Effects of glycerol injection into rat sciatic nerve.

In recent years, injection of pure glycerol into the trigeminal cistern has been used for the treatment of trigeminal neuralgia. The mechanism of action of this therapy remains unclear. Using both light and electron microscopy, we investigated the effects of microinjections of sterile, pure glycerol into the endoneurium of the sciatic nerve of the rat. We observed total destruction of both myelinated and unmyelinated fibers. In nearly all animals, signs of automutilation were observed in the paralyzed limb. Histological evidence of nerve degeneration appeared soon after injection, with intense proliferation of perineurial cells that eventually divided the endoneurium into numerous microcompartments.