{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T05:03:31Z","timestamp":1790053411462,"version":"4.0.1"},"reference-count":51,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T00:00:00Z","timestamp":1790035200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>The study investigated the effec of dexamethasone (Dex) treatment, acute prolonged swimming, and their combination on skeletal muscle mass, oxidative stress, iron metabolism, and AKT-mediated signaling in two muscle types.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Rats were divided into four groups (n=8 per group): intraperitoneal saline or Dex (1mg\/kg\/day) treatment for 9 days (non-exercised and exercised). Animals in exercise groups underwent a 4-day preparatory swimming procedure followed by a single 3h swimming session. The soleus (SOL) and extensor digitorum longus (EDL) muscles were collected, weighed, and used for analysis. We assessed lipid and protein peroxidation markers, catalase activity, iron-metabolism proteins, and AKT-dependent proteolysis and synthesis pathways.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Nine days of Dex treatment significantly reduced SOL (-12%, p&amp;lt;0.01) and EDL (-15%, p&amp;lt;0.001) mass, accompanied by oxidative stress (increased protein peroxidation, p&amp;lt;0.001) and alterations in iron metabolism: increased FH (SOL: +88%, p&amp;lt;0.01, EDL: +80%, p&amp;lt;0.01) and decreased PCBP1 (SOL: -59%, p&amp;lt;0.001, EDL: -33%, p&amp;lt;0.05). Dex treatment also affected proteins involved in synthesis and proteolysis pathways: in SOL, lowered total AKT (-22%, p&amp;lt;0.05) and pmTOR (-24%, p&amp;lt;0.05); in EDL, decreased MuRF-1 (-30%, p&amp;lt;0.01) and total mTOR (-24%, p&amp;lt;0.01), highlighting mechanisms underlying muscle loss. In saline-treated rats, acute prolonged swimming, following 4 days of preparatory exercise, did not affect SOL and EDL mass or oxidative stress markers. However, in SOL, swimming reduced PCBP1 (-43%, p&amp;lt;0.001), decreased total AKT (-33%, p&amp;lt;0.01) and pAKT (-47%, p&amp;lt;0.01), increased Atrogin-1 levels (+38%, p&amp;lt;0.001), and decreased pmTOR (-52%, p&amp;lt;0.001) and p70S6K levels (-47%, p&amp;lt;0.05). In EDL, swimming lowered MuRF-1 levels (-23%, p&amp;lt;0.01), indicating specific responses to exercise across muscle types. Dex-induced muscle mass loss was lower after a 4-day preparatory exercise procedure followed by prolonged exercise (p&amp;lt;0.001 for both muscles). Swimming in Dex-treated rats decreased pAKT (-52%, p&amp;lt;0.01) in SOL and increased pmTOR (+52%, p&amp;lt;0.01) in EDL.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>Dex treatment reduces skeletal muscle mass, regardless of fiber composition. These changes relate to oxidative stress and an imbalance in iron metabolism, but differences between muscle types in the proteolysis\/synthesis signaling pathway highlight contrasting responses across muscle types. Acute prolonged swimming, preceded by a 4-day preparatory procedure, attenuates the adverse effects of Dex treatment.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fphys.2026.1890376","type":"journal-article","created":{"date-parts":[[2026,9,22]],"date-time":"2026-09-22T04:22:53Z","timestamp":1790050973000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["The effect of acute prolonged swimming on skeletal muscle metabolism in different muscle types of rats after nine days of dexamethasone treatment"],"prefix":"10.3389","volume":"17","author":[{"given":"Damian Jozef","family":"Flis","sequence":"first","affiliation":[{"name":"Department of Pharmaceutical Pathophysiology, Faculty of Pharmacy, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bartosz","family":"Cedro","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Pathophysiology, Faculty of Pharmacy, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alicja","family":"Piekarska","sequence":"additional","affiliation":[{"name":"Department of Pharmaceutical Pathophysiology, Faculty of Pharmacy, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andzelika","family":"Borkowska","sequence":"additional","affiliation":[{"name":"Department of Bioenergetics and Physiology of Exercise, Faculty of Health Sciences, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Malgorzata","family":"Halon-Golabek","sequence":"additional","affiliation":[{"name":"Department of Physiotherapy, Faculty of Health Sciences, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ewa","family":"Rodziewicz-Flis","sequence":"additional","affiliation":[{"name":"Department of Physiotherapy, Gdansk University of Physical Education and Sport","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jedrzej","family":"Antosiewicz","sequence":"additional","affiliation":[{"name":"Department of Bioenergetics and Physiology of Exercise, Faculty of Health Sciences, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wieslaw","family":"Ziolkowski","sequence":"additional","affiliation":[{"name":"Department of Rehabilitation Medicine, Faculty of Health Sciences, Medical University of Gdansk","place":["Gdansk, Poland"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,22]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1016\/s0076-6879(84)05016-3","article-title":"Catalase in vitro","volume":"105","author":"Aebi","year":"1984","journal-title":"Methods Enzymol."},{"key":"B2","doi-asserted-by":"publisher","first-page":"123","DOI":"10.1007\/s00424-003-1226-5","article-title":"Regulation of type IV collagen gene expression and degradation in fast and slow muscles during dexamethasone treatment and exercise","volume":"448","author":"Ahtikoski","year":"2004","journal-title":"Pflugers Arch."},{"key":"B3","doi-asserted-by":"publisher","first-page":"457","DOI":"10.1016\/s0891-5849(02)00842-0","article-title":"Ferritin, iron homeostasis, and oxidative damage","volume":"33","author":"Arosio","year":"2002","journal-title":"Free Radic. 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