PFOS-induced mitochondrial ROS impairs male reproductive function by suppressing FTO-dependent m

Perfluorooctanesulfonic acid (PFOS), a persistent per- and polyfluoroalkyl substance, has been associated with male reproductive toxicity, but the underlying molecular mechanisms remain incompletely defined. Here, we show that chronic exposure to environmentally relevant doses of PFOS caused dose-dependent testicular injury and spermatogenic dysfunction in mice, as indicated by reduced testis weight, disrupted seminiferous tubule architecture, and impaired sperm quality. Transcriptomic profiling revealed marked enrichment of pathways related to oxidative stress, mitochondrial dysfunction, and reproductive regulation. Mechanistically, PFOS increased mitochondrial reactive oxygen species (ROS) production in GC-2 spermatocyte cells, leading to mitochondrial membrane potential collapse, lipid peroxidation, and depletion of antioxidant defenses. Pharmacological scavenging of mitochondrial ROS with Mito-TEMPO attenuated PFOS-induced mitochondrial injury in vitro and improved testicular damage and sperm quality in vivo. We further found that PFOS suppressed the RNA demethylase fat mass and obesity-associated protein (FTO) and promoted its ROS-dependent redistribution from the nucleus to mitochondria, resulting in global N6-methyladenosine (m