Y Minamiya, S Abo, M Kitamura, K Izumi, Y Kimura, K Tozawa and S Saito
Second Department of Surgery, Akita University, School of Medicine, Japan.

Although the importance of free oxygen radical has been reported in acute lung injury, the direct evidence in vivo model was lacking. We report a new method, which for the first time allows direct detection of hydrogen peroxide in the intact rat pulmonary microcirculation. We used the computer image-analyzing system and 2',7'-dichlorofluorescin diacetate for the marker of hydrogen peroxide production in vivo. A rat sepsis model was produced by continuous infusion of endotoxin for 30, 60, and 120 min. Hydrogen peroxide production in the pulmonary microcirculation of the sepsis rat was higher than in the control rat at each time point (p < 0.01) and increased time-dependently (p < 0.01). Catalase (5,000 U/kg) almost completely inhibited the hydrogen peroxide production in the sepsis rat (p < 0.01). In high-power view, hydrogen peroxide was detected in granulocytes that adhered to the capillaries and endothelial cells that were adjoining adherent granulocytes. These observations suggest that hydrogen peroxide in the endothelium was diffused from granulocytes. In this study, we demonstrated direct evidence of hydrogen peroxide production from adherent granulocytes in intact rat lung treated with endotoxin. We conclude that endotoxin causes the granulocyte adhesion and oxidative stress to the endothelium due to adherent granulocytes within 30 min in the pulmonary microcirculation.

This article has been cited by other articles:

				S. S. Iyer, D. P. Jones, K. L. Brigham, and M. Rojas Oxidation of Plasma Cysteine/Cystine Redox State in Endotoxin-Induced Lung Injury Am. J. Respir. Cell Mol. Biol., January 1, 2009; 40(1): 90 - 98. [Abstract] [Full Text] [PDF]

				T. Ruan, Y. S. Lin, K.-S. Lin, and Y. R. Kou Mediator mechanisms involved in TRPV1 and P2X receptor-mediated, ROS-evoked bradypneic reflex in anesthetized rats J Appl Physiol, August 1, 2006; 101(2): 644 - 654. [Abstract] [Full Text] [PDF]

				T. Ruan, Y. S. Lin, K.-S. Lin, and Y. R. Kou Sensory transduction of pulmonary reactive oxygen species by capsaicin-sensitive vagal lung afferent fibres in rats J. Physiol., June 1, 2005; 565(2): 563 - 578. [Abstract] [Full Text] [PDF]

				C. J. Lai, T. Ruan, and Y. R. Kou The involvement of hydroxyl radical and cyclooxygenase metabolites in the activation of lung vagal sensory receptors by circulatory endotoxin in rats J Appl Physiol, February 1, 2005; 98(2): 620 - 628. [Abstract] [Full Text] [PDF]

				T. Ruan, C.-Y. Ho, and Y. R. Kou Afferent vagal pathways mediating respiratory reflexes evoked by ROS in the lungs of anesthetized rats J Appl Physiol, May 1, 2003; 94(5): 1987 - 1998. [Abstract] [Full Text] [PDF]

				N. J. Pelaez, T. R. Braun, R. J. Paul, R. A. Meiss, and C. S. Packer H2O2 mediates Ca2+- and MLC20 phosphorylation-independent contraction in intact and permeabilized vascular muscle Am J Physiol Heart Circ Physiol, September 1, 2000; 279(3): H1185 - H1193. [Abstract] [Full Text] [PDF]

				Y. MINAMIYA, S. MOTOYAMA, M. KITAMURA, S. SAITO, K. TERADA, and J.-I. OGAWA The Requirement of Intercellular Adhesion Molecule-1 for Neutrophil Respiratory Burst in the Pulmonary Circulation of Rats Infused with Endotoxin Am. J. Respir. Crit. Care Med., August 1, 1998; 158(2): 635 - 642. [Abstract] [Full Text] [PDF]

				Y. Minamiya, K. Tozawa, M. Kitamura, S. Saito, and J.-i. Ogawa Platelet-activating Factor Mediates Intercellular Adhesion Molecule-1-dependent Radical Production in the Nonhypoxic Ischemia Rat Lung Am. J. Respir. Cell Mol. Biol., July 1, 1998; 19(1): 150 - 157. [Abstract] [Full Text]