Induction of Parkinson disease-related proteins in motor neurons after transient spinal cord ischemia in rabbits

The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells against ischemia. However, the mechanisms of such vulnerability are not fully understood. We investigated a possible mechanism of neuronal death by immunohistochemical analysis for DJ-1, PINK1, and α-Synuclein. We used a 15-min rabbit spinal cord ischemia model, with use of a balloon catheter. Western blot analysis for DJ-1, PINK1, and α-Synuclein; temporal profiles of DJ-1, PINK1, and α-Synuclein immunoreactivity; and double-label fluorescence immunocytochemical studies were performed. Western blot analysis revealed scarce immunoreactivity for DJ-1, PINK1, and α-Synuclein in the sham-operated spinal cords. However, they became apparent at 8 h after transient ischemia, which returned to the baseline level at 1 day. Double-label fluorescence immunocytochemical study revealed that both DJ-1and PINK1, and DJ-1 and α-Synuclein were positive at 8 h of reperfusion in the same motor neurons, which eventually die. The induction of DJ-1 and PINK1 proteins in the motor neurons at the early stage of reperfusion may indicate oxidative stress, and the induction of α-Synuclein may be implicated in the programmed cell death change after transient spinal cord ischemia.