Investigating the Effects of Brief Electrical Stimulation Duration on Sciatic Nerve Regeneration and Functional Recovery in a Rat Transection Model

Abstract

Background. Periodic and brief electrical stimulations (ES) are used as therapeutic protocols to improve nerve regeneration and functional recovery in various nervous system disorders. Periodic ES is applied transcutaneously for several sessions post-surgery, but brief ES is applied directly to the nerve during the surgery. Brief ES has no negative effects on functional recovery but applying periodic ES may delay the recovery. Objective. In most research studies, brief ES has been applied for 1-hour, although in some studies shorter durations were used. In this research, to reduce the risk of infection and cost, brief ESs with different durations (1-hour and shorter durations) were studied in a comparative study. Methods. The right sciatic nerve of 24 adult male Wistar rats was transected and sutured to a silicone tube. Experimental groups stimulated by 10, 30, and 60 minutes ES (20Hz, 3V, 100µs). The hot plate test was done biweekly. At the end of the experimental period (12 weeks), the histomorphometric assessments were performed on the intra silicon tube segment of the regenerated nerve and its tibial branch.Results. Hot plate test results showed an increase in the regeneration speed in experimental groups; furthermore, the 60-min ES group had better outcomes in histomorphometric assessment than other groups that may be due to ES effect on the neuronal cell bodies.Conclusion. As the results indicate, the 60-min ES had a better outcome compared to other groups. Other specifics of a brief ES such as frequency, pulse width, and waveform (monophasic or biphasic) may be studied in future research.