Evaluation of Neuroprotective Effects of Local Hypothermia in a Porcine Spinal Cord Injury Model

Abstract The goal of this study was to assess the therapeutic potential of a 5-hour local spinal cord (SC) hypothermia by 4 °C saline on preservation of SC tissue at the injury epicentre and 3 cranial and caudal 10 mm long SC segments in a porcine experimental model of spinal cord injury (SCI). The SCI was inflicted through L3 laminectomy by a metallic rod moved by a velocity of 30 mm.sec −1 , and operated by a computer-controlled apparatus. A group of 15 female minipigs 5‒8-month-old weighing 28‒35 kg was randomly divided into 5 subgroups (each composed of 3 animals): 1) sham controls; 2) SCI by force 8N; 3) SCI by force 8N, 5-hour hypothermia; 4) SCI by force 15N; 5) SCI by force 15N, 5-hour hypothermia. After a 9-week survival period, the minipigs were in deep general anaesthesia transcardially perfused by 5000 ml of saline and fixed by 5000 ml 4 % neutral paraformaldehyde. White and grey SC matter damage was evaluated in specimens cut from the epicentre of injury as well as 3 cranial and 3 caudal 10 mm long SC blocks dyed according to Luxol fast blue (LFB) with cresyl violet (CV) protocol for light microscopic observations. The percentage of preserved SC white and grey matter was assessed in microphotographs and compared with data from sham controls (considered 100 %). The data were statistically evaluated by ANOVA test, the difference P ˂ 0.05 was considered significant. Results of the study suggest that 5-hour local cooling of the epicentre of SCI is well tolerated and facilitates the preservation of SC tissue integrity. Additional experimental and preclinical studies are necessary before introducing the method in practice.