Local Mild Hypothermia Therapy In Acute Cerebrovascular Disease Experimental And Clinical Studies

Objective To investigate the therapeutic effects of local mild hypothermia on the acute cerebral ischemia and reperfusion damage in rats. Methods A pathological model of cerebral ischemia reperfusion damage in rats without craniectomy was developed referring to Koizumi and Longa's method. The controlled study of normal thermia and local mild hypothermia was performed between the permanent focal cerebral ischemia group and ischemia-reperfusion group. Results In Expt.1(Permanent focal cerebral ischemia).Normothermia:animals maintained at 37.1～37.5℃ brain were exposed to 3h ischemia,then were sacrificed,the infarct volume was 124.9±13.4mm3.Hypothermia: the average infarct volume was 34.4±7.7mm3 after local mild hypothermia(32～33℃) treatment for 3 hours followed 10min ischemia (P=0.002).A significant reduction of infarct volume of hypothermia group was seen as compared to normothermia; the average infarct volume was 111.9±14.0mm3 after local mild hypothermia treatment for 3 hours followed 1h ischemia (P=0.17), no obvious difference of the infarct volume was observed between normothermic rats and hypothermic rats. In Expt.2(transient focal cerebral ischemia).Normothermia:animals were maintained at 37.1～37.5℃ during ischemia and reperfusion,then were sacrificed after 2h and 20min of reperfusion, the average infarct volume was 58.5±8.6mm3.Hypothermia: The average infarct volume was 24.1±7.7mm3 after local mild hypothermia(32～33℃) treatment for 2h and 20min followed 40min ischemia (P=0.002).The infarct volume reduced significantly in the mild hypothermia group compared to normothermia. Conclusions It was effective that cerebral ischemia was treated with local mild hypothermia in the time-window, which exertedan obvious action on cerebral protection. Local mild hypothermia could decrease the volume of cerebral infarct, reperfusion following local ischemia for 40 minutes.