Enhancement of mouse sciatic nerve regeneration by the long chain fatty alcohol, N-hexacosanol

The purpose of the present study was to determine the effects of n-hexacosanol (hexa) on nerve regeneration. Hexa, a long chain fatty alcohol has been shown to possess neurotrophic properties on cultured neurons and to attenuate the degeneration of cholinergic neurons after injury. The effects of daily intraperitoneal injections of hexa (1 mg/kg) on regeneration of nerve fibers were studied in mice following a sciatic nerve crush. Measurement of axonal regeneration using the pinch test 7 days postlesion showed a 40% increase of the regeneration rate of sensory fibers in hexa-treated mice compared to controls (1.67 +/- 0.15 mm/day and 1.09 +/- 0.03 mm/day, respectively). The recovery of neuromuscular function was significantly improved, as shown by quantitative electromyography and sensorimotor tests. Clinical signs of recovery evaluated with toe spreading reflex appeared earlier in hexa group than in control animals. Electrophysiological recordings were performed each 3 days during 34 days following nerve injury. Higher values of the compound muscle action potential (CMAP) were obtained in hexa-treated animals that correspond to an improved regeneration. Moreover, hexa induced a significantly faster regeneration rate (hexa: 2.87 +/- 0.15 mV/day; control: 2.00 +/- 0.06 mV/day), as measured by the slope of CMAP increase (44% enhancement). A morphometric analysis performed 7 days following crush showed an increased number of regenerating fibers, as well as increased diameter and thickness of the myelin in hexa-treated mice. Thus, hexa increased the regeneration of both sensory and motor axons in lesioned nerve, leading to an improved functional recovery. (C) 1996 Academic Press, Inc.