An Morphological Study on the Alteration of Immunoreactivity of the Neural Cell Adhesion molecule ( NCAM ) in Rat Spinal Cord after Unilateral Sciatic Neurotomy and Reconnection

ABSTRACT

BACKGROUND: NCAM plays an important role in the peripheral innervation of the spinal neurons as well as in the development of the CNS. Although expression of NCAM is down-regulated in most areas of adult brain and spinal cord, it could be reexpressed after neuronal damages induced by various physical or chemical insults including peripheral nerve transection. METHOD: To investigate alterations of the NCAM immunoreactivity in the dorsal and ventral horns of the spinal cord induced by peripheral neurotomy and reconnection, the unilateral sciatic nerve of the rats were transected and immediately reconnected. Experimental animals were sacrificed at 1 week and 3 weeks after operation, and the alteration of NCAM immunoreactivity in the ventral and the dorsal horns of the lower lumbar spinal cord were examined. RESULTS: NCAM-immunoreactive astrocytes in the ipsilateral dorsal horn was increased at 1 week after operation. Neurons with NCAM?immunoreactive membranes and processes were increased in ipsilateral dorsal horns, and in large motor neurons of ventral horns of both sides at 3 weeks after unilateral sciatic neurotomy and reconnection. CONCLUSIONS: It is consequently suggested that unilateral sciatic neurotomy and reconnection induce the increase of the NCAM-immunoreactive neurons and glial cells in the spinal cord, and increase of NCAM immunoreactivity in the spinal cord may reflect the neuronal damage and healing process induced by peripheral nerve injury.