title: Effects of low-level laser irradiation on rat skeletal muscle injury after eccentric exercise.
abstract: OBJECTIVE
  The effect of photobiomodulation on delayed onset muscle soreness remains unknown. This study represents the first investigation of this treatment using an animal model.
  
  
  METHODS
  Seventy-two Sprague-Dawley rats were randomly divided into five groups: sedentary control group, exercise control group and three exercise-plus-laser groups. Downhill running was used to induce muscle injury in the gastrocnemius muscle. He-Ne laser irradiations were administered to the injured muscles immediately and at 18 and 42 h after exercise in the three exercise-plus-laser groups at 12, 28, and 43 J/cm2, respectively. Histological examination and serum creatine kinase (CK), muscle superoxide dismutase (SOD) and malondialdehyde (MDA) analyses were done at 24 and 48 h after exercise.
  
  
  RESULTS
  The exercise control group exhibited a marked inflammation in the gastrocnemius muscle and significant elevations in serum CK activity and muscle MDA level after downhill running. He-Ne laser irradiation at 43 J/cm2 inhibited muscle inflammation, significantly enhanced muscle SOD activity and significantly reduced serum CK activity and muscle MDA level at both 24 and 48 h after exercise, whereas the irradiation at 12 or 28 J/cm2 slightly inhibited muscle inflammation and significantly reduced serum CK activity at 48 h after exercise only (P<0.05).
  
  
  CONCLUSIONS
  Low-level He-Ne laser therapy could exert therapeutic effects on eccentric exercise-induced rat muscle injury through enhancing muscle anti-oxidative capacity and reducing the inflammatory reaction. The photobiomodulation was dose-dependent, and the 43 J/cm2 dose was the most efficient among the doses used.
authors.affiliation: Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Liu
authors.forename: Yong-Jian
authors.initials: YJ
authors.lastname: Zhou
authors.forename: Timon Cheng-Yi
authors.initials: TC
authors.lastname: Liu
authors.forename: Jian-Qin
authors.initials: JQ
authors.lastname: Yuan
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003402:Creatine Kinase / Q000097:blood; D004307:Dose-Response Relationship, Radiation; D005260:Female; D007249:Inflammation / Q000532:radiotherapy*; D028022:Low-Level Light Therapy / Q000379:methods*; D008315:Malondialdehyde / Q000378:metabolism; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism; D010805:Physical Conditioning, Animal; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D008315:Malondialdehyde; D013482:Superoxide Dismutase; D003402:Creatine Kinase