LEUKOCYTE KINETICS IN THE MICROCIRCULATION

白细胞在微血管内皮上的粘附和迁移 是炎症反应的标志， 特别是在败血症、休克和 缺血/再灌注 我们已经能够证明在以前的 研究表明，白细胞截留在微循环的形式， 毛细血管堵塞和毛细血管后附着于内皮 构成了破坏组织稳态的关键方面。 我们的过去 研究，主要集中在血管内事件，将 扩展到探索不同白细胞在组织分解中的作用 在细胞迁移穿过微血管壁期间， 在阿米巴样的迁移过程中 我们建议的研究 旨在提供白细胞计数期间关键事件的详细信息， 介导的组织损伤，利用新开发的数字荧光 活体显微镜方法在大鼠的选定组织中。 我们 一种假说提出，激活的白细胞在组织中迁移， 活化的内皮细胞作为自由基介导的 刺激后组织损伤。 过氧化物荧光标记物 形成，线粒体功能和细胞死亡将被用于 与延时显微摄影相结合来记录连续的细节 与组织中白细胞迁移相关的事件。 的 涉及的膜粘附机制（整合素和选择素） 在间隙迁移将进行研究，在存在选定的 刺激物。 负责生产无氧的机制 自由基及其对实质细胞死亡的后果将是 在高光学分辨率下首次在体内定量， 鉴定 在中性粒细胞与血管内的相互作用过程中， 内皮细胞，铁催化羟自由基过氧化 形成发生在两者之间的紧密接触区域 细胞膜 这一机制将在体内进行探索， 白细胞迁移到淋巴结的条件， 对不同促炎刺激物的反应。 一个人经常观察 在白细胞穿过微血管壁的迁移过程中， 微出血性红细胞素质的形成 间质红细胞池。 这一现象在 许多临床情况，但其潜在的细胞和分子 机制尚未探索。 我们的假设是， 移植需要白细胞的初始粘附和渗出， 红细胞逃逸到氚中与铁有关 催化羟基自由基的形成， 过氧化和细胞死亡。 白细胞在体内的作用机制 血液渗出形成足够大的孔，使红细胞逃逸， 使用活体和电子显微镜结合 建模 过氧化物的产生，细胞的死亡， 存在微血管和结缔组织变性 细胞将利用数字荧光显微镜进行研究， vivo. 一个系统的程序沿着这些路线将有助于确定关键 在激活的细胞因子存在下导致组织损伤的机制 白细胞和内皮细胞。

The attachment of leukocytes to microvascular endothelium and migration into the interstitium is the hallmark of the inflammatory reaction that is especially deleterious in sepsis, shock, and episodes of ischemia/reperfusion. We have been able to demonstrate in previous studies that leukocyte entrapment in the microcirculation in the form of capillary plugging and post-capillary attachment to the endothelium constitutes a key facet of the disruption of tissue homeostasis. Our past studies, which were focused largely on intravascular events, will be expanded to explore the role of different leukocytes in tissue breakdown during the period of cell migration across the wall of microvessels and during amoeboid migration within the interstitium. Our proposed studies are designed to provide details of the key events during leukocyte mediated tissue injury, utilizing a newly developed digital fluorescent intravital microscopy approach in selected tissues of the rat. Our hypothesis proposes that activated leukocytes migrating in the tissue and activated endothelial cells serve as sources for free radical mediated tissue injury after stimulation. Fluorescent markers for peroxide formation, mitochondrial function and cell death will be utilized in conjunction with time-lapse microphotography to record sequential details of the events associated with leukocyte migration in the tissue. The membrane adhesion mechanisms (integrins and selectins) that are involved in interstitial migration will be investigated in the presence of selected stimulators. The mechanisms responsible for the production of oxygen free radicals and their consequences for parenchymal cell death will be quantified the first time in vivo at high optical resolution and identified. During the intravascular interaction between neutrophils and endothelial cells, peroxidation by iron catalyzed hydroxyl radical formation takes place in the region of close contact between the two cellular membranes. This mechanism will be explored in vivo under conditions where leukocytes are migrating into the interstitium in response to different proinflammatory stimulators. One observes regularly during migration of leukocytes across the microvascular wall, the development of micro-hemorrhagic erythrocyte diathesis and formation of interstitial pools of red cells. This phenomenon has been observed in many clinical situations but its underlying cellular and molecular mechanisms are unexplored. It is our hypothesis that formation of micro- hemorrhages requires an initial adhesion and diapedesis of leukocytes, and that red cell escape into the interstitium is associated with iron catalyzed hydroxyl radical formation and in turn enhanced parenchymal peroxidation and cell death. The mechanisms by which leukocytes in diapedesis form pores large enough for red cell escape will be investigated using intravital and electron microscopy in combination with modeling. The production of peroxides, cell death in the interstitium in the presence of micro-hemorrhages, and degeneration of connective tissue cells will be investigated utilizing digital fluorescent microscopy in vivo. A systematic program along these lines will serve to identify key mechanisms that lead to tissue damage in the presence of activated leukocytes and endothelial cells.