Immediate ischemic preconditioning based on somatosensory evoked potentials seems to prevent spinal cord injury following descending thoracic aorta cross-clamping

Abstract

Objective: Delayed ischemic preconditioning has demonstrated neuroprotective effects in spinal cord ischemia. We investigated the effects of immediate ischemic preconditioning based on somatosensory evoked potentials monitoring in a model of spinal cord injury due descending thoracic aorta occlusion in dogs. Methods: Twenty-one dogs were submitted to spinal cord ischemia induced by descending thoracic aorta crossclamping for 45 min. Control group underwent only the aortic cross-clamping (nZ7), group A underwent one cycle of ischemic preconditioning (nZ7) and group B underwent three equal cycles of ischemic preconditioning (nZ7), immediately before the aortic cross-clamping. Ischemic preconditioning cycles were determined by somatosensory evoked potentials monitoring. Neurologic evaluation was performed according to the Tarlov score at 72 h of follow-up. The animals were then sacrificed and the spinal cord harvested for histopathology. Results: Aortic pressures before and after the occluded segment were similar in the three groups. Ischemic preconditioning periods corresponded to a mean ischemic time of 3G1 min and a mean recovery time of 7G2 min. Severe paraplegia was observed in three animals in Control group, in four in group A and in none in group B. Tarlov scores of group B were significantly better in comparison to the Control group (PZ0.036). Histopathologic examination showed severe neuronal necrosis in the thoracic and lumbar gray matter in animals who presented paraplegia. Conclusions: Immediate repetitive ischemic preconditioning based on somatosensory evoked potentials monitoring seems to protect spinal cord during descending aorta cross-clamping, reducing paraplegia incidence.

The effect of exercise and oxidant–antioxidant intervention on the levels of neurotrophins and free radicals in spinal cord of rats

“…14 Mildly, oxidant-challenged cells increase their viability through complex adaptations, that result in maintained physiological functions that induce adaptations in normal cell populations. 15 The strong tendency of lower FR concentrations suggests a preconditioning effect of exercise vs H 2 O 2 . 1 N-tert butyl-a-phenyl nitrone is reported to have multiple pharmacological activities to reduce ROS, including the ability to trap alkoxyl radicals, superoxide radicals and hydroxyl radicals and to decrease inducible cytochrome (cyclooxygenase-2), as well as to inhibit nuclear factor-kB transduction.…”

Heat shock proteins HSP70 and HSP27 in the cerebral spinal fluid of patients undergoing thoracic aneurysm repair correlate with the probability of postoperative paralysis

“…Hart et al Cizkova et al 2004) showed a robust induction of HSPs with 6 and 12 min of spinal cord ischemia in a microarray analysis. Contreras (Contreras et al 2005) demonstrated spinal cord protection using immediate ischemic pre-conditioning guided by SSEP measurements but did not measure HSPs as a part of this study. Robinson et al (2005) showed an increase in HSP70 in response to ischemia in motoneurons, which reduced damage.…”

Effect of ischemic post-conditioning on spinal cord ischemic-reperfusion injury in rabbits

“…Interestingly, the preconditioning itself would induce no harm to the tissues, since the results in the IPC group were not significantly different from the results in group C, an observation similar to that observed by Iliodromitis et al 20 Another possible explanation for the absence of neuroprotection in the IPC group of our study is that the reperfusion interval between IPC and the subsequent ischemic event was only three minutes, much shorter than that of the other "protective" IPC protocols. 18,22 Recently, Contreras et al 23 demonstrated the importance of the reperfusion interval by monitoring the somatosensory evoked potentials. Further experiments using different cycles and durations of IPC and reperfusion interval are required to address the observed between-study variances.…”