Lung eNOS and iNOS are reoxygenation time-dependent upregulated after acute hypoxia.
Nitric oxide plays a critical role in many physiological and physiopathological processes in the lung. Changes in the NO/NOS (Nitric Oxide/Nitric Oxide Synthase) system after hypoxia situations remain controversial in this organ, so that the aim of this work is to perform a complete study of this system in the hypoxic lung after different reoxygenation times ranging from 0 h to 5 days posthypoxia. This is a novel follow-up study carried out in Wistar rats submitted for 30 min to acute hypobaric hypoxia. We measured endothelial and inducible NOS (eNOS, iNOS) mRNA and protein expression, location, and in situ NOS activity as well as nitrated protein expression and location. In addition, NO levels were indirectly quantified (NOx) as well as the apoptosis level. Results showed an increase in eNOS mRNA, protein, activity as well as eNOS positive immunostaining at 0 h posthypoxia, coinciding with raised NOx levels. Contrary, iNOS, nitrated protein expression and apoptosis level augmented during the final reoxygenation times. The lung NO/NOS system provokes two responses to the hypoxia/reoxygenation processes: (i) eNOS is responsible of the immediate response, producing NO, which causes vasodilation and bronchodilation, and (ii) iNOS is related to the second late response, which seems to be involved in some of the deleterious consequences that hypoxia induces in the lung.
Department of Experimental Biology, University of Jaén, Jaén, Spain.
Alma
A
Rus
María Angeles
MA
Peinado
Lourdes
L
Castro
María Luisa
ML
Del Moral
D000208:Acute Disease; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D004195:Disease Models, Animal; D000860:Hypoxia / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D007150:Immunohistochemistry; D008168:Lung / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology*
D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat