摘要
目的:脑缺血再灌注期间进行局部亚低温干预,观察其对再灌注治疗时间窗的影响并研究其机制。方法:将72只Wistar大鼠随机分为假手术组6只;大脑中动脉闭塞(MCAO)24小时组6只;常温再灌注组30只;亚低温再灌注组30只。动物均在再灌注24小时后处死,但MCAO24小时组大脑中动脉闭塞24小时后直接处死。采用TTC染色观察梗死体积,用干-湿质量法测定脑含水量,用原位末端标记(TUNEL)观察神经细胞凋亡的变化,采用免疫组化法检测大鼠模型的Bcl-2、Bax及水通道蛋白4(aquapor-in4,AQP4)的表达。结果:与脑梗死的近期结局MCAO24小时组的梗死体积、脑含水量、TUNEL阳性细胞数、及Bcl-2、Bax、AQP4的表达相比较:常温组MCAO2～3小时再灌注24小时有统计学差异(P<0.01),MCAO4～6小时再灌注24小时没有统计学差异(P>0.05);亚低温组MCAO2～4小时再灌注24小时各组有统计学差异(P<0.01);MCAO5～6小时再灌注24小时没有统计学差异(P>0.05)。亚低温再灌注组各时相点的梗死体积、脑含水量、TUNEL阳性细胞数、Bax、AQP4的表达均显著低于相应常温组,Bcl-2的表达显著高于常温组(P<0.01,P<0.05)。结论:再灌注期间实施局部亚低温可延长再灌注治疗时间窗,其机制可能与抑制Bax的表达提高Bcl-2的表达从而抑制凋亡,抑制AQP4的表达从而保护脑微循环有关。
Aim：to observe the effection of local mild hypothermia applied during reperfusion on the time window of reperfusion of blood and mechanisms of that. Methods ： The adult 72 rats were randomly divided into sham - operation group （ n = 6 ）, the middle cerebral artery thoroughly Obstructed 24 hours （ MCAO 24h ） group （ n = 6 ）, normal temperature groups （ NT, n = 30 ）, mild hypothermia（ MH, n = 30） were. The expressions of Bcl - 2, Bax , quaporin4 （ AQP4 ） were detected by immunohistochemistry. The neuronal apoptosis were dynamically detected by TUNEL. The infarct volumes were evaluated by TTc staining. The water content of rats brain tissue were detected by using dry - wet weight method. Result： Compared with MCAO 24h group as far as the infarction volume and water content of rats brain and the number of apoptotic cells and the expressions of Bcl - 2, Bax, AQP4 were con- cerned：MCAO 2 - 3h reperfusion groups of NT have significant difference （P 〈 0. 01 ）, MCAO4 -6h groups reperfusion of NT have not significant difference（P 〉 0.05 ） ; MCAO 2 - 4h reperfusion groups of MH have signif- icant difference（ P 〈 0. 01 ）. MCAO 5 - 6h reperfusiongroups of MH have not significant difference（P 〉 0. 05 ）. MH were lower significantly than NT as far as the infarction volume and water content of rats brain and the number of apoptotic cells and the expressions of Bax .AQP4 were concerned, MH were higher significantly than NT in term of Bcl - 2 （ P 〈 0. 01, P 〈 0. 05 ）. Conclusion ： The mild hypothermia applied during reperfusion can prolong the treatment time window of reperfusion therapy. The reason for that maybe it can inhibit apoptosis; it can protect brain microcirculation by depressing the exprdssion of AQP4.
关键词
再灌注期局部亚低温
再灌注
时间窗
细胞凋亡
基因BCL-2
Bax水通道蛋白4
the local mild hypothermia applied during reperfusion
time window reperfusion of blood flow
apoptosis
Gene
Bcl - 2
Bax
aquaporin4 （AQP4）
