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Cellular and molecular mechanisms of Hydrogen Peroxide (H 2 O 2 )‐induced cell Injury and Barrier Dysfunction in Intact Venules
Author(s) -
Zhou Xueping,
He Pingnian
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.785.3
Subject(s) - chemistry , nitration , nitric oxide , reactive oxygen species , hydrogen peroxide , reactive nitrogen species , pathogenesis , microbiology and biotechnology , biophysics , biochemistry , medicine , biology , organic chemistry
Reactive oxygen species (ROS) has been implicated to play important roles in the pathogenesis of cardiovascular diseases, but the underlying mechanisms of ROS‐induced cell injury remain unclear. We previously showed that H 2 O 2 induced delayed but progressive increases in intra‐endothelial [Ca 2+ ] (EC [Ca 2+ ] i ), microvessel hydraulic conductivity (Lp), and cell apoptosis in intact venules. This study aims to investigate the roles of H 2 O 2 ‐induced nitric oxide (NO) production and subsequent formation of reactive nitrogen species in H 2 O 2 ‐induced Lp increases. NO and EC[Ca 2+ ] i were quantified in DAF‐2 and Fura‐2 loaded vessels and permeability was determined by measuring Lp in individually perfused rat mesenteric venules. Perfusing vessels with H 2 O 2 (10 μM) induced an immediate increase in NO and a plateau reached 9.1±0.4 times that of control at 45 min. The increased NO occurred prior to H 2 O 2 ‐induced increases in EC [Ca 2+ ] i and not affected by Ca 2+ influx inhibitor LaCl 3 . Confocal images revealed extensive tyrosine nitration in vessels exposed to H 2 O 2 for 2h but not in untreated vessels. Blocking H 2 O 2 ‐induced NO production with L‐NMMA not only abolished H 2 O 2 ‐induced increases in EC [Ca 2+ ] i and tyrosine nitration, but also prevented the Lp increases. Our results indicate that H 2 O 2 induced NOS activation in ECs via a Ca 2+ independent pathway and the excessive NO production and subsequent formation of reactive nitrogen species‐mediated cell injury is the key for H 2 O 2 ‐induced microvascular barrier dysfunction. Supported by HL56237 and HL084338.