Comparação entre o laser de baixa potência, ultrassom terapêutico e associação, na dor articular em ratos Wistar

Abstract

IntroductionBoth therapeutic ultrasound as a low level laser therapy are used to control musculoskeletal pain, despite controversy about its effects, yet the literature is poor and also presents conflicting results on possible cumulative effects of techniques association. The aim was to compare the antinociceptive effects of low level laser therapy, therapeutic ultrasound and the association. Methods24 Wistar rats were divided into: GPL – induction of hyperesthesia in the right knee, and untreated; GUS – treated with therapeutic ultrasound (1MHz, 0.4W/cm2) GL – low intensity laser (830nm, 8J/cm2); GL+US – treated with both techniques. To produce the hyperesthesia 100μl of 5% formalin solution were injected into the tibiofemoral joint space, which was assessed by von Frey filament digital before (EV1), 15 (EV2), 30 (EV3) and 60 (EV4) minutes after induction. ResultsIn comparison within groups, for the withdrawal threshold when the filament was applied to the knee, the back to baseline was observed only for GUS. Comparisons between groups were not different in EV3, and GL was higher than GPL. In EV4 the three groups effectively treated were higher than placebo. On withdrawal threshold on the plantar surface, GL showed return to baseline values already in EV3, and GUS and GL+US returned in EV4. Comparing the groups in EV3 there was a significantly lower threshold to compare GPL with GL and GUS (p <0.05), and there was only EV4 differences when comparing GPL with GUS. ConclusionBoth modalities showed antinociceptive effects.