{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T16:33:56Z","timestamp":1786120436633,"version":"build-2736575974"},"reference-count":0,"publisher":"Universa BV","issue":"2","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Acta Orthop Belg"],"abstract":"<jats:p>Klotho is an anti-aging protein involved in phosphate homeostasis, oxidative stress regulation, and tissue regeneration. Although circulating Klotho levels decline with chronological aging, its response to acute disuse- induced skeletal muscle alterations remains unclear. In this experimental study, sixteen male Wistar rats (3 months old) were randomly assigned to a control group (n = 8) or an intermittent hindlimb unloading group (3 h\/day for 15 consecutive days) (n = 8). Skeletal muscle morphology was evaluated in the extensor digitorum longus (EDL) and soleus muscles using hematoxylin\u2013eosin staining, and muscle fiber cross-sectional area (CSA) was quantified with ImageJ software. Interstitial connective tissue changes were qualitatively assessed using Masson\u2019s trichrome staining, and serum Klotho concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Intermittent unloading induced histological features consistent with early disuse-associated muscle remodeling in both EDL and soleus muscles, accompanied by a modest reduction in muscle fiber CSA compared with controls. Serum Klotho levels were significantly lower in the unloading group (7.44 \u00b1 0.54 vs 8.21 \u00b1 0.81, p = 0.045), and a moderate positive correlation was observed between circulating Klotho concentrations and mean muscle fiber CSA (r = 0.58, p = 0.02). Mild interstitial connective tissue expansion was qualitatively noted in the soleus muscle following unloading. These findings suggest that short-term intermittent hindlimb unloading in young adult rats is associated with reduced circulating Klotho levels and mild skeletal muscle remodeling. Serum Klotho may represent a candidate biomarker of early disuse-associated muscle alterations; however, further studies are required to confirm its clinical applicability. These results may have potential implications for orthopedic conditions characterized by immobilization, including fracture treatment, casting, and postoperative rehabilitation.<\/jats:p>","DOI":"10.52628\/92.2.15471","type":"journal-article","created":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T21:12:14Z","timestamp":1786050734000},"source":"Crossref","is-referenced-by-count":0,"title":["Reduced Serum Klotho Levels in Disuse-Induced Skeletal Muscle Atrophy: An Experimental Study Related to Orthopedic Immobilization"],"prefix":"10.52628","volume":"92","author":[{"given":"S.","family":"KEY","sequence":"first","affiliation":[{"name":"Department of Orthopedics, Faculty of Medicine, F\u0131rat University, 23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u00d6.","family":"ESMEZ","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Elaz\u0131\u011f Fethi Sekin City Hospital, 23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"AGAR","sequence":"additional","affiliation":[{"name":"Department of Orthopedics, Faculty of Medicine, F\u0131rat University, 23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"O. S.","family":"TANYERI","sequence":"additional","affiliation":[{"name":"Department of Physiology, F\u0131rat University,23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G.","family":"ARKALI","sequence":"additional","affiliation":[{"name":"Department of Physiology, F\u0131rat University,23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S.","family":"\u00c7ERIBA\u015eI","sequence":"additional","affiliation":[{"name":"Department of Pathology, F\u0131rat University,23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"A.","family":"Y\u00dcCE","sequence":"additional","affiliation":[{"name":"Department of Physiology, F\u0131rat University,23100, Elaz\u0131\u011f, T\u00fcrkiye"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"27062","published-online":{"date-parts":[[2026,8]]},"container-title":["Acta Orthopaedica Belgica"],"original-title":[],"deposited":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T21:12:20Z","timestamp":1786050740000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.actaorthopaedica.be\/archive\/volume-92\/summer\/experimental-basic-science-research\/reduced-serum-klotho-levels-in-disuse-induced-skeletal-muscle-atrophy-an-experimental-stud\/"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8]]},"references-count":0,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,8]]}},"URL":"https:\/\/doi.org\/10.52628\/92.2.15471","relation":{},"ISSN":["0001-6462"],"issn-type":[{"value":"0001-6462","type":"print"}],"subject":[],"published":{"date-parts":[[2026,8]]}}}