Influence of low intensity laser therapy (AsGa) on the cicatrization process of mechanic tendon injury in wistar rats

The aim of this study was to compare the effect of the low level Laser therapy (AsGa) in the experimental tendon injury. Low level Laser therapy has been used in several studies to observe the regenerative quality and tecidual cicatrization. Forty Wistar rats (male) were divided into 4 groups: control group (C-group); injury group (L-group); treated group with Laser therapy 3 J/cm(2) (3J-group); and treated group with Laser therapy 6 J/cm(2) (6J-group). Groups L, 3J, and 6J were submitted to a mechanic Achilles tendon injury with a Kocher Forceps for 10 s. The animals were sacrificed after ten days of treatment. Histopathological evaluation using hematoxylin-eosin and Picro-Sirius staining showed a decreased (p < 0.05) of collagen in L-group (353.12 +/- 9.85 mu m(2)/field) compared to C-group (215.13 +/- 22.63 mu m(2)/field). Animals treated with Laser showed a significant increase in collagen fibers despite the applied dosage (3J-group: 375.89 +/- 26.99 mu m(2)/field; 6J group: 400.34 +/- 62.92 mu m(2)/field; p < 0.05). These data suggest that low-level Laser therapy was efficient for the treatment of mechanics Achilles tendon injury in Wistar rats.