脂氧素A4后处理对大鼠全脑缺血再灌注时细胞凋亡的影响

Effect of iipoxin A4 postconditioning on cell apoptosis following global cerebral ischemia-reperfusion in rats

目的评价脂氧素A4时处理对大鼠全脑缺血再灌注时细胞凋亡的影响。方法雄性成年sD大鼠180只，体重200～250g，采用随机数字表法，将其分为3组：假手术组（S组）、缺血再灌注组（I／R组）和脂氧素A4后处理组（L组）。I／R组和L组采用四血管阻塞法建立大鼠全脑缺血再灌注损伤模型。L组于再灌注即刻侧脑室注射脂氧素A4100ng（用生理盐水稀释至5μl），s组和I／R组侧脑室注射生理盐水5μl。分别于再灌注2、6、12、24和72h时，处死6只大鼠，取脑组织，行HE染色，光镜下观察病理学结果，采用免疫组化法测定海马CA1区caspase-3表达。分别于再灌注2、6、12、24和72h时，处死6只大鼠，取海马组织，采用流式细胞仪检测细胞凋亡率。结果与s组比较，I／R组和L组再灌注各时点海马CA1区caspase-3表达上调，海马组织细胞凋亡率升高（P〈0．01）；与I／R组比较，L组再灌注各时点海马CA1区caspase-3表达下调，海马组织细胞凋亡率降低（P〈0．01），病理学损伤减轻。结论脂氧素A4后处理减轻大鼠全脑缺血再灌注损伤的机制与下调caspase-3表达，减少细胞凋亡有关。

Objective To evaluate the effect of lipoxin A4 postconditioning on the cell apoptosis following global cerebral ischemia-reperfusion （I/R） in rats. Methods One hundred and eighty healthy male Sprague-Daw- ley rats, weighing 200-250 g, were randomly divided into 3 groups （ n = 60 each） ： sham operation group （group S）, global cerebral I/R group （group I/R） and lipoxin A4 postconditioning group （group L）. Global cerebral I/R was produced by 4-vessel occlusion method in anesthetized rats. Lipoxin A4 100 ng （in 5 μl normal saline） was in- jected into the lateral cerebral ventricle at tbe beginning of reperfusion in group L, while the equal volume of nor- mal saline was given instead in groups S and I/R. Six rats were sacrificed at 2, 6, 12, 24 and 72 h of reperfusion and their brains were removed and cut into sections which were stained with haematoxylin and eosin for examination of pathological changes. The expression of caspase-3 in hippocampal CA1 region was detected. Six rats were sacri- ficed at 2, 6, 12, 24 and 72 h of reperfusion and hippocampi were removed for detection of cell apoptosis. The apoptosis rate was calculated. Results Compared with group S, the expression of caspase-3 in hippocampal CA1 region was significantly up-regulated, the apoptosis rate was increased at each time point of reperfusion in groups I/R and L （P 〈 0.01） . Compared with group I/R, the expression of caspase-3 in hippocampal CA1 region was significantly down-regulated, and the apoptosis rate was decreased at each time point of reperfusion （P 〈 0.01 ）, and the pathological changes were significantly reduced in group L. Conclusion The mechanism by which lipoxin A4 postconditioning ameliorates global cerebral I/R injury is related to down-regulation of caspase-3 expression andreduction of cell apoptosis in rats.