Effects of photobiomodulation therapy and topical non-steroidal anti-inflammatory drug on skeletal muscle injury induced by contusion in rats—part 1: morphological and functional aspects

Abstract

Musculoskeletal injuries are very frequent and are responsible for causing pain and impairment of muscle function, as well as significant functional limitations. In the acute phase, the most prescribed treatment is with non-steroidal anti-inflammatory drugs (NSAIDs), despite their questionable effectiveness. However, the use of photobiomodulation therapy (PBMT) in musculoskeletal disorders has been increasing in the last few years, and this therapy appears to be an interesting alternative to the traditional drugs. The objective of the present study was to evaluate and compare the effects of PBMT, with different application doses, and topical NSAIDs, under morphological and functional parameters, during an acute inflammatory process triggered by a controlled model of musculoskeletal injury induced via contusion in rats. Muscle injury was induced by means of a single trauma to the animals' anterior tibialis muscle. After 1 h, the rats were treated with PBMT (830 nm; continuous mode, with a power output of 100 mW; 3.57 W/cm; 1 J-35.7 J/cm, 3 J-107.1 J/cm, and 9 J-321.4 J/cm; 10, 30, and 90 s) or diclofenac sodium for topical use (1 g). Morphological analysis (histology) and functional analysis (muscle work) were performed, 6, 12, and 24 h after induction of the injury. PBMT, with all doses tested, improved morphological changes caused by trauma; however, the 9 J (321.4 J/cm) dose was the most effective in organizing muscle fibers and cell nuclei. On the other hand, the use of diclofenac sodium produced only a slight improvement in morphological changes. Moreover, we observed a statistically significant increase of muscle work in the PBMT 3 J (107.1 J/cm) group in relation to the injury group and the diclofenac group (p < 0.05). The results of the present study indicate that PBMT, with a dose of 3 J (107.1 J/cm), is more effective than the other doses of PBMT tested and NSAIDs for topical use as a means to improve morphological and functional alterations due to muscle injury from contusion.

PBMT and topical diclofenac as single and combined treatment on skeletal muscle injury in diabetic rats: effects on biochemical and functional aspects

“…To our knowledge, this is the first study to investigate the effects of PBMT used in combination with NSAIDs in diabetic rats, compared with NSAID treatment alone, which is a first-line drug for treatment of muscle injury [14].…”

“…In addition, the use of NSAIDs in a topical manner deserves to be highlighted, since it presents lower adverse effects than oral NSAIDs (for example, [10,14]). Finally, the functional analysis of the rats, through the walking track analysis, also deserves attention, since the main objective at the end of a treatment for muscular injury is the return of normal function of the treated segment.…”

“…It is known that hyperglycemia can generate an imbalance in the production of growth factors, an increase in the inflammatory process, and impair cellular functions, thus causing a delay in the process of tissue repair [2,3]. According to Tomazoni et al [14,15], NSAID therapy is the most commonl y u s e d t r e a t m e n t f o r m u s c u l a r l e s i o n s a n d photobiomodulation therapy (PBMT) is effective in reducing inflammatory markers, as well as improving repair of injured musculoskeletal tissue, at the energy density of 107.1 J/cm 2 and total energy of 3 J.…”

“…It is important to emphasize that functional tests are very important in the analysis of muscle tissue, to better understand its evolution [14]. In our study, we used the functional analysis called walking track analysis to evaluate the gait of the rats.…”

“…PBMT seems to work very well in traumatic muscle injuries. Recently, in two studies, Tomazoni et al [14,15] demonstrated the efficacy of PBMT in the repair of trauma injuries, regarding morphological, biochemical, and functional aspects, using an 830-nm laser and a dose of 3 J. Furthermore, works can be found in the literature with positive results of treatment with photobiomodulation therapy in wound healing and cryolesions [16,17].…”