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

PURPOSE: Exposure to fine particulate matter (PM<sub>2.5</sub>) is associated with damage to skeletal muscle mitochondria. However, effective methods to prevent PM<sub>2.5</sub>-induced skeletal muscle mitochondrial damage remain elusive. This study aims to explore whether endurance training can prevent the adverse effects of PM<sub>2.5</sub> 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 PM<sub>2.5</sub> exposure or a control group for 3 consecutive days. After completion of all treatments, skeletal muscle tissue was collected 18 hours after the final PM<sub>2.5</sub> exposure for analysis of mitochondrial morphological damage, biogenesis, dynamics, and antioxidant enzymes levels.RESULTS: The sedentary PM<sub>2.5</sub>-exposed group suffered extensive mitochondrial damage. Prior endurance training before PM<sub>2.5</sub> 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 PM<sub>2.5</sub> exposure, thereby preventing the accumulation of mitochondrial damage.CONCLUSIONS: Prior endurance training can prevent PM<sub>2.5</sub> exposure-induced skeletal muscle mitochondrial alterations by enhancing the response of antioxidants, mitochondrial biogenesis, and dynamics.