Effects of volatile anesthetics on peripheral nerve regeneration in a sciatic cut repair murine model

We previously showed that 2% isoflurane conditioning promoted axonal and myelin regeneration leading to improved functional outcomes after peripheral nerve injury (PNI) in a sciatic nerve cut repair model. Whether the 1 MAC (minimum alveolar concentration) dose of isoflurane (1.2%) and other commonly used volatile anesthetics such as sevoflurane (2%), and desflurane (6%), support peripheral nerve regeneration is not known. The aim of the current study is to examine these possibilities in a rodent sciatic nerve injury model.

Twelve-week-old male Lewis rats underwent sciatic nerve cut and repair and were divided into following groups. (1) control (no treatment), (2) isoflurane (1.2%), (3) sevoflurane (2%), and (4) desflurane (6%). Volatile anesthetic conditioning was achieved by administering isoflurane, sevoflurane, and desflurane for 1 h, beginning 1-h post sciatic nerve cut and repair, and the anesthetic exposure was repeated for the next two consecutive days for 1 h. Functional outcomes such as compound muscle action potential (CMAP), evoked muscle force (tetanic and specific tetanic force), wet muscle mass, and axonal counts were measured at 12 weeks post-surgery.

A significant increase in the axonal numbers and myelin width was observed in the desflurane group. This was associated with the improvement in the specific tetanic force measured at 12 weeks post-surgery.

Desflurane promoted axonal regeneration and myelination at 12 weeks post-peripheral nerve injury and repair in a murine model. Future experiments focusing on identifying the optimal dose to improve functional outcomes, and the molecular mechanisms underlying desflurane's potential protective effect are warranted.