INVOLVEMENT OF AN INTERCELLULAR-ADHESION MOLECULE 1-DEPENDENT PATHWAYIN THE PATHOGENESIS OF SECONDARY CHANGES AFTER SPINAL-CORD INJURY IN RATS

The intercellular adhesion molecule 1 (ICAM-1) plays an important role in immune responses by promoting infiltration of neutrophils into tis sues; however, its implication in the secondary destructive pathomecha nism after the initial mechanical injury to the spinal cord has not be en clarified yet. This study was conducted to examine the role of ICAM -1 in this process after spinal cord injury (SCI) in rats. The express ion of ICAM-1 mRNA was investigated by the reverse transcription-PCR m ethod and the effect of monoclonal antibody (mAb) to ICAM-1 on SCI was evaluated by measuring various parameters. ICAM-1 mRNA expression cor related with the severity of injury and reached its maximum level 6 h after SCI. Intravenous injection of ICAM-1 mAb (1 mg/kg) 30 min after SCI reduced motor disturbance and enhanced recovery. Moreover, it sign ificantly suppressed myeloperoxidase activity by 43.0% and spinal cord edema by 1.1% in the injured spinal cord tissue, The posttraumatic dr op in spinal cord blood flow was also improved. These results suggest that ICAM-1 is deeply involved in the secondary self-destructive proce ss after mechanical injury of the spinal cord and should be an effecti ve target for developing a pharmacological treatment for SCI.