DELAYED SELECTIVE MOTOR-NEURON DEATH AND FAS ANTIGEN INDUCTION AFTER SPINAL-CORD ISCHEMIA IN RABBITS

The mechanism of spinal cord injury has been thought to be related wit h tissue ischemia, and spinal motor neuron cells are suggested to be v ulnerable to ischemia. To evaluate the mechanism of such vulnerability of motor neurons, we attempted to make a reproducible model for spina l cord ischemia. Using this model, cell damage was histologically anal yzed. Detection of ladders of oligonucleosomal DNA fragment was invest igated with gel electrophoresis up to 7 days of the reperfusion. Time course expression of Fas antigen, identified as a apoptosis-regulating molecules, was also assessed in rabbit spinal cord following transien t ischemia. Spinal cord sections from animals sacrificed at 8 h, 1 day , 2 days, and 7 days following 15-min ischemia were immunohistochemica lly evaluated using monoclonal antibodies for Fas antigen. Following 1 5-min ischemia, the majority of motor neuron showed selective cell dea th at 7 days of reperfusion. Typical ladders of oligonucleosomal DNA f ragments were detected at 2 days of reperfusion. Immunoreactivity of F as antigen were induced at 8 h to 1 day of reperfusion selectively in motor neuron cells. The expression of Fas antigen may be related to th e activation of apoptosis signal in motor neuron cells after spinal co rd ischemia in rabbits. (C) 1998 Elsevier Science B.V. All rights rese rved.