Induction of glial cell line-derived neurotrophic factor and c-ret porto-oncogene-like immunoreactivity in rabbit spinal cord after transient ischemia

Abstract

The mechanism of spinal cord injury has been thought to be related with tissue ischemia, and spinal motor neuron cells are suggested to be vulnerable to ischemia. To evaluate the mechanism of such vulnerability of motor neurons, we attempted to make a reproducible model of spinal cord ischemia. Using this model, the inductions of glial cell line-derived neurotrophic factor (GDNF) and the c-ret porto-oncogene (RET) receptor tyrosine kinase were investigated with immunohistochemical analyses for up to 7 days of the reperfusion following 15 min of ischemia in rabbit spinal cord. Spinal cord sections from animals sacrificed at 8 h, 1, 2, and 7 days following the 15 min of ischemia were immunohistochemically evaluated using monoclonal antibodies for GDNF and RET. Following the 15 min of ischemia, the majority of the motor neurons showed selective cell death at 7 days of reperfusion. Immunoreactivity of GDNF and RET were induced at 8 h of reperfusion selectively in motor neuron cells. No glial cells were stained in the spinal cord sections. The induction of GDNF and RET proteins at the early stage of reperfusion may be related to the transient functional recovery of neurons after ischemia.