College of Nursing, University of Arizona, Tucson, AZ, USA.
Biol Res Nurs. 2011 Apr;13(2):154-63. doi: 10.1177/1099800410384500. Epub 2010 Nov 1.
As a natural response to injury and disease, neutrophils activate, adhere to the microvasculature, migrate into brain tissue, and release toxic substances such as reactive oxygen species and proteases. This neutrophil response occurs when blood flow is returned to brain tissue (reperfusion) after ischemic stroke. Thus, the presence of activated systemic neutrophils increases the potential for tissue injury during reperfusion after ischemic stroke. Although experiments in rat models suggest that activated neutrophils play a pivotal role in cerebral ischemia reperfusion injury, little is known about systemic neutrophil activation during reperfusion following ischemic stroke in a mouse model. The purpose of this study was to characterize systemic leukocyte responses and neutrophil CD11b expression 15-min and 24-hr post-reperfusion in a mouse model of ischemic stroke. The intraluminal filament method of transient middle cerebral artery occlusion (tMCAO) with reperfusion or a sham procedure was performed in male C57Bl/6 mice. Automated leukocyte counts and manual white blood cell (WBC) differential counts were measured. Flow cytometry was used to assess systemic neutrophil surface CD11b expression. The data suggest that the damaging potential of systemic neutrophil activation begins as early as 15 min and remains evident at 24 hr after the initiation of reperfusion. In addition, because transgenic mouse models, bred on a C57Bl/6 background, are increasingly used to elucidate single mechanisms of reperfusion injury after ischemic stroke, findings from this study are foundational for future investigations examining the damaging potential of neutrophil responses post-reperfusion after ischemic stroke in genetically altered mouse models within this background strain.
作为对损伤和疾病的自然反应，中性粒细胞会被激活，黏附于微血管，迁移到脑组织，并释放活性氧物质和蛋白酶等毒性物质。这种中性粒细胞反应发生在缺血性中风后血流重新回到脑组织（再灌注）时。因此，在缺血性中风后再灌注期间，激活的系统性中性粒细胞的存在增加了组织损伤的可能性。尽管大鼠模型中的实验表明激活的中性粒细胞在脑缺血再灌注损伤中发挥关键作用，但对于缺血性中风后小鼠模型中再灌注期间系统性中性粒细胞的激活知之甚少。本研究的目的是描述缺血性中风小鼠模型中再灌注后 15 分钟和 24 小时的系统性白细胞反应和中性粒细胞 CD11b 表达。采用可复通的管内线栓法制作短暂性大脑中动脉闭塞（tMCAO）伴再灌注或假手术，自动进行白细胞计数和手动白细胞（WBC）分类计数，流式细胞术评估系统性中性粒细胞表面 CD11b 表达。数据表明，系统性中性粒细胞激活的损伤潜力早在再灌注后 15 分钟就开始显现，并在再灌注后 24 小时仍然明显。此外，由于基于 C57Bl/6 背景的转基因小鼠模型越来越多地被用于阐明缺血性中风后再灌注损伤的单一机制，因此本研究的发现为未来在该背景品系的遗传改变小鼠模型中研究缺血性中风后再灌注中性粒细胞反应的损伤潜力奠定了基础。
