S-100 beta stimulates neurite outgrowth in the rat sciatic nerve grafted with acellular muscle transplants

S-100 beta promotes neurite extension in vitro and motoneuron survival in the chicken embryo. We demonstrate here that local administration of S-100 beta stimulates the sciatic nerve regeneration into acellular muscle grafts. Normally there is a 8-10 day delay in the regeneration of axons into such grafts. Local administration of S-100 beta (0.5-1.0 mu g/h) significantly stimulated regeneration into the grafts. In S-100 beta treated grafts, the regeneration distance was increased with a factor of about 2.3 times as compared to vehicle treated grafts. The distance of regeneration was monitored with pinch test which detects sensory axons. Regenerating axons were growing outside the necrotic muscle cells as revealed with immunohistochemistry for the neurofilament Light weight polypeptide. S-100 beta demonstrated immunocytochemically in motor neurons of the rat lumbar spinal cord and in large and medium sized neurons of the dorsal root ganglia. The results suggest that S-100 beta is a physiological growth factor for peripheral nerve axons. (C) 1997 Elsevier Science B.V.