ABSTRACT
The aim of this study was to determine the effects of gallium arsenide (GaAs) laser on IGF-I, MyoD, MAFbx, and TNF-α gene expression during the intermediate phase of muscle regeneration after cryoinjury 21 Wistar rats were divided into three groups (n = 7 per group): untreated with no injury (control group), cryoinjury without GaAs (injured group), and cryoinjury with GaAs (GaAs-injured group). The cryoinjury was induced in the central region of the tibialis anterior muscle (TA). The region injured was irradiated once a day during 14 days using GaAs laser (904 nm; spot size 0.035 cm2, output power 50 mW; energy density 69 J cm-2; exposure time 4 s per point; final energy 4.8 J). Twenty-four hours after the last application, the right and left TA muscles were collected for histological (collagen content) and molecular (gene expression of IGF-I, MyoD, MAFbx, and TNF-α) analyses, respectively. Data were analyzed using one-way ANOVA at P < 0.05. There were no significant (P > 0.05) differences in collagen density and IGF-I gene expression in all experimental groups. There were similar (P < 0.05) decreases in MAFbx and TNF-α gene expression in the injured and GaAs-injured groups, compared to control group. The MyoD gene expression increased (P = 0.008) in the GaAs-injured group, but not in the injured group (P = 0.338), compared to control group. GaAs laser therapy had a positive effect on MyoD gene expression, but not IGF-I, MAFbx, and TNF-α, during intermediary phases (14 days post-injury) of muscle repair.
Subject(s)
Athletic Injuries/radiotherapy , Lasers, Semiconductor/therapeutic use , Low-Level Light Therapy , Muscle, Skeletal/injuries , MyoD Protein/genetics , Animals , Cold Temperature , Collagen/genetics , Collagen/metabolism , Gene Expression/radiation effects , Insulin-Like Growth Factor I/genetics , Insulin-Like Growth Factor I/metabolism , Male , Muscle, Skeletal/metabolism , Muscle, Skeletal/radiation effects , MyoD Protein/metabolism , Rats , Rats, Wistar , Tumor Necrosis Factor-alpha/genetics , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Abstract Introduction: Russian current is an electric current of average frequency that is able to restore the properties of skeletal muscle at a low treatment cost. It is essential to know the effects of Russian current in bone tissue, since electromagnetic energy could be an efficient and low cost method to treat bone disorders. Objective: The aim of the study was to evaluate the effectiveness of Russian current in the consolidation of tibia fracture in adult rats. Methods: 24 adult male Albinus Wistar rats wereused. The animals were divided randomly into two groups: control group (CG), composed of 12 animals, and Intervention Group (IG) consisting of 12 animals, both groups were submitted to osteotomy (proximal medial surface of the tibia). The IG underwent an electrical stimulation protocol with Russian current, while the CG did not undergo any kind of intervention. Euthanasia was performed in three animals of each group on the following days: 5, 10, 20, and 30 days of treatment. Results: The results suggested higher primary ossification, intense osteogenic activity, and increased thickness of the periosteum, characterizing more advanced ossification and a greater presence of trabecular bone marrow in rats in the group subjected to the treatment. In this way, we can assign one more beneficial effect to interventions with Russian current, for the treatment of postfracture rehabilitation. Conclusion: In both groups the bone tissue repair process occurred, but in the electrically stimulated group the osteogenesis process was more advanced.
Resumo Introdução: A corrente russa é uma corrente elétrica de média frequência que é capaz de restabelecer as propriedades do músculo esquelético a baixo custo de tratamento. É imprescindível conhecer os efeitos da corrente russa no tecido ósseo, visto que a energia eletromagnética pode ser uma forma eficiente e de menor custo para tratar alterações ósseas. Objetivo: Avaliar a eficácia da corrente russa na consolidação de fratura experimental de tíbia em ratos adultos. Métodos: Foram utilizados 24 ratos machos adultos Albinus Wistar. Os animais foram distribuídos de forma randomizada em dois grupos: Grupo Controle (GC), composto por 12 animais e Grupo Intervenção (GI) compostos por 12 animais, ambos os sofreram osteotomia (face medial proximal da tíbia). O GI foi submetido a um protocolo de eletroestimulação com corrente russa, enquanto o GC não sofreu nenhum tipo de intervenção. Foi realizada a eutanásia de três animais de cada grupo nos seguintes períodos: 5°, 10°, 20° e 30° dia de tratamento. Resultados: Os resultados sugeriram maior ossificação primária, intensa atividade osteogênica e aumento da espessura de periósteo, caracterizando assim uma ossificação mais avançada com maior presença de trabéculas na medula óssea no grupo de ratos submetidos ao tratamento. Desta forma, pode-se atribuir mais um efeito benéfico nas intervenções com corrente russa, para o tratamento de reabilitação pós-fratura. Conclusão: Em ambos os grupos analisados ocorreu processo de reparação tecidual ósseo, porém no grupo eletroestimulado o processo de osteogênese foi mais avançado.