Kubes P, Suzuki M, Granger D N
Department of Physiology, Louisiana State University Medical Center, Shreveport 71130.
Proc Natl Acad Sci U S A. 1991 Jun 1;88(11):4651-5. doi: 10.1073/pnas.88.11.4651.
The objective of this study was to determine whether endogenous nitric oxide (NO) inhibits leukocyte adhesion to vascular endothelium. This was accomplished by superfusing a cat mesenteric preparation with inhibitors of NO production, NG-monomethyl-L-arginine (L-NMMA) or NG-nitro-L-arginine methyl ester (L-NAME), and observing single (30-microns diameter) venules by intravital video microscopy. Thirty minutes into the superfusion period the number of adherent and emigrated leukocytes, the erythrocyte velocity, and the venular diameter were measured; venular blood flow and shear rate were calculated from the measured parameters. The contribution of the leukocyte adhesion glycoprotein CD11/CD18 was determined using the CD18-specific monoclonal antibody IB4. Both inhibitors of NO production increased leukocyte adherence more than 15-fold. Leukocyte emigration was also enhanced, whereas venular shear rate was reduced by nearly half. Antibody IB4 abolished the leukocyte adhesion induced by L-NMMA and L-NAME. Incubation of isolated cat neutrophils with L-NMMA, but not L-NAME, resulted in direct upregulation of CD11/CD18 as assessed by flow cytometry. Decrements in venular shear rate induced by partial occlusion of the superior mesenteric artery in untreated animals revealed that only a minor component of L-NAME-induced leukocyte adhesion was shear rate-dependent. The L-NAME-induced adhesion was inhibited by L-arginine but not D-arginine. These data suggest that endothelium-derived NO may be an important endogenous modulator of leukocyte adherence and that impairment of NO production results in a pattern of leukocyte adhesion and emigration that is characteristic of acute inflammation.
本研究的目的是确定内源性一氧化氮（NO）是否抑制白细胞与血管内皮的黏附。通过用NO生成抑制剂NG-单甲基-L-精氨酸（L-NMMA）或NG-硝基-L-精氨酸甲酯（L-NAME）灌注猫肠系膜标本，并通过活体视频显微镜观察单个（直径30微米）小静脉来实现这一目的。在灌注期30分钟时，测量黏附和游出的白细胞数量、红细胞速度和小静脉直径；根据测量参数计算小静脉血流和剪切率。使用CD18特异性单克隆抗体IB4确定白细胞黏附糖蛋白CD11/CD18的作用。两种NO生成抑制剂均使白细胞黏附增加超过15倍。白细胞游出也增强，而小静脉剪切率降低近一半。抗体IB4消除了L-NMMA和L-NAME诱导的白细胞黏附。用L-NMMA而非L-NAME孵育分离的猫中性粒细胞，通过流式细胞术评估发现CD11/CD18直接上调。在未处理的动物中，肠系膜上动脉部分闭塞诱导的小静脉剪切率降低表明，L-NAME诱导的白细胞黏附中只有一小部分依赖于剪切率。L-NAME诱导的黏附被L-精氨酸抑制，但不被D-精氨酸抑制。这些数据表明，内皮源性NO可能是白细胞黏附的重要内源性调节因子，NO生成受损会导致白细胞黏附和游出模式，这是急性炎症的特征。
