{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,17]],"date-time":"2026-04-17T13:46:17Z","timestamp":1776433577841,"version":"3.51.2"},"reference-count":18,"publisher":"Public Library of Science (PLoS)","issue":"1","license":[{"start":{"date-parts":[[2024,1,22]],"date-time":"2024-01-22T00:00:00Z","timestamp":1705881600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000006","name":"Office of Naval Research","doi-asserted-by":"publisher","award":["N00014-20-1-2763"],"award-info":[{"award-number":["N00014-20-1-2763"]}],"id":[{"id":"10.13039\/100000006","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:sec id=\"sec001\">\n<jats:title>Background<\/jats:title>\n<jats:p>Breathing pure oxygen causes nitrogen washout from tissues, a method commonly deployed to prevent decompression sickness from hypobaric exposure. Theoretically prebreathing oxygen increases the capacity for nitrogen uptake and potentially limits supersaturation during dives of short duration. We aimed to use <jats:sup>13<\/jats:sup>N<jats:sub>2<\/jats:sub>, a radioactive nitrogen isotope, to quantify tissue nitrogen following normobaric and hyperbaric exposures.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec002\">\n<jats:title>Methods<\/jats:title>\n<jats:p>Twenty Sprague Dawley rats were divided in 4 conditions; normobaric prebreathe, normobaric control, hyperbaric prebreathe, hyperbaric control. Prebreathed rats breathed oxygen for 1 h prior to the experiment whilst controls breathed air. Normobaric rats breathed air containing <jats:sup>13<\/jats:sup>N<jats:sub>2<\/jats:sub> at 100 kPa for 30 min, whereas hyperbaric rats breathed <jats:sup>13<\/jats:sup>N<jats:sub>2<\/jats:sub> at 700 kPa before being decompressed and sedated using air-isoflurane (without <jats:sup>13<\/jats:sup>N<jats:sub>2<\/jats:sub> for a few minutes). After euthanization, blood, brain, liver, femur and thigh muscle were analyzed by gamma counting.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec003\">\n<jats:title>Results<\/jats:title>\n<jats:p>At normobaria prebreathing oxygen resulted in higher absolute nitrogen counts in blood (p = .034), as well as higher normalized counts in both the liver and muscle (p = .034). However, following hyperbaric exposure no differences were observed between conditions for any organ (p&gt;.344). Both bone and muscle showed higher normalized counts after hyperbaria compared to normobaria.<\/jats:p>\n<\/jats:sec>\n<jats:sec id=\"sec004\">\n<jats:title>Conclusions<\/jats:title>\n<jats:p>Oxygen prebreathing caused nitrogen elimination in normobaria that led to a larger \u201csink\u201d and uptake of <jats:sup>13<\/jats:sup>N<jats:sub>2<\/jats:sub>. The lack of difference between conditions in hyperbaria could be due to the duration and depth of the dive mitigating the effect of prebreathing. In the hyperbaric conditions the lower counts were likely due to off-gassing of nitrogen during the sedation procedure, suggest a few minutes was enough to off-gas in rodents. The higher normalized counts under hyperbaria in bone and muscle likely relate to these tissues being slower to on and off-gas nitrogen. Future experiments could include shorter dives and euthanization while breathing <jats:sup>13<\/jats:sup>N<jats:sub>2<\/jats:sub> to prevent off-gassing.<\/jats:p>\n<\/jats:sec>","DOI":"10.1371\/journal.pone.0294611","type":"journal-article","created":{"date-parts":[[2024,1,22]],"date-time":"2024-01-22T18:24:43Z","timestamp":1705947883000},"page":"e0294611","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":3,"title":["Effects of oxygen-prebreathing on tissue nitrogenation in normobaric and hyperbaric conditions"],"prefix":"10.1371","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9147-6116","authenticated-orcid":true,"given":"Edward Tom","family":"Ashworth","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ryotaro","family":"Ogawa","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"David Robert","family":"Vera","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Peter","family":"Lindholm","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"340","published-online":{"date-parts":[[2024,1,22]]},"reference":[{"issue":"13","key":"pone.0294611.ref001","doi-asserted-by":"crossref","first-page":"1254","DOI":"10.1056\/NEJMra2116554","article-title":"Decompression Sickness and Arterial Gas Embolism","volume":"386","author":"SJ Mitchell","year":"2022","journal-title":"N Engl J Med"},{"issue":"3","key":"pone.0294611.ref002","first-page":"537","article-title":"The lung as a filter for microbubbles","volume":"47","author":"BD Butler","year":"1979","journal-title":"J Appl Physiol Respir Environ Exerc Physiol"},{"key":"pone.0294611.ref003","doi-asserted-by":"crossref","first-page":"s16","DOI":"10.1016\/S0140-6736(03)15059-3","article-title":"Physiological hazards of flight at high altitude","volume":"362","author":"AA Pilmanis","year":"2003","journal-title":"The Lancet"},{"key":"pone.0294611.ref004","unstructured":"Conkin J. 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