title: Low-intensity laser irradiation improves the mitochondrial dysfunction of C2C12 induced by electrical stimulation.
abstract: OBJECTIVE
  We investigated the effects of electrical stimulation and low-intensity laser (LIL) energy on the mitochondrial function of cultured C2C12 myotubes in order to find a dosage that could be used to improve the function of mitochondria, and then rehabilitate exercise-induced damage and fatigue.
  
  
  BACKGROUND
  Many other studies in the past demonstrated that LIL had a cytoprotective effect, and a recent study also found that LIL could reduce muscular fatigue during tetanic contractions in rats.
  
  
  METHODS
  Cultured C2C12 myotubes were subjected to electrical stimulation or/and LIL irradiation at various intensities. Reactive oxygen species (ROS) were detected with a fluorescent probe (DCFH-DA) and mitochondrial function was assessed with an MTT assay.
  
  
  RESULTS
  The results showed that electrical stimulation at 20 ms, 5 Hz, and 45 V for 75 min can induce mitochondrial dysfunction in cultured C2C12 myotubes. Electrical stimulation-induced mitochondrial dysfunction was improved, but degeneration occurred with LIL at doses of 0.33-8.22 and 11.22-14.16 J/cm2, respectively, and these changes were markedly increased with LIL at 0.33 and 1.34 J/cm2, respectively.
  
  
  CONCLUSIONS
  We conclude that treatment of myotubes with the proper dosage of LIL irradiation significantly diminished production of ROS and restored mitochondrial function, and this may provide a foundation for the use of photobiomodulation to treat exercise-induced mitochondrial dysfunction or skeletal muscular fatigue.
authors.affiliation: Laboratory of Laser Sports Medicine, College of Sports Sciences, South China Normal University, Guangzhou, China. xuxy@scnu.edu.cn
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Xu
authors.forename: Xiufeng
authors.initials: X
authors.lastname: Zhao
authors.forename: Timon Cheng-Yi
authors.initials: TC
authors.lastname: Liu
authors.forename: Hongying
authors.initials: H
authors.lastname: Pan
mesh_terms: D000818:Animals; D002460:Cell Line; D004558:Electric Stimulation; D007834:Lasers; D051379:Mice; D008931:Mitochondria, Muscle / Q000502:physiology / Q000528:radiation effects*; D009119:Muscle Contraction / Q000528:radiation effects; D018763:Muscle Fatigue; D018485:Muscle Fibers, Skeletal / Q000528:radiation effects*