Modulation of exercise-induced muscular damage and hyperalgesia by different 630 nm doses of light-emitting diode therapy (LEDT) in rats.
We compared the acute effects of different doses of 630 nm light-emitting diode therapy (LEDT) on skeletal muscle inflammation and hyperalgesia in rats submitted to exercise-induced muscle damage (EIMD). Wistar rats were divided into five experimental groups (n = 5-8/group): sedentary control (CON); exercise + passive recovery (PR); and exercise + LEDT (1.2 J/cm2, 1.8 J; 4.2 J/cm2, 6.3 J; 10.0 J/cm2, 15 J). After 100 min of swimming, the rats in the LEDT groups were exposed to phototherapy on the triceps surae muscle. For mechanical hyperalgesia evaluation, paw withdrawal threshold was assessed before and 24 h after swimming. Immediately after hyperalgesia tests, blood samples were collected to analyze creatine kinase (CK) activity and the soleus muscle was removed for histological and tumor necrosis factor (TNF)-α immunohistological analyses. In all LEDT groups, plasma CK activity was reduced to levels similar to those measured in the CON group. Paw withdrawal threshold decreased in the PR group (- 11.9 ± 1.9 g) when compared to the CON group (2.2 ± 1.5 g; p < 0.01) and it was attenuated in the group LEDT 4.2 J/cm2 (- 3.3 ± 2.4 g, p < 0.05). Less leukocyte infiltration and edema and fewer necrotic areas were found in histological sections of soleus muscle in LEDT (4.2 J/cm2) and LEDT (10.0 J/cm2) groups compared to the PR group. Also, LEDT (4.2 J/cm2) and LEDT (10.0 J/cm2) groups showed less immunostaining for TNF-α in macrophages or areas with necrosis of muscle fibers compared to the PR group. LEDT (4.2 J/cm2, 6.3 J)-reduced muscle inflammation and nociception in animals submitted to EIMD.
['Vasconcelos|Alan B|AB|', 'Nampo|Fernando K|FK|', 'Molina|Júlio C|JC|', 'Silva|Miriam B|MB|', 'Oliveira|Alan S|AS|', 'de Angelis|Tarlyson R|TR|', 'Hasuda|Amanda L|AL|', 'Camargo|Enilton A|EA|http://orcid.org/0000-0003-2745-0768', 'Ramos|Solange P|SP|']
D000818:Animals D003402:Creatine Kinase D004307:Dose-Response Relationship, Radiation D004487:Edema D006930:Hyperalgesia D007958:Leukocyte Count D007962:Leukocytes D008027:Light D008297:Male D018482:Muscle, Skeletal D009336:Necrosis D010789:Phototherapy D010805:Physical Conditioning, Animal D017208:Rats, Wistar D013550:Swimming D014409:Tumor Necrosis Factor-alpha
Light-emitting diode Skeletal muscle Inflammation Phototherapy Pain Physical exercise