Chronic exposure to ambient particulate matter alters cardiac gene expression patterns and markers of oxidative stress in rats. Rattus norvegicus

Exposure to ambient particulate matter (PM) significantly increases cardiovascular morbidity and mortality in the general population. We hypothesized that some components of PM can affect the gene expression patterns in the hearts of rats exposed for 3 months to filtered air (FA), coarse (CP; 2.5 1.5 (for both up- and downregulated genes), we found three genes in the CP and nine genes in the UFP groups with significantly changed expression, compared with FA. No significant changes in gene expression patterns were observed in the FP group. In the UFP group, thioredoxin-interacting protein (Txnip), a negative regulator of an antioxidant enzyme thioredoxin, and cytochrome P450 (Cyp2e1), an enzyme involved in the metabolism of foreign substances, demonstrated significant up-regulation (fold ratios 1.79 and 1.57, respectively, with false discovery rate, FDR 0.05) and significant increase in the Cyp2e1 expression (fold ratio 1.79, FDR 1.5 for both up- and downregulated genes) were selected. The gene list was further filtered by FDR (false discovery rate) of <0.05 and <0.25, which indicate that no more than 5% and 25% of all listed genes are false positives (an assumption that is not offered by a traditional p value-based analysis).