脑缺血-再灌注大鼠P-选择素的表达和髓过氧化物酶活性变化的研究

Expression of P-selectin and myeloperoxidase activity changes in focal cerebral ischemia reperfusion injury in rats

目的探讨脑缺血再灌注损伤不同缺血区域的炎症反应。方法将雄性Wistar大鼠85只,随机分为脑缺血再灌注组(70只)和假手术组(15只)。前者用线栓法建立局灶性脑缺血再灌注模型,脑缺血90min再灌注,将大鼠随机分为7个时间点,分别是再灌注后3、6、12、24、48、72和96h,每个时间点10只大鼠。采用免疫组化法和生化法,观察额顶部皮质和基底核区P选择素表达、髓过氧化物酶(MPO)活性变化。结果①再灌注后缺血侧微血管内皮细胞表面出现P选择素表达,主要分布于额顶部皮质和基底核区:3h额顶部皮质为(13±4)支,基底核区为(11±3)支;12h额顶部皮质为(60±6)支,基底核区为(57±5)支;72h额顶部皮质为(19±4)支,基底核区为(16±4)支。②再灌注后12、24、48、72和96h各时间点MPO活性:额顶部皮质分别是(0.206±0.029)U/g、(0.421±0.030)U/g、(0.369±0.022)U/g、(0.341±0.023)U/g和(0.328±0.028)U/g;基底核区分别是(0.183±0.013)U/g(0.292±0.017)U/g(0.340±0.012)U/g(0.226±0.018)U/g、(0.158±0.022)U/g。假手术组MPO活性:额顶部皮质为(0.033±0.005)U/g、基底核区为(0.031±0.004)U/g,比再灌注组低(P<0.05)。基底核区的MPO活性在再灌注48h达到高峰后下降。额顶部皮质MPO活性在再灌注24h达到高峰后至96h仍维持较高水平。结论脑缺血再灌注损伤时,存在主动炎症反应:出现P选择素表达和中性粒细胞浸润,额顶部皮质比基底核区的炎症反应更强烈和持久。

Objective To study the inflammatory, reaction in different ischemic area after focal cerehral ischemia-reperfusion injury in rats. Methods 85 male Wistar rats were randomly assigned into isehemia-reperfusion group （70） and sham operation group （ 15 ）. The focal middle cerebral artery occlusion （ MCAO ） model was made by inserting a suture. Repeffusion was made 90 minutes after MCAO. The expression of P-selectin and the Myeloperoxidase （MPO） aetivlty were investigated in the frontal and parietal cortex and basal ganglia with immunohistochemistry at different time points 3, 6, 12, 24, 48, 72, 96h after repeffusion. HE and TFC staining was also made. Results ①Expression of P-seleetin was showed on isehemic endothelium, mainly in the ischemie frontal and parietal cortex and basal ganglia. At 3 h, 13 ± 4 vessels with P-seleetin expression were found in the frontal and parietal cortex, 11 ± 3 in basal ganglia; there were 60 ± 6 and 57 ± 5 in these two areas at 12 h respectively. And 19 ± 4, 16 ± 4 at 72h.② MPO activity was showed （0.206 ± 0.029） U/g, （0.421 ± 0.030） U/g,（0.369 ±0.022） U/g, （0.341 ±0.023） U/g and （0.328±0.028） U/g at 12, 24, 48,72 and 96h respectively in the frontal and parietal cortex, while （0. 183 ± 0. 013 ） U/g, （0. 292 ± 0. 017） U/g, （0.340 ±0.012）U/g, （0.226 ±0.018） U/g and （0. 158 ±0.022） U/g in hasal ganglia respectively in ischemia-reperfusion group. Thes were higher than control group （P 〈 0. 05 ）. In ischemic hasal ganglia, MPO activity peaked at 48h, gradually descended afterwards. In the frontal and parietal cortex, MPO activity peaked at 24h, and remained elevated until 96h. Conclusion There is inflammatory reaction after cerebral ischemiua-reperfusion injury.P-selectin is expressde,and neutrophils infiltration.The inflammation is more persistent and intensive in sichemic frontal and parietal cortex than the basal ganglia.