The effects of different electrical stimulation protocols on nerve regeneration through silicone conduits

Background: The effects of electrical stimulation on the regeneration of transected nerves through silicone rubber conduits may depend on the stimulation protocol. Methods: Rat sciatic nerve was transected and reconnected using a silicone rubber conduit with a 7-mm gap. The subjects were divided into nine groups. Each group received one protocol of electrical stimulation 30 minutes each day for 3 weeks. The effects of electrical stimulation were evaluated through morphologic methods. Results: Direct current stimulation increased nerve fiber bundle area without significantly affecting the number of myelinated fibers, resulting in decreased nerve fiber density. All the pulse current stimulation protocols as a group decreased the nerve fiber bundle area without affecting the number of myelinated fibers, resulting in increased nerve fiber density. Within the pulse current stimulation protocols, stimulation frequency affected nerve fiber density, whereas current strength did not. Conclusions: Stimulation protocols had significant influences on the benefit of electrical stimulation in nerve regeneration.