Efeitos da radiação laser de baixa potência com comprimentos de onda de 660nm e 904nm em um modelo experimental de osteoartrose

Abstract

The objective of this study was to analyze the influence of low power laser radiation with 660nm and 904nm wave length in a experimental model of osteoarthritis. The sample was composed by 54 Wistar male adult rats divided into three groups called G1, G2 and G3. In order to induce the lesion three infiltrations with 10 μl of papain 4% solution and adding 10 μl of cysteine solution were carried out in the right knee. 2 weeks after the last infiltration, group G1 was treated with 660nm, 6J/ cm² laser, 6 spots around the knee articulation, 16 seconds each spot. Group G2 was treated with 904nm laser, 288 seconds, 6 J/cm² in 4 spots and group G3 was adopted as control group. The data were submitted to statistic analysis using the Kruskal Wallis test and the level of significance established at p<0.05. As for the kind of revestment of synovial membrane found, there was statistically significant difference between 7 and 14 days (p<0.05) in group G2, and in the period of 14 days between groups G1 and G2 (p<0.05). As far as the formation of new vessels is concerned there was statistically significant difference when G1 was compared to G3 in the period of 7 and 21 days and G2 to G3 in 21 days. The formation of fibrotic tissue was also higher in G3 (p<0.05). We concluded that laser therapy stimulates angiogenesis and reduces the fibrosis formation in experimental model of osteoarthritis, mainly with the use of laser with 904nm wave length.