestion and inflammation in the lungs, and the lung structure was severely damaged. Metabolomics analysis showed that 141 metabolites were significantly changed in the lung tissue of the CLDS‐i group compared with the control group. Combined with Kegg pathway analysis, it was found that the changes of amino acid metabolites were involved in these pathways, indicating that the simulated lunar dust exposure had the most obvious effect on amino acid metabolism in the lung tissue of rats. Real‐time PCR analysis showed that the mRNA expression of six key enzymes related to amino acid metabolism was changed, and the enzyme activities of these key enzymes were also changed, which were consistent with the results of qPCR. These results suggest that changes in amino acid metabolism may be closely related to the pathogenesis of lung injury induced by lunar dust, and amino acid metabolism may be a potential biomarker of lung diseases related to lunar dust exposure. [ABSTRACT FROM AUTHOR]