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Bruno Paes de Arruda Matoso, Afonso Shiguemi Inoue Salgado, Doroty M. Dourado, Newton Santos de Faria Junior, Luis Vicente Franco de Oliveira, Renato Amaro Zangaro, Paulo de Tarso Camillo de Carvalho
Med Sci Tech 2010; 51(3-4): RA181-186
Background: Muscle injuries are common everyday occurrences, especially in athletes, and can lead to mechanical and metabolic changes in the injured structure. Low-level laser therapy (LLLT) has become an effective alternative for reducing muscle fatigue and its consequences. The objective of this study was to analyze the effect of a low-level AsGaAl laser (808 nm) on muscle fatigue induced in rats and to correlate creatine kinase (CK) levels with histological results.
Material/Methods: We used 15 Wistar rats that were distributed into 3 groups: a control group at rest, a muscle fatigue control group, and a muscle fatigue group treated with the laser. After undergoing a muscle fatigue-induction protocol by forced swimming, the treated group was irradiated with an AsGaAl laser (808 nm, 3.57 W/cm2, 100 mW and a 0.028 cm2 beam) applied transcutaneously to a single point on the gastrocnemius muscle with an energy density of 40 J/cm2. We analyzed CK levels and muscle histology, and the results from the average CK levels were statistically analyzed using the Kruskal-Wallis test and the Dunn post-hoc test, with a significance level of 0.05.
Results: The results for the crossover experiments between the control and laser groups were statistically significant (p<0.05). In the histological analysis, we did not observe any significant changes in the inflammatory cells after LLLT irradiation.
Conclusions: We conclude that the AsGaAl laser (808 nm) reduces the CK values in rats irradiated with LLLT (808 nm) after muscle fatigue.
Keywords: low-level laser (LLL), Muscle Fatigue, creatine kinase, Creatine Kinase - analysis