Dissociation of HSP72 and HSC73 heat shock mRNA inductions after spinal cord ischemia in rabbit.

The inductions of HSP72 and HSC73 mRNAs were investigated with Northern blot and immunohistochemical analyses for up to 7 days of the reperfusion after 5 or 15 min ischemia in rabbit spinal cord. Following 15 min ischemia, HSP72 mRNA was induced at 8 h of reperfusion, while HSC73 mRNA continuously remained at the control level. Immunoreactivity of HSP72 protein was slightly induced at 8 h of reperfusion selectively in motor neurons, and the majority of motor neuron showed selective cell death at 7 days of reperfusion. This study demonstrated selective induction of HSP72 mRNA and the protein in motor neuron cells that eventually showed selective delayed neuronal death after transient ischemia in the spinal cord. This phenomenon was not accompanied by HSC73 induction.