Abstract
Functional electrical stimulation (FES) has been proposed as a potential treatment for restoring the motor functions of denervated motor systems. Furthermore, FES on denervarted muscle has the potential to prevent muscle atrophy and promote reinnervation.
In this study, to assess these effects of FES, we evaluated what kind of changes occurred in neuromuscular junctions (NMJ) by FES to muscle after denervation. Tibialis anterior muscles of rats were used for this study. A sciatic nerve anastomosis was performed after having cut off the nerve. We applied electric stimulation (2Hz, 0.5ms, 4.0mA) three days a week to the rats. Electric stimulation was performed using surface electrode percutaneously for an hour. The rats were euthanized 2, 4 or 8 weeks after treatment. To evaluate the number of axon nerve terminals and acetylcholine receptors (AchRs), synaptic vesicles of the nerve endings were labeled using antisynaptophysin antibody and AchRs were labeled by α-Bungarotoxin. We analyzed the effects of FES by counting the number of AchRs and axon nerve terminals. The number of AchRs decreased slightly after denervation for the group that did not receive electrical stimulation; whereas, the group that did have electrical stimulation to the denervated muscles increased the number of AchRs. After denervation the number of nerve terminals decreased at once and gradually increased according to completion of reinnervation. Electrical stimulation promoted regenerating nerve terminals during the reinnervation process. From the results of this study, we confirmed that electrical stimulation promoted regenerating NMJ during reinnervation process.
