Inflammatory cell infiltration after endothelin-1-induced cerebral ischemia: histochemical and myeloperoxidase correlation with temporal changes in brain injury
Inflammatory cell infiltration after endothelin-1-induced cerebral ischemia: histochemical and myeloperoxidase correlation with temporal changes in brain injury
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DOI：
10.1038/sj.jcbfm.9600324
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发表时间：
2007-01-01
影响因子：
6.3
通讯作者：
Callaway, Jennifer K.
中科院分区：
文献类型：
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作者：
Weston, Robert M.;Jones, Nicole M.;Callaway, Jennifer K.
短暂局灶性脑卒中后中性粒细胞在脑内的积累仍然存在争议，一些研究表明中性粒细胞是有害的，而另一些研究表明中性粒细胞不会导致缺血性损伤。髓过氧化物酶（MPO）已被广泛用作量化中性粒细胞积累的标记物，但它是一种间接方法，不能单独检测中性粒细胞。为了阐明巨噬细胞在中性粒细胞炎症反应中的相互作用，我们在缺血后0、1、2、3、7和15天对脑切片进行了双标记免疫荧光检测。这些结果均来自同一动物，以确定中性粒细胞浸润与缺血性损伤之间的相关性。发现脑缺血后3天MPO活性升高。双染色显示巨噬细胞吞噬脑内的中性粒细胞，并且随着时间的增加，吞噬中性粒细胞的数量增加，第3天吞噬脑内中性粒细胞的比例为50%，第15天约为85% （N= 5, P < 0.05）。有趣的是，在第7天，双染色量减少到20% （N= 5, P < 0.05）。中性粒细胞浸润与皮层和纹状体缺血损伤呈显著正相关（r(2)分别= 0.86和0.80,P < 0.01）。本研究的结果表明，被巨噬细胞吞噬的中性粒细胞的MPO可能继续促进整体MPO活性，并且先前使用该标记物来测量中性粒细胞积累的评估可能错误地计算了缺血区域内中性粒细胞的数量，从而导致它们在稍后时间点对梗死演变的贡献。因此，任何嗜中性粒细胞的双期浸润都可能被巨噬细胞的积聚所掩盖。
Accumulation of neutrophils in brain after transient focal stroke remains controversial with some studies showing neutrophils to be deleterious, whereas others suggest neutrophils do not contribute to ischemic injury. Myeloperoxidase (MPO) has been used extensively as a marker for quantifying neutrophil accumulation, but is an indirect method and does not detect neutrophils alone. To elucidate the interaction of macrophages in the neutrophil inflammatory response, we conducted double- label immunofluorescence in brain sections at 0, 1, 2, 3, 7, and 15 days after ischemia. Each of these results was obtained from the same animal to determine correlations between neutrophil infiltration and ischemic damage. It was found that MPO activity increased up to 3 days after cerebral ischemia. Dual-staining revealed that macrophages engulf neutrophils in the brain and that this engulfment of neutrophils increased with time, with 50% of neutrophils in the brain engulfed at 3 days and approximately 85% at 15 days (N= 5, P < 0.05). Interestingly, at 7 days the amount of dual-staining was decreased to 20% (N= 5, P < 0.05). Neutrophil infiltration was positively correlated with ischemic damage in both the cortex and striatum (r(2) = 0.86 and 0.80, respectively, P < 0.01). The results of this study indicate that the MPO from neutrophils phagocytized by macrophages may continue to contribute to the overall MPO activity, and that previous assessments that have utilized this marker to measure neutrophil accumulation may have miscalculated the number of neutrophils within the ischemic territory and hence their contribution to the evolution of the infarct at later time points. Thus any biphasic infiltration of neutrophils may have been masked by the accumulation of macrophages.