局部亚低温对脑出血后水肿影响的实验研究

Effect of local mild hypothermia on edema following intracerebral hemorrhage in rats

目的探讨局部亚低温对大鼠脑出血后水肿形成的影响及其可能机制。方法雄性Wistar大鼠230只随机分为：对照组；脑出血组；脑出血加局部亚低温组；凝血酶加局部亚低温组。应用Evans—Blue测定血脑屏障（BBB）通透性，应用干湿重法测定脑水含量。结果与对照组相比，大鼠注血后6h开始出现脑组织水含量和BBB通透性的增加，在72h达到高峰，然后逐渐消退。不同时程局部亚低温均可以显著降低脑出血后72h时脑组织水含量及BBB通透性（尸〈0.01），其中给以4h局部亚低温时，降低最明显。注射凝血酶6h后，脑组织水含量及BBB通透性显著增高（P〈0.01），于24～48h达高峰，然后逐渐下降。凝血酶＋局部亚低温组在各个时间点与凝血酶组相比，脑组织水含量及BBB通透性明显降低（P〈0.01）。结论局部亚低温可能是通过抑制凝血酶的毒性作用来减轻脑出血后水肿的形成及血脑屏障的破坏。

Objective To explore the effect of local mild hypothermia（LMH） on the edema formation following intracerebral hemorrhage in rats. Methods 230 male Wistar rats were randomly divided into 5 groups ：the control group, the intracerebral hemorrhage （ICH） group, the ICH ＋ LMH group, the thrombin （T） group, the T ＋ LMH group. Brain water content （BWC） was determined by dry-wet weight method and the permeability of BBB was measured by Evans-Blue extravasion. Results BWC and BBB permeability were increased at 6h after autologous arterial blood injection,both peaked at 72h,and then declined. At 72h after injection,both BWC and BBB permeability decreased after lh,2h,4h,6h or 8h LMH（P〈0.01）. The effect of 4h LMH was best. After thrombin injection ,BWC and BBB permeability increased at 6h（P〈0.01） ,peaked at 24h ,lasted until 48h and then declined. At all time points,BWC and the permeability of BBB were decreased with 4h LMH given right after the injection of thrombin（P〈0.01）. Conclusions LMH can decrease BWC and the permeability of BBB following ICH. The effect maybe due to that the LMH can inhibit the toxicity of thrombin to brain.