The low-level laser on acute myositis in rats

PURPOSE: To analyze the effects of the low-level laser therapy in the acute myositis induced in rats. METHODS: Fifteen male Wistar rats (Rattus norvegicus) were randomly distributed into three categories: control group (C), induced Myositis without treament (MI) and treated induced myositis (MT), for the experimental period of seven days. The induction of the acute myositis was done with 1% acetic acid by intramuscular route. The rats belonging to the experimental group had daily treatment through the GaAs (gallium arsenide) laser, with 904,0 nm length, and 45 mW peak power, with 3J/cm(2), applied for 5 minutes on the animals' right posterior limb. RESULTS: In the MT group there was a statistic significant decrease in the number of inflammatory cells, related to the MI group (p<0.05), increase in the fibroblastic proliferation, when compared to groups C and MI related to MT group (p<0.01) and statistic significant edema regression (p=0.0400) in the MT group. CONCLUSION: The low-level laser therapy was efficient in the reduction of the inflammatory process, increase of the fibroblastic proliferation and the reduction of the edema.