RESUMO
OBJECTIVE: Electrical stimulation is a procedure used to treat denervated muscles. The number of electrical stimulation sessions varies across muscle rehabilitation protocols, from daily to certain days throughout the week. The purpose of this study was to evaluate how muscle and nerve respond to different intervals of electrical stimulation applied to denervated muscle. DESIGN: Denervation of rat gastrocnemius muscle was imposed via nerve crush, and electrical stimulation was applied to the muscle either daily (Monday through Friday) or on alternate days (Monday, Wednesday, and Friday). Four experimental groups were studied: denervated, denervated plus daily electrical stimulation, denervated plus alternate-day electrical stimulation, and control. RESULTS: On the 12th day after nerve crush, levels of MyoD, myostatin, and atrogin-1 gene expression, as well as muscle fiber and nerve morphometry, were evaluated. Expression levels of all three genes were higher in the denervated group when compared with control. Also, expression levels of MyoD and myostatin were higher in denervated plus alternate-day electrical stimulation and denervated plus daily electrical stimulation groups when compared with denervated. The denervated plus daily electrical stimulation group had lower atrogin-1 expression, lower density of intramuscular connective tissue, and better morphometric nerve characteristics when compared with the denervated and denervated plus alternate-day electrical stimulation. CONCLUSIONS: These results indicate that the responses of both muscle and nerve to electrical stimulation after muscle denervation depend on the intervals of electrical stimulation application.
Assuntos
Estimulação Elétrica , Músculo Esquelético/inervação , Animais , Estimulação Elétrica/métodos , Terapia por Estimulação Elétrica/métodos , Masculino , Denervação Muscular , Proteínas Musculares/metabolismo , Proteína MyoD/metabolismo , Miostatina/metabolismo , Ratos , Proteínas Ligases SKP Culina F-Box/metabolismo , Fatores de TempoRESUMO
O Tecido Conjuntivo é responsável pela integridade morfológica e funcional do músculo, sendo que este sofre adaptações após estímulos como imobilização, lesão e envelhecimento, entre outros. A imobilização é um recurso frequentemente utilziado na prática clínica, porém, acarreta prejuízos no músculo. Diversos recursos, como a eletroestimulação, a mobilização e o alongamento, são utilizados para minimizar os efeitos desencadeados pela imobilização. Sendo assim, o objetivo deste artigo foi realizar uma revisão dos efeitos da imobilização sobre o tecido conjuntivo intramuscular assim como dos efeitos de alguns recursos utilziados para reorganização adequada deste tecido
The connective tissue is responsible for the morphological and functional integrity of the muscle, and it is able to adapt after some stimuli such as immobilization, lesion and aging among others. The immobilization is an approach commonly used to treat injuries in the muscle skeletal system; however, it causes some undesirable muscle alteration. There are several procedures that are used to minimize the effects caused by immobilization, such as electrical stimulation, mobilization and stretch.l.
