The Protective Effect of Spinal Cord Stimulation Postconditioning Against Spinal Cord Ischemia/Reperfusion Injury in Rabbits

Abstract

Delayed paraplegia due to spinal cord ischemia/reperfusion injury (IRI) remains one of the most severe complications of thoracoabdominal aneurysm surgery, for which effective prevention and treatment is still lacking. The current study investigates whether spinal cord stimulation (SCS) postconditioning has neuroprotective effects against spinal cord IRI. Ninety-six New Zealand white male rabbits were randomly divided into four groups as follows: a sham group and three experimental groups (C group, 2 Hz group, and 50 Hz group) n = 24/group. Spinal cord ischemia was induced by transient infrarenal aortic balloon occlusion for 28 min, after which rabbits in group C underwent no additional intervention, while rabbits in the other two experimental groups underwent 2 Hz or 50 Hz epidural SCS for 30 min at the onset of reperfusion and then daily until sacrifice. Hind limb neurologic function of rabbits was assessed using Jacob scale. Lumbar spinal cords were harvested immediately after sacrifice for histological examination and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. The number of viable α-motor neurons in ventral horn was counted and TUNEL-positive rate of α-motor neurons was calculated. Spinal cord IRI was caused by transient infrarenal aorta occlusion for 28 min. Both 2 Hz and 50 Hz SCS postconditioning had neuroprotective effects, particularly the 2 Hz SCS postconditioning. Comparing to C group and 50 Hz group, rabbits in the 2 Hz group demonstrated better hind limb motor function and a lower rate of TUNEL-positive α-motor neuron after eight hours, one day, three days, and seven days of spinal cord reperfusion. More viable α-motor neurons were preserved after one and three days of spinal cord reperfusion in 2 Hz group rabbits than in C group and 50 Hz group rabbits. SCS postconditioning at 2 Hz protected the spinal cord from IRI.