Reactive oxygen species from NADPH oxidase contribute to altered pulmonary vascular responses in piglets with chronic hypoxia-induced pulmonary hypertension

• Published in: American journal of physiology. Lung cellular and molecular physiology Vol. 295; no. 5; pp. L881 - L888
• Main Authors: Fike, Candice D, Slaughter, James C, Kaplowitz, Mark R, Zhang, Yongmei, Aschner, Judy L
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.11.2008
• Subjects: Acetylcholine - pharmacology; Animals; Cells; Chronic Disease; Enzymes; Hogs; Hypertension, Pulmonary - enzymology; Hypoxia; Hypoxia - complications; Immunoblotting; Ions; Luminescence; NADP - pharmacology; NADPH Oxidases - metabolism; Pulmonary Artery - drug effects; Pulmonary Circulation - drug effects; Reactive Oxygen Species - metabolism; Swine; Vascular Resistance - drug effects; Veins & arteries
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00047.2008

Departments of 1 Pediatrics and 2 Biostatistics, 3 The Vanderbilt Kennedy Center, and the 4 Center for Molecular Toxicology, Vanderbilt University Medical Center, Nashville, Tennessee Submitted 24 January 2008 ; accepted in final form 25 August 2008 Our main objective was to determine whether reactive oxygen species (ROS), such as superoxide (O 2 – ) and hydrogen peroxide (H 2 O 2 ), contribute to altered pulmonary vascular responses in piglets with chronic hypoxia-induced pulmonary hypertension. Piglets were raised in either room air (control) or hypoxia for 3 days. The effect of the cell-permeable superoxide dismutase mimetic (SOD; M40403 ) and/or PEG-catalase (PEG-CAT) on responses to acetylcholine (ACh) was measured in endothelium-intact and denuded pulmonary resistance arteries (PRAs; 90-to-300-µm diameter). To determine whether NADPH oxidase is an enzymatic source of ROS, PRA responses to ACh were measured in the presence and absence of a NADPH oxidase inhibitor, apocynin (APO). A Western blot technique was used to assess expression of the NADPH oxidase subunit, p67phox. A lucigenin-derived chemiluminescence technique was used to measure ROS production stimulated by the NADPH oxidase substrate, NADPH. ACh responses, which were dilation in intact control arteries but constriction in both intact and denuded hypoxic arteries, were diminished by M40403 , PEG-CAT, the combination of M40403 plus PEG-CAT, as well as by APO. Although total amounts were not different, membrane-associated p67phox was greater in PRAs from hypoxic compared with control piglets. NADPH-stimulated lucigenin luminescence was nearly doubled in PRAs from hypoxic vs. control piglets. We conclude that ROS generated by NADPH oxidase contribute to the aberrant pulmonary arterial responses in piglets exposed to 3 days of hypoxia. superoxide; superoxide dismutase; p67phox; hydrogen peroxide; M40403; M40401 Address for reprint requests and other correspondence: C. D. Fike, Dept. of Pediatrics, Vanderbilt Univ. Medical Center, 2215 B Garland Ave., 1125 MRB IV/Light Hall, Nashville, TN 37232-0656 (e-mail: candice.fike{at}vanderbilt.edu )