{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,26]],"date-time":"2026-03-26T19:39:22Z","timestamp":1774553962700,"version":"3.50.1"},"reference-count":34,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2020,5,15]],"date-time":"2020-05-15T00:00:00Z","timestamp":1589500800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Interleukin-6 (IL-6) is widely accepted to stimulate osteoclasts. Our aim in this study was to examine whether the inhibitory effect of IL-6 on bone loss and skeletal pain associated with osteoporosis in hindlimb-unloaded (HU) mice in comparison with bisphosphonate. Eight-week-old male ddY mice were tail suspended for 2 weeks. Starting immediately after reload, vehicle (HU group), alendronate (HU-ALN group), or anti-IL-6 receptor antibody (HU-IL-6i group) was injected subcutaneously. After a 2-week treatment, pain-related behavior was examined using von Frey filaments. The bilateral distal femoral and proximal tibial metaphyses were analyzed three-dimensionally with micro-computed tomography. Calcitonin gene-related peptide (CGRP) expressions in dorsal root ganglion (DRG) neurons innervating the hindlimbs were examined using immunohistochemistry. HU mice with tail suspension developed bone loss. The HU mice showed mechanical hyperalgesia in the hindlimbs and increased CGRP immunoreactive neurons in the L3-5 DRG. Treatment with IL-6i and ALN prevented HU-induced mechanical hyperalgesia and upregulation of CGRP expressions in DRG neurons. Furthermore, ALN but not IL-6i prevented HU-induced bone loss. In summary, treatment with IL-6i prevented mechanical hyperalgesia in hindlimbs and suppressed CGRP expressions in DRG neurons of osteoporotic models. The novelty of this research suggests that IL-6 is one of the causes of immobility-induced osteoporotic pain regardless improvement of bone loss.<\/jats:p>","DOI":"10.3390\/ijms21103521","type":"journal-article","created":{"date-parts":[[2020,5,15]],"date-time":"2020-05-15T10:53:59Z","timestamp":1589540039000},"page":"3521","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Functional Block of Interleukin-6 Reduces a Bone Pain Marker But Not Bone Loss in Hindlimb-Unloaded Mice"],"prefix":"10.3390","volume":"21","author":[{"given":"Hiroki","family":"Wakabayashi","sequence":"first","affiliation":[{"name":"Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Gaku","family":"Miyamura","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nobuto","family":"Nagao","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sho","family":"Kato","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2159-5942","authenticated-orcid":false,"given":"Yohei","family":"Naito","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0474-4368","authenticated-orcid":false,"given":"Akihiro","family":"Sudo","sequence":"additional","affiliation":[{"name":"Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"572","DOI":"10.1016\/j.jbspin.2011.04.007","article-title":"Pathophysiology of bone loss in disuse osteoporosis","volume":"78","author":"Alexandre","year":"2011","journal-title":"Jt. Bone Spine"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/S1090-3801(02)00071-X","article-title":"Disuse and deconditioning in chronic low back pain: Concepts and hypotheses on contributing mechanisms","volume":"7","author":"Verbunt","year":"2003","journal-title":"Eur. J. Pain"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1196","DOI":"10.1152\/japplphysiol.00997.2015","article-title":"Hindlimb unloading: Rodent analog for microgravity","volume":"120","author":"Globus","year":"2016","journal-title":"J. Appl. Physiol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"489","DOI":"10.1016\/0021-9290(92)90089-J","article-title":"The physical and mechanical effects of suspension-induced osteopenia on mouse long bones","volume":"25","author":"Simske","year":"1992","journal-title":"J. Biomech."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1063","DOI":"10.1016\/j.jos.2018.06.002","article-title":"The effects of bisphosphonate on pain-related behavior and immunohistochemical analyses in hindlimb-unloaded mice","volume":"23","author":"Nakagawa","year":"2018","journal-title":"J. Orthop. Sci."},{"key":"ref_6","first-page":"12","article-title":"Effects of estrogen on tail suspension-induced disuse atrophy in ovariectomized rats: Evaluation of the expression of interleukin-6 mRNA in the femur","volume":"45","author":"Ohmori","year":"2001","journal-title":"Environ. Med."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1007\/s00223-001-2034-6","article-title":"Rat hindlimb unloading by tail suspension reduces osteoblast differentiation, induces IL-6 secretion, and increases bone resorption in ex vivo cultures","volume":"70","author":"Grano","year":"2002","journal-title":"Calcif. Tissue Int."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"900","DOI":"10.1093\/rheumatology\/ket468","article-title":"The effect of tocilizumab on bone mineral density in patients with methotrexate-resistant active rheumatoid arthritis","volume":"53","author":"Kume","year":"2014","journal-title":"Rheumatology"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"849","DOI":"10.1016\/S0899-9007(02)00895-X","article-title":"Calcium and bone metabolism during space flight","volume":"18","author":"Smith","year":"2002","journal-title":"Nutrition"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"1006","DOI":"10.1359\/JBMR.040307","article-title":"Cortical and trabecular bone mineral loss from the spine and hip in long-duration spaceflight","volume":"19","author":"Lang","year":"2004","journal-title":"J. Bone Miner. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/8756-3282(86)90682-4","article-title":"Immobilization-associated osteoporosis in primates","volume":"7","author":"Young","year":"1986","journal-title":"Bone"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"18934","DOI":"10.1074\/jbc.M115.642090","article-title":"Inhibition of osteocyte apoptosis prevents the increase in osteocytic receptor activator of nuclear factor \u03baB ligand (RANKL) but does not stop bone resorption or the loss of bone induced by unloading","volume":"290","author":"Plotkin","year":"2015","journal-title":"J. Biol. Chem."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2347","DOI":"10.1007\/s00198-011-1842-4","article-title":"Prevention of disuse osteoporosis in rats by Cordyceps sinensis extract","volume":"23","author":"Qi","year":"2012","journal-title":"Osteoporos. Int."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.cyto.2014.05.024","article-title":"Interleukin-6 and its receptors: A highly regulated and dynamic system","volume":"70","author":"Wolf","year":"2014","journal-title":"Cytokine"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1016\/S0165-5728(97)00257-9","article-title":"Calcitonin gene-related peptide potentiates LPS-induced IL-6 release from mouse peritoneal macrophages","volume":"84","author":"Tang","year":"1998","journal-title":"J. Neuroimmunol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"9367","DOI":"10.3892\/mmr.2017.7779","article-title":"Calcitonin gene-related peptide induces IL-6 expression in RAW264.7 macrophages mediated by mmu_circRNA_007893","volume":"16","author":"Deng","year":"2017","journal-title":"Mol. Med. Rep."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1111\/j.1471-4159.2006.03856.x","article-title":"Increased calcitonin gene-related peptide in neuroma and invading macrophages is involved in the up-regulation of interleukin-6 and thermal hyperalgesia in a rat model of mononeuropathy","volume":"98","author":"Ma","year":"2006","journal-title":"J. Neurochem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1006\/cimm.2001.1795","article-title":"Bone marrow-derived macrophages express functional CGRP receptors and respond to CGRP by increasing transcription of c-fos and IL-6 mRNA","volume":"209","author":"Fernandez","year":"2001","journal-title":"Cell. Immunol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1508","DOI":"10.1002\/jor.22925","article-title":"Interleukin-6 and interleukin-6 receptor expression, localization, and involvement in pain-sensing neuron activation in a mouse intervertebral disc injury model","volume":"33","author":"Sainoh","year":"2015","journal-title":"J. Orthop. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1016\/j.biocel.2016.08.003","article-title":"Cell-specific paracrine actions of IL-6 family cytokines from bone, marrow and muscle that control bone formation and resorption","volume":"79","author":"Sims","year":"2016","journal-title":"Int. J. Biochem. Cell Biol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"339","DOI":"10.1038\/368339a0","article-title":"Impaired immune and acute-phase responses in interleukin-6-deficient mice","volume":"368","author":"Kopf","year":"1994","journal-title":"Nature"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1172\/JCI19872","article-title":"Glycoprotein 130 regulates bone turnover and bone size by distinct downstream signaling pathways","volume":"113","author":"Sims","year":"2004","journal-title":"J. Clin. Investig."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1196\/annals.1402.018","article-title":"Osteocytes as dynamic multifunctional cells","volume":"1116","author":"Bonewald","year":"2007","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"120","DOI":"10.1016\/j.bone.2018.04.015","article-title":"IL-6 trans-signalling mediates trabecular, but not cortical, bone loss after ovariectomy","volume":"112","author":"Lazzaro","year":"2018","journal-title":"Bone"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1016\/S0165-2478(02)00202-X","article-title":"Characterization of anti-mouse interleukin-6 receptor antibody","volume":"84","author":"Okazaki","year":"2002","journal-title":"Immunol. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"658","DOI":"10.1007\/s00223-019-00521-4","article-title":"Interleukin-6 inhibitor suppresses hyperalgesia without improvement in osteoporosis in a mouse pain model of osteoporosis","volume":"104","author":"Wakabayashi","year":"2019","journal-title":"Calcif. Tissue Int."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1046\/j.1365-201X.2002.01040.x","article-title":"A rat resistance exercise regimen attenuates losses of musculoskeletal mass during hindlimb suspension","volume":"176","author":"Fluckey","year":"2002","journal-title":"Acta Physiol. Scand."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"175","DOI":"10.3758\/BF03193146","article-title":"G*power 3: A flexible statistical power analysis program for the social, behavioral, and biomedical sciences","volume":"39","author":"Faul","year":"2007","journal-title":"Behav. Res. Methods"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"1445","DOI":"10.1007\/s00296-010-1500-8","article-title":"Induction of high-dose tolerance to the rat anti-mouse IL-6 receptor antibody in NZB\/NZW F1 mice","volume":"31","author":"Yoshida","year":"2011","journal-title":"Rheumatol. Int."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"857","DOI":"10.1002\/art.39523","article-title":"Nociceptive Sensitizers Are Regulated in Damaged Joint Tissues, Including Articular Cartilage, When Osteoarthritic Mice Display Pain Behavior","volume":"68","author":"Driscoll","year":"2016","journal-title":"Arthritis Rheumatol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1146\/annurev.pa.20.040180.002301","article-title":"Efficient analysis of experimental observations","volume":"20","author":"Dixon","year":"1980","journal-title":"Ann. Rev. Pharmacol. Toxicol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"274","DOI":"10.1007\/s00774-017-0842-7","article-title":"Decreased sensory nerve excitation and bone pain associated with mouse Lewis lung cancer in TRPV1-deficient mice","volume":"36","author":"Wakabayashi","year":"2018","journal-title":"J. Bone Miner. Metab."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"174","DOI":"10.1002\/j.1532-2149.2013.00360.x","article-title":"Nociceptive phenotype of dorsal root ganglia neurons innervating the subchondral bone in rat knee joints","volume":"18","author":"Aso","year":"2014","journal-title":"Eur. J. Pain"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"652","DOI":"10.1016\/j.jpain.2009.10.007","article-title":"Sclerotomes in the thoracic and lumbar spine, pelvis, and hindlimb bones of rats","volume":"11","author":"Takahashi","year":"2010","journal-title":"J. Pain"}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/21\/10\/3521\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:29:16Z","timestamp":1760174956000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/21\/10\/3521"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,5,15]]},"references-count":34,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["ijms21103521"],"URL":"https:\/\/doi.org\/10.3390\/ijms21103521","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,5,15]]}}}