Comparative Effects of Low-Intensity Pulsed Ultrasound and Low-Level Laser Therapy on Injured Skeletal Muscle

Abstract

Objective: the main purpose of this study was to compare the effects of low-intensity pulsed ultrasound (US) and low-level laser therapy (LLLT) on injured skeletal muscle after cryolesion by means of histopathological analysis and immunohistochemistry for cyclo-oxygenase-2 (COX-2). Background and Methods: Thirty-five male Wistar rats were randomly distributed into four groups: intact control group with uninjured and untreated animals; injured control group with muscle injury and no treatment; LLLT-treated group with muscle injury treated with 830-nm laser; and US-treated group with muscle injury treated with US. Treatments started 24 h postsurgery and were performed during six sessions. Results: LLLT-treated animals presented minor degenerative changes of muscle tissue. Exposure to US reduced tissue injuries induced by cryolesion, but less effectively than LLLT. A large number of COX-2 positive cells were found in untreated injured rats, whereas COX-2 immunoexpression was lower in both LLLT-and US-treated groups. Conclusion: This study revealed that both LLLT and US therapies have positive effects on muscle metabolism after an injury in rats, but LLLT seems to produce a better response.Universidade Federal de São Paulo, UNIFESP, Dept Biosci, Santos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Physiotherapy, Santos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Biosci, Santos, SP, BrazilUniversidade Federal de São Paulo, UNIFESP, Dept Physiotherapy, Santos, SP, BrazilWeb of Scienc