Johns Douglas G, Ao Zhaohui, Willette Robert N, Macphee Colin H, Douglas Stephen A
Vascular Biology and Thrombosis, Cardiovascular and Urogenital Center for Excellence in Drug Discovery, 709 Swedeland Rd., UW2510, King of Prussia, PA 19406, USA.
Pharmacol Res. 2005 May;51(5):463-71. doi: 10.1016/j.phrs.2004.11.008.
Inflammation and leukocyte activation/infiltration play a major role in the initiation and progression of cardiovascular diseases including atherosclerosis and heart failure. Acute p38 mitogen-activated protein kinase (MAPK) pathway inhibition attenuates tissue damage and leukocyte accumulation in myocardial ischemia/reperfusion injury, although its effect on the acute phase of leukocyte recruitment has not been elucidated. The purpose of this study was to test the hypothesis that acute treatment of rats with a selective p38 inhibitor, SB-239063, inhibits ischemia/reperfusion-induced leukocyte-endothelial adhesion in vivo. Male Sprague-Dawley rats were treated with either SB-239063 (10 mgkg(-1)), dexamethasone (3 mgkg(-1)) or vehicle 1h prior to ischemia. Postcapillary venules were observed microscopically in exteriorized, superfused cremaster tissue. Leukocytes were fluorescently labeled in vivo using intravenous rhodamine 6G. Leukocyte adhesion, rolling, and rolling velocities were quantitated prior to 30 min ischemia, and at several time points during a 90 min reperfusion period. Ischemia caused a 3-fold increase in adherent leukocytes 5 min following reperfusion, a response that was maintained throughout the monitoring period (90 min) in vehicle-treated animals. SB-239063, at a dose known to inhibit p38 MAPK activity in vivo (10 mgkg(-1)), had no effect on ischemia/reperfusion-induced leukocyte adhesion, the number of rolling leukocytes, rolling velocities during the reperfusion period or adhesion molecule expression (P-, E-selectin, VCAM-1, ICAM-1). In contrast, dexamethasone completely blocked leukocyte adhesion in response to ischemia/reperfusion, and reduced expression of E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). We conclude that p38 MAPK may not play a role in initial leukocyte recruitment in response to ischemia/reperfusion injury, but could affect leukocyte emigration, thereby resulting in increased leukocyte accumulation in ischemic-reperfused tissue.
炎症和白细胞激活/浸润在包括动脉粥样硬化和心力衰竭在内的心血管疾病的发生和发展中起主要作用。急性p38丝裂原活化蛋白激酶（MAPK）通路抑制可减轻心肌缺血/再灌注损伤中的组织损伤和白细胞积聚，尽管其对白细胞募集急性期的影响尚未阐明。本研究的目的是检验以下假设：用选择性p38抑制剂SB - 239063对大鼠进行急性治疗可在体内抑制缺血/再灌注诱导的白细胞 - 内皮细胞黏附。雄性Sprague - Dawley大鼠在缺血前1小时接受SB - 239063（10 mgkg(-1)）、地塞米松（3 mgkg(-1)）或溶剂处理。在体外灌注的提睾肌组织中显微镜观察毛细血管后微静脉。使用静脉注射罗丹明6G在体内对白细胞进行荧光标记。在缺血30分钟前以及再灌注90分钟期间的几个时间点，对白细胞黏附、滚动和滚动速度进行定量。缺血导致再灌注后5分钟黏附白细胞增加3倍，在溶剂处理的动物中，这种反应在整个监测期（90分钟）内持续存在。已知在体内抑制p38 MAPK活性的剂量（10 mgkg(-1)）的SB - 239063对缺血/再灌注诱导的白细胞黏附、滚动白细胞数量、再灌注期间的滚动速度或黏附分子表达（P - 、E - 选择素、VCAM - 1、ICAM - 1）没有影响。相比之下，地塞米松完全阻断了缺血/再灌注引起的白细胞黏附，并降低了E - 选择素、细胞间黏附分子 - 1（ICAM - 1）和血管细胞黏附分子 - 1（VCAM - 1）的表达。我们得出结论，p38 MAPK可能在对缺血/再灌注损伤的初始白细胞募集中不起作用，但可能影响白细胞移出，从而导致缺血 - 再灌注组织中白细胞积聚增加。
