Scalia R, Lefer A M
Department of Physiology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-6799, USA.
J Leukoc Biol. 1998 Aug;64(2):163-9. doi: 10.1002/jlb.64.2.163.
The relationship between acute endothelial dysfunction and the extravasation of leukocytes was studied in vivo with intravital microscopy of the rat mesenteric microvasculature. Acute endothelial dysfunction of the rat mesenteric microvasculature was induced in vivo by superfusing the mesentery for 90 min with one of three different stimulating agents: NG-nitro-L-arginine methyl ester (L-NAME, 50 microM), thrombin (0.5 U/mL), or hydrogen peroxide (H2O2, 50 microM). All three agents induced a similar increase in leukocyte rolling and adherence, which was significantly greater than that observed in control rats superfused with Krebs-Henseleit solution (P < 0.01). Transendothelial migration of leukocytes into the perivascular space was also increased by superfusion with L-NAME, thrombin, or H2O2. However, there was a greater increase in the number of migrated leukocytes in the rat mesentery after L-NAME and H2O2 superfusion than that observed during thrombin superfusion. In vivo infusion of a neutralizing antibody against platelet-endothelial cell adhesion molecule-1 (PECAM-1) specifically inhibited L-NAME-induced and H2O2-induced migration of leukocytes but did not prevent extravasation of leukocytes induced by thrombin. In rat mesenteries superfused with the three different stimuli, immunohistochemical analysis of endothelial cell adhesion molecules expressed on the microvascular endothelium revealed a significant increase of ICAM-1, but not PECAM-1, endothelial cell surface expression (P < 0.01 and P > 0.05 vs. control rats, respectively). Our data confirm a key role for PECAM-1 acutely in leukocyte extravasation in vivo and indicate that the involvement of constitutively expressed PECAM-1 in leukocyte transendothelial migration is preferentially correlated to oxidative stress-related stimuli in the microvascular endothelium.
采用大鼠肠系膜微血管活体显微镜技术在体内研究急性内皮功能障碍与白细胞外渗之间的关系。通过用三种不同刺激剂之一对肠系膜进行90分钟的灌注，在体内诱导大鼠肠系膜微血管的急性内皮功能障碍：NG-硝基-L-精氨酸甲酯（L-NAME，50微摩尔）、凝血酶（0.5单位/毫升）或过氧化氢（H2O2，50微摩尔）。所有三种试剂均诱导白细胞滚动和黏附出现类似增加，且显著大于用Krebs-Henseleit溶液灌注的对照大鼠中观察到的增加（P<0.01）。用L-NAME、凝血酶或H2O2灌注也增加了白细胞跨内皮迁移到血管周围间隙。然而，与凝血酶灌注期间观察到的相比，L-NAME和H2O2灌注后大鼠肠系膜中迁移白细胞数量的增加更大。体内输注抗血小板内皮细胞黏附分子-1（PECAM-1）的中和抗体可特异性抑制L-NAME诱导和H2O2诱导的白细胞迁移，但不能阻止凝血酶诱导的白细胞外渗。在灌注三种不同刺激剂的大鼠肠系膜中，对微血管内皮上表达的内皮细胞黏附分子进行免疫组织化学分析显示，细胞间黏附分子-1（ICAM-1）的内皮细胞表面表达显著增加，但PECAM-1没有增加（分别与对照大鼠相比，P<0.01和P>0.05）。我们的数据证实了PECAM-1在体内白细胞外渗中起关键作用，并表明组成性表达的PECAM-1参与白细胞跨内皮迁移优先与微血管内皮中的氧化应激相关刺激有关。
