Zhou Xueping, Wen Ke, Yuan Dong, Ai Ling, He Pingnian
Dept. of Physiology and Pharmacology, School of Medicine, West Virginia Univ., Morgantown, WV 26506-9229, USA.
Am J Physiol Heart Circ Physiol. 2009 Apr;296(4):H1096-107. doi: 10.1152/ajpheart.01037.2008. Epub 2009 Feb 6.
Our previous study demonstrated that reactive oxygen species (ROS) released from activated blood cells contribute significantly to the increased microvessel permeability during inflammation. This study aims to define the individual roles of hydrogen peroxide (H(2)O(2)) and superoxide in ROS-induced increases in permeability and endothelial intracellular Ca(2+) concentration (Ca(2+)) in individually perfused rat mesenteric venules. Microvessel permeability was determined by measuring hydraulic conductivity (L(p)). Endothelial Ca(2+) was measured in fura-2 AM-loaded microvessels. Perfusing microvessels with superoxide generated by hypoxanthine and xanthine oxidase (HX/XO) induced immediate and transient increases in L(p). The mean peak value, which occurred within 5 min of HX/XO exposure, was 4.3 +/- 0.6 times that of the control. In contrast, the perfusion of H(2)O(2) (100 and 500 microM) caused no immediate increases in L(p). A significant L(p) increase, 3.6 +/- 0.6 times the control value, occurred 30 min after the perfusion of H(2)O(2) at 500 microM. The perfusion of H(2)O(2) at 100 or 500 microM for 1 h increased L(p) to 6.6 +/- 0.9 and 11.3 +/- 3.6 times the control value, respectively. The increased endothelial Ca(2+) in HX/XO or H(2)O(2) perfused vessels was correlated with the time course of the increases in L(p). Inhibiting Ca(2+) influx by LaCl(3) prevented the permeability increase induced by HX/XO or H(2)O(2). These results demonstrated differential actions of superoxide and H(2)O(2) on microvessel permeability and endothelial Ca(2+). Superoxide-induced permeability increases were immediate and transient, whereas H(2)O(2)-induced permeability increases were progressive, demonstrating concentration and time dependence. Ca(2+) influx plays an essential role in both superoxide and H(2)O(2)-induced permeability increases.
我们之前的研究表明，活化血细胞释放的活性氧（ROS）在炎症过程中对微血管通透性增加有显著贡献。本研究旨在确定过氧化氢（H₂O₂）和超氧化物在ROS诱导的单独灌注大鼠肠系膜小静脉通透性增加以及内皮细胞内钙离子浓度（[Ca²⁺]i）升高中的各自作用。微血管通透性通过测量水力传导率（Lp）来确定。内皮细胞[Ca²⁺]i在负载fura-2 AM的微血管中进行测量。用次黄嘌呤和黄嘌呤氧化酶（HX/XO）产生的超氧化物灌注微血管会立即引起Lp的短暂升高。HX/XO暴露后5分钟内出现的平均峰值是对照组的4.3±0.6倍。相比之下，灌注H₂O₂（100和500微摩尔）不会立即引起Lp升高。在灌注500微摩尔H₂O₂ 30分钟后，Lp显著升高，为对照值的3.6±0.6倍。灌注100或500微摩尔H₂O₂ 1小时分别使Lp升高至对照值的6.6±0.9倍和11.3±3.6倍。HX/XO或H₂O₂灌注血管中内皮细胞[Ca²⁺]i的升高与Lp升高的时间进程相关。用LaCl₃抑制Ca²⁺内流可防止HX/XO或H₂O₂诱导的通透性增加。这些结果表明超氧化物和H₂O₂对微血管通透性和内皮细胞[Ca²⁺]i有不同作用。超氧化物诱导的通透性增加是立即且短暂的，而H₂O₂诱导的通透性增加是渐进的，表现出浓度和时间依赖性。Ca²⁺内流在超氧化物和H₂O₂诱导的通透性增加中都起重要作用。
