Epidural perfusion cooling protects against spinal cord ischemia in rabbits

Abstract

The protective effect of regional epidural spinal cord cooling was evaluated in a rabbit spinal cord ischemia model. Hypothermia was performed by the continual perfusion of 2-4 degrees C cold saline in the epidural space around the ischemic lumbar segments, 4 min before and during ischemia. The spinal cord was deeply hypothermic (21 degrees C) throughout the whole ischemic period. Ischemia was induced by the occlusion of the abdominal aorta for 40 min under normothermic or hypothermic conditions. Recovery of motor and sensory functions, spinal cord-evoked potentials, and motor-evoked potentials were then evaluated up to 24 h postischemia. After this period, choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were measured, in particular, zones of the lumbar spinal cord. AChE was also investigated histochemically. Animals in the normothermic group displayed fully developed spastic paraplegia with near complete loss of spinal somatosensory and motor-evoked potentials. AChE histochemistry showed extensive necrotic changes affecting lumbosacral gray matter. These changes corresponding with the pronounced losses of ChAT and AChE activities indicated irreversible injury of the spinal cord. In contrast, after hypothermic ischemia, animals survived without any sign of neurological impairment with almost full recovery of the spinal cord-evoked potentials. ChAT and AChE activities in the gray matter showed near control values corresponding with histochemical analysis of fully preserved gray matter. Hypothermia under the present experimental conditions efficiently protected the spinal cord against ischemic injury.

Epidural cooling for the prevention of ischemic injury to the spinal cord during aortic occlusion in a rabbit model: Determination of the optimal temperature

“…Core body temperature, intracranial pressure, and arterial blood pressure in rabbits during 40 minutes of aortic occlusion and epidural cooling at various temperatures (mean ± standard error of mean) cooling of the spinal cord to 21°C with an aortic occlusion of 40 minutes. 25 However, EC is not without limitation. High EC fluid flow may be necessary for the maintenance of the desired level of hypothermia resulting in increased CSF pressure.…”

“…), blinded for group designation, reviewed all the slides and graded the extent of ischemic changes (Table II). [23][24][25] Martelli et al 549 Statistical analysis. All the clinical data were expressed as the mean ± the standard error of the mean.…”

Protection in Animal Models of Brain and Spinal Cord Injury with Mild to Moderate Hypothermia

“…Hypothermia has been found to improve outcome in several animal models of ischemic SCI, including pigs (Colon et al, 1987;Strauch et al, 2004), rabbits (Naslund et al, 1992;Wakamatsu et al, 1999;Tetik et al, 2002), and dogs (Berguer et al, 1992;Tabayashi et al, 1993) Various new methodologies producing local cooling including epidural cooling techniques have also provided positive results (Yoshitake et al, 2007). In a study by Malatova et al (1995), an epidural cooling technique provided evidence that deep spinal cord hypothermia provided some degree of protection following a regional ischemic insult. Thus, moderate levels of cooling are protective in both traumatic and ischemic SCI models.…”

Hypothermic Treatment for Acute Spinal Cord Injury

“…In addition to trauma, various levels of hypothermia have also been shown to protect against periods of ischemia that may occur during transient periods of spinal cord compression or aortic reconstruction surgery [54][55][56][57][58][59][60][61][62][63]. In models of compression injury, hypothermia has been shown to improve neurological outcome, recovery of somatosensory evoked potentials and normal motor function [36,64].…”