Electrical stimulation promotes motoneuron regeneration without increasing its speed or conditioning the neuron.
ABSTRACT Motoneurons reinnervate the distal stump at variable rates after peripheral nerve transection and suture. In the rat femoral nerve model, reinnervation is already substantial 3 weeks after repair, but is not completed for an additional 7 weeks. However, this "staggered regeneration" can be temporally compressed by application of 20 Hz electrical stimulation to the nerve for 1 hr. The present experiments explore two possible mechanisms for this stimulation effect: (1) synchronization of distal stump reinnervation and (2) enhancement of regeneration speed. The first possibility was investigated by labeling all motoneurons that have crossed the repair at intervals from 4 d to 4 weeks after rat femoral nerve transection and suture. Although many axons did not cross until 3-4 weeks after routine repair, stimulation significantly increased the number crossing at 4 and 7 d, with only a few crossing after 2 weeks. Regeneration speed was studied by radioisotope labeling of transported proteins and by anterograde labeling of regenerating axons, and was not altered by stimulation. Attempts to condition the neuron by stimulating the femoral nerve 1 week before injury were also without effect. Electrical stimulation thus promotes the onset of motor axon regeneration without increasing its speed. This finding suggests a combined approach to improving the outcome of nerve repair, beginning with stimulation to recruit all motoneurons across the repair, followed by other treatments to speed and prolong axonal elongation.
Article: Electrical stimulation to conductive scaffold promotes axonal regeneration and remyelination in a rat model of large nerve defect.[show abstract] [hide abstract]
ABSTRACT: Electrical stimulation (ES) has been shown to promote nerve regeneration when it was applied to the proximal nerve stump. However, the possible beneficial effect of establishing a local electrical environment between a large nerve defect on nerve regeneration has not been reported in previous studies. The present study attempted to establish a local electrical environment between a large nerve defect, and examined its effect on nerve regeneration and functional recovery. In the present study, a conductive scaffold was constructed and used to bridge a 15 mm sciatic nerve defect in rats, and intermittent ES (3 V, 20 Hz) was applied to the conductive scaffold to establish an electrical environment at the site of nerve defect. Nerve regeneration and functional recovery were examined after nerve injury repair and ES. We found that axonal regeneration and remyelination of the regenerated axons were significantly enhanced by ES which was applied to conductive scaffold. In addition, both motor and sensory functional recovery was significantly improved and muscle atrophy was partially reversed by ES localized at the conductive scaffold. Further investigations showed that the expression of S-100, BDNF (brain-derived neurotrophic factor), P0 and Par-3 was significantly up-regulated by ES at the conductive scaffold. Establishing an electrical environment with ES localized at the conductive scaffold is capable of accelerating nerve regeneration and promoting functional recovery in a 15 mm nerve defect in rats. The findings provide new directions for exploring regenerative approaches to achieve better functional recovery in the treatment of large nerve defect.PLoS ONE 01/2012; 7(6):e39526. · 4.09 Impact Factor
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ABSTRACT: To study electrodiagnostic findings and recovery patterns of patients with facial nerve paralysis. Seventy-six medical records of patients who had a facial paralysis and had their electrodiagnosis performed in a 2-year period were reviewed. Patients were invited for re-evaluation. The patients would be evaluated according to House-Brackmann Facial Nerve Grading Scale (HBFNGS), residual impairment, disability, emotional and social consequences. Complete data were obtained from 50 patients whose mean age was 47.0 +/- 17.9 years. Seventy-two percent were diagnosed as Bell's palsy. There was significant correlation between %CMAP amplitude and HBFNGS (grade I-VI) at r = 0.5; p < 0.01. All cases of Bell's palsy with CMAP amplitude > or = 70% of normal side regained full recovery. Patients with CMAP amplitude > or = 30% had good recovery. Bell's palsy with CMAP amplitude < 10% and with other causes had poor outcome. Nine patients had synkinesis. Most of them were of traumatic cause and had severe nerve degeneration. No evidence showed that electrical stimulation was a factor inducing synkinesis. Percent CMAP amplitude could moderately predict the outcome of Bell's palsy better than other causes of facial palsy. The paralysis from traumatic cause with low %CMAP amplitude had more chance to develop synkinesis.Journal of the Medical Association of Thailand = Chotmaihet thangphaet 11/2007; 90(10):2198-203.
Journal of Bone and Joint Surgery - British Volume 11/2005; 87(10):1309-19. · 2.83 Impact Factor