The mechanical property of neutrophils to inflammatory process and sequestration into the lung.

由于肺毛细血管的球形直径小于中性粒细胞的球形直径，因此增加的中性粒细胞硬度或相反地减少的中性粒细胞变形性是炎症过程期间中性粒细胞在肺内的初始隔离的关键步骤。抗凝血酶III（AT）对弥散性血管内凝血具有治疗作用，越来越多的证据表明AT还具有抗炎作用。其抗炎作用的机制尚不清楚，但在大鼠内毒素模型中，AT明显抑制肺中的中性粒细胞隔离。因此，在本体外研究中，我们研究了AT对人中性粒细胞变形能力的影响，并将这些结果与其F-肌动蛋白含量相关。在存在或不存在AT的α、β或低肝素亲和力亚型（1 IU/ml，20 min）的情况下，用fMLP（1 μM，2 min）刺激分离的人中性粒细胞，并使用过滤器测定系统评价变形性。中性粒细胞也用FITC-鬼笔环肽染色，并进行FACS扫描以评估F-肌动蛋白含量。结果表明，任何三种AT亚型的预处理类似地抑制了中性粒细胞变形能力的降低和F-肌动蛋白含量的增加。值得注意的是，在存在或不存在AT的情况下，肝素酶对变形性或F-肌动蛋白含量没有影响，这有点出乎意料，因为硫酸肝素蛋白聚糖可能起AT受体的作用。这些结果表明，AT抑制中性粒细胞刚度增加炎症过程中看到的抑制肌动蛋白聚合通过肝素非依赖性途径。

Because the spherical diameter of pulmonary capillaries is smaller than that of neutrophils, increased neutrophil stiffness or, conversely, decreased neutrophil deformability is a key step in the initial sequestration of neutrophils within the lungs during inflammatory processes. Antithrombin III (AT) is known exert a therapeutic effect against disseminated intravascular coagulation, and accumulating evidence suggests that AT also has anti-inflammatory properties. The mechanisms of its anti-inflammatory effects remain unclear, but in a rat endotoxin model AT apparently inhibited neutrophil sequestration in the lung. In the present in vitro study, therefore, we examined the effect of AT on the deformability of human neutrophils and correlated those findings with their F-actin content. Isolated human neutrophils were stimulated with fMLP (1 μM, 2 min) in the presence or absence of the α, β or low-heparin-affinity isoforms of AT (1 IU/ml, 20 min), and deformability was evaluated using a filter assay system. Neutrophils were also stained with FITC-phalloidin and subjected to FACS-scan to assess F-actin content. The results showed that pretreatment with any of the three AT isoforms similarly inhibited the decreased neutrophil deformability and increased F-actin content. Notably, heparinase had no effect on either deformability or F-actin content in the presence or absence of AT, which was somewhat unexpected, as heparin sulfate proteoglycans likely function as AT receptors. These findings suggested that AT inhibits the increase in neutrophil stiffness seen during inflammatory processes by inhibiting actin polymerization via a heparin-independent pathway.