Local hypothermia and optimal temperature for stroke therapy in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Local hypothermia induced by intravascular infusion of cold saline solution effectively reduces brain damage in stroke. We further determined the optimal temperature of local hypothermia in our study.</p><p><b>METHODS</b>Seventy-eight adult male Sprague Dawley rats (260 - 300 g) were randomly divided into 3 groups: group A, ischemia/reperfusion without cold saline infusion (n = 26) (control group); group B, infusion with 20 degrees C saline before reperfusion (n = 26); group C: infusion with 10 degrees C saline before reperfusion (n = 26). In each group, we chose 15 rats for monitoring physical indexes and the temperature of the brain (cortex and striatum) and body (anus), measurement of brain infarction volume, assessment of neurological deficits and the survival rate of reperfusion at 48 hours. Another 8 rats from each group was chosen for examining brain edema, another 3 from each group for histological observation by electron microscopy (EM) and light microscopy (LM) at 48 hours after reperfusion.</p><p><b>RESULTS</b>There was no significant difference among the 3 groups for physical indexes during the examination (F((2, 45)) = 0.577, P = 0.568; F((2, 45)) = 0.42, P = 0.78 for blood pressure and blood gas analysis, respectively). The brain temperature was significantly reduced in the group C compared to the other groups (F((2, 45)) = 37.074, P = 0.000; F((2, 45)) = 32.983, P = 0.000, for cortex and striatum temperature respectively), while the difference in rectal temperature between group A and B or C after reperfusion was not significant (F((2, 45)) = 0.17115, P = 0.637). And the brain infarct volume was significantly reduced in group C (from 40% +/- 10% in group A, 26% +/- 8% in group B, to 12% +/- 6% in group C, F((2, 45)) = 43.465, P = 0.000) with the neurological deficits improving in group C (chi(2) = 27.626, P = 0.000). The survival rate at 48 hours after 10 degrees C and 20 degrees C saline reperfusion was increased by 132.5% and 150%, respectively, as compared to the control group (chi(2) = 10.489, P = 0.005). The extent of the brain edema showed no significant difference (F((2, 21)) = 0.547, P = 0.587) after cold saline infusion compared to the control group. No obvious vascular injury was found by electron or light microscopy in either infusion group.</p><p><b>CONCLUSIONS</b>Regional hypothermia with 10 degrees C cold saline infusion can significantly decrease the infarction volume, improve the neurological deficits, and 10 degrees C seems to be the optimal temperature in inducing a cerebral protection effect during stroke. This procedure could be adopted as a further treatment for acute stroke patients.</p>

Anesthesia selection in the establishment of the model of middle cerebral artery occlusion in rats / 中国脑血管病杂志

Objective: To study the effect of intraperitoneal injection anesthesia and endotracheal anesthesia during creating a rat model of middle cerebral artery occlusion (MCAO). Methods: Rats were anesthetized and maintained respectively with chloral hydrate by intraperitoneal injection and inbreathing 2% halothane and 30% O2 via tracheal intubation. MCAO model was created by method of Zea Longa. The time of induction, maintenance, recovery and physiological indexes were monitored, and the result of blood gas analyses, blood glucose, brain temperatures, rectal temperatures, neurological deficit, 48 hours' survival rate and the volume of brain infarction were also studied. Results: Intraperitoneal injection anesthesia inhibited the respiration significantly. Blood gas analysis indicated serious respiratory acidosis (pH 7.29 ± 0.03, PCO2 56.8 ± 4.2 mm Hg, PO2 119.1 ± 15.6 mm Hg). But it appeared approximately normal in rats with halothane anesthesia (pH 7.48 ± 0.06, PCO2 36.2 ± 0.3 mm Hg, PO2 219.1 ± 27.4 mm Hg). There was significant difference between two kinds of anesthesia in pH, PCO2, PO2 (all P 0.05). There was no significant difference of survival rate at 48 hours and brain infract volume between the two kinds of anesthesia (P > 0.05). Conclusion: This study suggestes that endotracheal anesthesia with 2% halothane and 30% O2 is better than intraperitoneal injection of chloral hydrate. It is effective and less influence on the brain temperature and other relative indexes during creating middle cerebral artery ocelusion rat model.