척수 손상 백서에서 MK801 투여가 체성감각 유발전위 및 척수 조직에 미치는 효과

The Effect of MK801 on SSEP and Patholoy in Chronic Spinal Cord Injured Rat

Objectives : This study was undertaken to investigate the effect of noncompetitive NMDA receptor blocker, MK801 on motor recovery, SSEP and pathology in spinal cord injured rat. Methods : The effects of MK801 on neuronal function protection, SSEP, and pathology were measured on spinal cord injury rats which were divided into 6 groups according to dose, time of drug delivery and magnitude of injury. Spinal cord injury was made with the magnitude of 25gm-cm and 50gm-cm on 42 rats. BBB locomotor function test was performed to evaluate the motor power recovery in hindlimb for 2 weeks after injury. After motor function test was completed, SSEP was measured. Amplitude and latency of the P1, N1 peak was measured and compared between groups. Finally rats were sacrificed, and pathologic findings including measurement of area of necrotic cord were studied and compared between groups. Results : Motor recovery at 2 weeks was better in MK801 group comparing to saline control group. SSEP at 2 weeks showed no difference in N1, P1 latencies, but significantly greater amplitude in MK801 group, compared to saline control group. On light microscope, there was no specific histologic differences between experimental groups. The cystic necrotic area in coronal plane was measured and compared in each group. The necrotic area was significantly smaller in MK801 1mg/kg group(delivered after injury) than vehicle group. The necrotic area in MK801 5mg/kg group and MK801 1mg/kg group(delivered before injury) was smaller than vehicle group even though it was not statistically significant. Conclusion : From the above result, it is speculated that NMDA blocker, MK801 can improve impaired neuronal function in spinal cord injury.