Voluntary exercise alleviates ischemic brain injury in mice by modulating mitochondrial dysfunction.

OBJECTIVES: The relationship between exercise and mitochondrial function is unclear. This study investigated the relationship between voluntary exercise and mitochondrial dynamics in ischemic stroke model mice. MATERIALS AND METHODS: This experiment used 54 male C57BL/6 J mice to assess the therapeutic effect of voluntary exercise on ischemic stroke in a middle cerebral artery occlusion (MCAO) model. Body weight and the number of wheel turns were recorded to monitor the physiological condition of the mice. The degree of brain injury was evaluated via hematoxylin and eosin (H&E) staining and measurement of the cerebral infarction volume. Western blotting and immunofluorescence were used to measure dynein-1-like protein 1 (DRP1), mitochondrial fission protein 1 (FIS1), and optic atrophy type 1 (OPA1) levels to assess mitochondrial dynamics and analyze the degree of mitochondrial apoptosis by measuring cytochrome c (CYT-C), cleaved caspase-3, and caspase-3 expression. RESULTS: Voluntary exercise positively affected the behavioral score and infarct volume. H&E staining revealed that voluntary exercise reversed MCAO-induced cortical damage. Furthermore, voluntary exercise improved mitochondrial dynamics by inhibiting DRP1 and FIS1 expression and inducing OPA1 expression. Additionally, the mitochondrial apoptosis pathway was inhibited by down-regulating the expression of CYT-C, cleaved caspase-3, and caspase-3. CONCLUSION: Voluntary exercise exerts a significant neuroprotective effect against MCAO-induced brain injury by regulating mitochondrial dynamics and the mitochondrial apoptotic pathway.