PM_2.5 caused ferroptosis in spermatocyte via overloading iron and disrupting redox homeostasis

Fine particulate matter (PM_2.5) has been reported to cause various types of damage to male reproductive system, but the research on the underlying mechanisms is still insufficient. This study attempted to explore the underlying mechanisms of this widely concerning environmental health problem through in vivo and in vitro exposure models. Significant pathological damage and abnormal mitochondria in spermatocytes were observed in the real-time PM_2.5 exposure animal model. In addition, significant alterations in key biomarkers of iron metabolism and ferroptosis were found in testis tissues. Notably decreased cell viability was found in vitro. Moreover, the ferroptosis pathway was significantly enriched in the transcriptome enrichment analysis. Subsequent experiments showed that the two core events of ferroptosis, iron overload and lipid peroxidation, occurred in spermatocytes after PM_2.5 treatment. Moreover, lipid metabolic genes (Acsl4 and Aloxe3) and the antioxidant gene Gpx4 were found to be key target genes of ferroptosis caused by PM_2.5 in spermatocytes. Importantly, further studies showed that the damaging effect could be reversed by the iron chelator deferoxamine mesylate (DFOM) and the lipid peroxidation inhibitor ferrostatin-1 (Fer-1), which further confirmed the role of ferroptosis in PM_2.5 toxicity. Our study revealed the vital role of ferroptosis in PM_2.5-induced male reproductive damage, providing novel insights into the air pollution-induced decrease in male fertility.