Motor Cortex Stimulation Regenerative Effects in Peripheral Nerve Injury: An Experimental Rat Model.

Abstract

Immediate microsurgical nerve suture remains the gold standard after peripheral nerve injuries. However, functional recovery is delayed, and it is satisfactory in only 2/3 of cases. Peripheral electrical nerve stimulation proximal to the lesion enhances nerve regeneration and muscle reinnervation. This study aims to evaluate the effects of the motor cortex electrical stimulation on peripheral nerve regeneration after injury. Eighty rats underwent right sciatic nerve section, followed by immediate microsurgical epineural sutures. Rats were divided into 4 groups: Group 1 (control, n= 20): no electrical stimulation; group 2 (n= 20): immediate stimulation of the sciatic nerve just proximal to the lesion; Group 3 (n= 20): motor cortex stimulation (MCS) for 15 minutes after nerve section and suture (MCSa); group 4 (n= 20): MCS performed over the course of two weeks after nerve suture (MCSc). Assessment included electrophysiology and motor functional score at day 0 (baseline value before nerve section), and at weeks 4, 8, and 12. Rats were euthanized for histological study at week12. Our results showed that MCS enhances functional recovery, nerve regeneration, and muscle reinnervation starting week 4 compared with the control group (P < 0.05). The MCS induces higher reinnervation rates even compared with peripheral stimulation, with better results in the MCSa group (P < 0.05), especially in terms of functional recovery. MCS seems to have a beneficial effect after peripheral nerve injury and repair in terms of nerve regeneration and muscle reinnervation, especially when acute mode is used.