急性缺血性脑卒中患者白细胞粘附分子的表达及细胞内[Ca^(2+)]变化的实验研究

Study on the expression of adhesion molecules and cytosolic [Ca^(2+)] in peripheral blood leukocytes of the patients with acute ischemic stroke

目的探讨急性缺血性脑卒中患者外周血白细胞计数和粘附分子表达的变化,以及与中性粒细胞激活密切相关的细胞内游离钙离子浓度[Ca2+]变化,以期为脑卒中的发病机理和治疗提供有价值的理论依据。方法采用流式细胞术(FCM)检测白细胞粘附分子的表达及细胞内[Ca2+]的变化。结果脑卒中急性发作时,患者主要是中性粒细胞数增高明显,外周血白细胞CD11b、CD18的表达在发病24h内升高,同时,脑卒中患者中性粒细胞表面CD62L的表达在急性期明显降低,急性脑卒中患者中性粒细胞内[Ca2+]增加,中性粒细胞表面粘附分子CD11b、CD18的表达与细胞内[Ca2+]具有正相关性,CD62L的表达与[Ca2+]虽无明显的线性相关性,但随着[Ca2+]的增加,CD62L的表达具有下降的趋势。结论急性脑卒中发生时,白细胞被激活,粘附分子CD11b、CD18表达上调,介导白细胞与内皮细胞粘附增强,可能会加重缺血后迟发性神经元死亡的病理生理过程。同时,随着中性粒细胞的激活,细胞表面粘附分子CD62L的表达显著下调,细胞内[Ca2+]增加,在白细胞与内皮细胞的粘附过程中起重要作用。

Objective To investigate changes in leukocyte counts,[Ca^2＋ ] and expressions of adhesion molecules（CD11b,CD18,CD62L） in peripheral blood leukocytes in patients with acute ischemic stroke. The results of this study will provide useful information for improving the understanding of the pathogenesis of cerebral stroke and its treatment. Methods The expression of adhesion molecules in leukocytes and polymorphonuclear leukocyle（PMN） cytosolic F Ca2＋] were examined using flow cytometry（FCM）. Results When acute cerebral stroke occured, leukocyte counts, mainly neutrophil counts, increased significantly in peripheral blood. The increase of PMN CD11b, CD18 in peripheral blood occured within 24h after the stroke. Down-regulation of CD62L on neutrophils was found on patients suffering from acute stroke. PMN cytosolic [Ca^2＋] was upregulated when acute stroke occured, the positive correlations were found between the expression of adhesion molecules （CD11b,CD18 on the neutrophils and PMN cytosolic [Ca^2＋]. The expression of CD62L was downregulated with the increase of [Ca^2＋], but no significant correlations were found. Conclusion These results indicate that the expression of CD11b,CD18on leukocytes increases in acute ischemic damage, thus adhesion of leukocytes and endothelial cells obviously increases. This change may aggravate post-ischcmic delayed neuronal death. Meantime, with the activation of neutrophils, the expression of CD62L on the neutrophils is significantly downregulated and PMN cytosolic [Ca^2＋ ] increases. These may have great effect on the adhesion of leukocytes and endothelial cells.