BENEFICIAL-EFFECTS OF THE MELANOCORTIN ALPHA-MELANOCYTE-STIMULATING HORMONE ON CLINICAL AND NEUROPHYSIOLOGICAL RECOVERY AFTER EXPERIMENTAL SPINAL-CORD INJURY

OBJECTIVE: Melanocortins, peptides related to melanocyte-stimulating h ormone (MSH) and corticotropin (ACTH), exhibit neurotrophic and neurop rotective activity in several established models of peripheral and cen tral nervous system damage. The beneficial effects of melanocortins on functional recovery after experimental brain damage and central demye linating diseases have prompted us to investigate alpha MSH treatment in a weight drop model of traumatic spinal cord injury in rats. METHOD S: In two independent randomized blinded experiments, treatment with e ither alpha MSH (75 mu g/kg of body weight administered subcutaneously every 48 h for 3 weeks after trauma) or single high-dose (30 mg/kg, 3 0 min after injury) methylprednisolone was compared with saline treatm ent in rats subjected to a moderately severe 20-gcm weight drop injury . Spinal cord function was monitored using behavioral, electrophysiolo gical, and histological parameters. RESULTS: In both experiments, alph a MSH significantly improved recovery, as illustrated by Tarlov scores , thoracolumbar height, and amplitude of rubrospinal motor evoked pote ntials. The magnitude of the alpha MSH effect on motor performance was comparable with the one observed after treatment with methylprednisol one. CONCLUSION: The reproducible neurological and electrophysiologica l improvement in spinal cord function of animals treated with alpha MS H suggests a new lead in the treatment of traumatic spinal cord injury .