Aim: Reactive oxygen species (ROS) are generated as by-products of cellular metabolism.When cellular production of ROS overwhelms its antioxidant capacity, damage to cellular macromolecules may ensue and finally let to muscle damage and its function decrease.Recent studies have also implicated that ROS affect mitochondrial biogenesis, morphology, and function.Their beneficial effects are likely mediated via the upregulation of transcriptional regulators such as peroxisome proliferator-activated receptor co-activator 1 a (PGC-1a).Here, we tested whether H2O2 induced by exercise could increase the expression of PGC-1a in skeletal muscle.Method:All BL6 mice were housed in specific-pathogen free animal care facilities and kept under a 12 h light/12 hr dark cycle with free access to food and water.A total of 25 mice were used in the study.All mice were divided into 4 groups: Wild type mice(WT, N =5) ,AAV-Catalase injected mice(C ,N =5), exercise mice(E), exercise and AAV-Catalase injected mice(CE).The exercise protocol consisted of treadmill running with 5°incline, 16 m/min, 1h/time.Facial vein injection was performed in 2-day-old BL6 mice.A mount of AAV-catalasse were delivered to each puppy.All AAV injected mice survived the procedure.Three months later, a 10-fold increase of catalase protein in skeletal muscle of injected mice were observed testing by western blot and Immunofluorescence staining.E group and CE group mice performed a single treadmill-running exercise bout.C group and CE group mice were delivered with AAV-Catalase virus.Gastrocnemius were obtained 2 h after exercise.PGC-1 gene expression in gastrocnemius were detected by realtime PCR.Result: Compared with WT group mice, PGC-1 a expression were significantly improved in E group mice after 2 hr treadmill running.Compared with C group mice,PGC-1 a expression were significantly improved in CE group mice after 2 hr treadmill running.There were no significant differences of PGC-1 a expression in skeletal muscle between E group mice and WT group mice.There were no significant differences of PGC-1 a expression in skeletal muscle between C group mice and CE group mice.Conclusion: Exercise induced PGC-1 gene expression in skeletal muscle.The PGC-1 gene expression induced by exercise was not influenced by physiological H2O2 induced by exercise.This indicated that H2O2 induced by exercise was not mandatory for exercise induced adaptive mitochondrial biogenesis in mice skeletal muscle.