Efeitos da estimulação elétrica neuromuscular sobre o membro posterior imobilizado de ratos durante 15 dias: análises metabólicas e morfométricas

Abstract

RESUMOObjetivo: Avaliar o efeito da estimulação elétrica (EE) sobre o perfil metabólico e morfométrico dos músculos do membro posterior de ratos submetidos à imobilização durante 15 dias. Método: Ratos Wistar foram divididos em 3 grupos (n=5): controle, imobilizado por 15 dias e imobilizado associado à EE por 15 dias. Foram avaliados: reserva de glicogênio (RG) dos músculos sóleo (S), extensor longo dos dedos (ELD), gastrocnêmio branco (GB), gastrocnêmio vermelho (GV) e tibial anterior (TA), além do peso do sóleo, área das fibras e tecido conjuntivo do S. A análise estatística foi feita pelos testes ANOVA e Kruskal-Wallis (p<0,05). Resultados: A imobilização promoveu alterações significativas (p<0,05) como: redução nas RG (S: 44,73%, GB: 47,82%, GV: 46,34%, ELD: 41,66%, TA: 48,38%), no peso (7,2%) e na área das fibras (35%) do S, além do aumento da densidade do tecido conjuntivo (160%). A EE promoveu aumento significativo (p<0,05) nas RG de todos os músculos imobilizados (S: 90,47%, GB: 62,5%, GV: 95,45%, ELD: 76,19%, TA: 56,25%), no peso (20,94%) e na área das fibras (19,65%) do S e também promoveu redução significativa (15,38%, p<0,05) na densidade do tecido conjuntivo. Conclusões: A EE minimizou a redução das RG, preveniu a redução da área das fibras e a proliferação do tecido conjuntivo nos músculos submetidos à imobilização.Palavras-chave: estimulação elétrica, imobilização, morfometria, metabolismo, fisioterapia. ABSTRACT Effects of Neuromuscular Electrical Stimulation on Rat Hind Limbs Immobilized for 15 Days: Metabolic and Morphometric AnalysesObjective: To evaluate the effect of electrical stimulation on the metabolic and morphometric profile of rat hind limb muscles subjected to immobilization for 15 days. Method: Wistar rats were divided into three groups (n=5): control; immobilized for 15 days; and immobilized for 15 days with electrical stimulation. The glycogen reserves of the soleus, extensor digitorum longus (EDL), white gastrocnemius (WG), red gastrocnemius (RG) and tibialis anterior (TA) muscles were evaluated, along with the weight, fibrous area and conjunctive tissue of the soleus.

Effect of electrical stimulation of the cranial tibial muscle after end-to-side neurorrhaphy of the peroneal nerve in rats

“…35 During the electrophysiological test, the rats in denervated group that showed no response to electrical stimuli, for just not having the connection between nerve and muscle, were therefore removed from the statistical analysis. Tagami et al 14 Our study is unique in that no others researches has utilized the same model to make purposeful comparisons, since most studies using electrical stimulation in denervated muscle spans seven to 52 days of observation and therefore could not possibly asess the functional evolution of animals using histological means in most cases 25,27,28,36,37 . As our duration of stimulation is relatively high and, the rats would have to undergo several sessions of ES, it was be too risky to anesthetize the rats everytime they were receiving treatment.…”

“…The current intensity was also determined by previous studies where we found the ideal point for muscular contraction. In our literature review, we found studies using intensity ranges from 1 mA to 5 mA , however, these studies used anesthetized rats or implanted electrodes 24,25,27,28,36 .…”

“…In addition to the metabolic effects, ES also helps in minimizing the effects of immobilization, minimizing the reduction of cross-sectional area, interstitial fibrosis and deficiency of blood supply 22 . ES promotes increased effectiveness of contractile muscle fibers, enabling thus the dynamics of uptake via GLUT-4, glucose metabolism and activity of cellular metabolic pathways [23][24][25][26][27][28] .…”

Twice a day neuromuscular electrical stimulation postimmobilization alters the mechanical properties and the histomorphometry of the skeletal muscle

“…These results suggest that the transitions were in the opposite directions from the TIIaF↔TIIbF↔TIIdbF↔TIIdF↔TIIadF↔TIIaF↔ TIIcF↔TIF. However, when the NMES was applied for a longer period than used in this study, with a low frequency (10 Hz), the fibers to be first recruited were the TIIdFs, which underwent transition in one-way, being in the TIIdF↔TIIadF↔TIIaF↔TIF direction [28]. Thus, it can be seen that, regardless of the applied time of NMES, the initial recruitment involved the TIIF fibers [30], even though a fiber transition occurs later.…”

“…The quantitative data for the 1ESIG indicate a return of TIF and TIIdF to the control conditions, what would justify responses proportional load and elongation. Studies using NMES once a day during [11,28] and after periods of immobilization [10], or applying it to healthy animals have detected an increase in the cross-sectional area (CSA) of the muscle fibers with a predominance of TIF and TIIF in the gastrocnemius muscle [10,11,28]. Data regarding the proportions of muscle fibers seem to indicate that NMES applied once a day increased the percentage of TIIcF in both portions of the gastrocnemius muscle, on the other hand reduced the TIIaF quantity.…”