Endurance Training-Induced High Fitness Can Prevent Skeletal Muscle Mitochondria Damage During Short-term Fine Particulate Matter Exposure

PURPOSE: Exposure to fine particulate matter (PM2.5) is associated with damage to skeletal muscle mitochondria. However, effective methods to prevent PM2.5-induced skeletal muscle mitochondrial damage remain elusive. This study aims to explore whether endurance training can prevent the adverse effects of PM2.5 exposure to skeletal muscle mitochondria damage. METHODS: This study subjected 4-week-old male C57BL/6J mice to 12 weeks of sedentary/endurance training, followed by PM2.5 exposure or a control group for 3 consecutive days.After completion of all treatments, skeletal muscle tissue was collected 18 hours after the final PM2.5 exposure for analysis of mitochondrial morphological damage, biogenesis, dynamics, and antioxidant enzymes levels. RESULTS: The sedentary PM2.5-exposed group suffered extensive mitochondrial damage. Prior endurance training before PM2.5 exposure group exhibited higher levels of skeletal muscle antioxidant enzymes (SOD-2, catalase and GPx-4) and a high-level response of regulatory factors related to mitochondrial biogenesis (PGC-1α) and dynamics (Fis-1) following PM2.5 exposure, thereby preventing the accumulation of mitochondrial damage. CONCLUSIONS: Prior endurance training can prevent PM2.5 exposure-induced skeletal muscle mitochondrial alterations by enhancing the response of antioxidants, mitochondrial biogenesis, and dynamics.