Abstract W P87: Focal Hypothermia Induced by Post-Ischemic Intra-arterial Infusion of Cold Saline Has a Neuroprotective Effect on Cerebral Ischemia Reperfusion Injury

Background and Purpose: Although the neuroprotective effect of hypothermia on cerebral ischemia is well known, the clinical application of systemic hypothermia is limited because of management problems and complications. We examined whether focal hypothermia induced by post-ischemic intra-arterial infusion of cold saline attenuates cerebral ischemia reperfusion (I/R) injury in the rat transient middle cerebral artery occlusion (MCAO) model. Methods: Male Sprague-Dawley rats were subjected to 2-hour MCAO and then were divided into three groups: 1) cold saline group (n=7) infused with 10°C saline (20ml/kg) through the recanalized internal carotid artery for 15 minutes, 2) warm saline group (n=7) infused with 37°C warm saline in the same manner as the cold saline group, and 3) control group subjected to recanalization only (n=7). After 24-hour reperfusion, all rats were tested for neurological score and then sacrificed to examine infarction, brain edema, and Evans blue leakage. Results: In the cold saline group, brain temperature at basal ganglia rapidly decreased from 37.7±0.8°C to 35.4±0.7°C and remained significantly lower than pretreatment temperatures (p<0.05) until 30 minutes after the infusion. The cold saline group showed significantly better neurological score compared with the other groups (p<0.01). Infarct volume of cold saline group (13.7±11.3%) was significantly less than that of control (42.5±8.1%) and warm saline (36.4±8.8%) group (p<0.01). Brain edema and Evans blue leakage of cold saline group was also significantly less than those of the other groups (p<0.01). Conclusions: The results of the present study suggest that focal hypothermia induced by post-ischemic intra-arterial infusion of cold saline has a neuroprotective effect on I/R injury. This therapeutic strategy is promising because of its feasibility in the clinical situation of endovascular approach.