Induction of ischemic tolerance by remote perconditioning or postconditioning as neuroprotective strategy for spinal cord motor neurons

Aims: The study is focused on the investigation of the mechanisms leading to ischemic tolerance acquisition in the spinal cord neurons via application of non-invasive method of remote conditioning. Material and methods: We have verified the possibility of neuroprotection of spinal cord in rabbit by using remote perconditioning (PerC) applied during last 12 min of spinal cord ischemia (SC-ischemia) or postconditioning (PostC) applied after 1st (early) or 3rd (late) h of reperfusion. Spinal cord ischemia was induced by occlusion of the aorta below the left renal artery for 20 min. Reperfusion period was 24 or 72 h. Remote conditioning was induced by compression of left forelimb with a tourniquet in 3 cycles of 2 min of ischemia, each followed by 2 min of reperfusion. Damaged neurons were detected by Fluoro Jade B method and the modified Tarlov score was used for functional assessment. Key findings: The remote conditioning significantly attenuated degeneration of motor neurons in all remote conditioned groups versus both SC-ischemia groups. We detected significant changes in number of Hsp70 positive motor neurons. At 72time point, in the group with remote late PostC we observed significant increase (p < 0.001) of Hsp70 positive motor neurons versus SC- ischemia group and sham control. There was a trend towards improvement of hindlimbs movement. Significance: This study showed the effectiveness of remote conditioning as a neuroprotective strategy, evidenced by induction of ischemic tolerance leading to decrease of motor neuron degeneration.

Automated summary

The study demonstrated the effectiveness of remote conditioning in reducing degeneration of spinal cord motor neurons and increasing the number of Hsp70 positive neurons. Late remote postconditioning showed the most significant neuroprotective effect at the 72-hour time point.