{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T20:02:34Z","timestamp":1784750554797,"version":"3.55.0"},"reference-count":27,"publisher":"Public Library of Science (PLoS)","issue":"1","license":[{"start":{"date-parts":[[2021,1,28]],"date-time":"2021-01-28T00:00:00Z","timestamp":1611792000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Osteoarthritis (OA) is one of the major causes of chronic pain in dogs. However, the pathogenesis of OA has not been fully understood in dogs. The objective of this study was to comprehensively investigate the mRNA expression levels of proinflammatory cytokines, inflammatory mediators, nerve growth factor and its receptor, and matrix metalloproteinases in the synovium of dogs with spontaneous OA as well as to elucidate their relationships with the severity of synovitis. Dogs that were diagnosed with stifle OA on the basis of radiographic findings were included, and the degree of synovitis was observed using stifle arthroscopy. The dogs were assigned to two different groups depending on their synovitis scores: the low-grade group (score of 1 or 2; n = 8) and high-grade group (score of 3 to 5; n = 18). The dogs showing no evidence of orthopedic disease were included in the control group (n = 6). Synovial tissue samples were collected from the sites at which synovitis scores were assessed using arthroscopy. Total RNA was extracted from the collected synovial tissue, and cDNA was synthesized. Subsequently, RT-qPCR were performed using canine-specific primer sets for <jats:italic>IL1B<\/jats:italic>, <jats:italic>IL6<\/jats:italic>, <jats:italic>CXCL8<\/jats:italic>, <jats:italic>TNF<\/jats:italic>, <jats:italic>TGFB1<\/jats:italic>, <jats:italic>PTGS2<\/jats:italic>, <jats:italic>PTGES<\/jats:italic>, <jats:italic>MMP3<\/jats:italic>, <jats:italic>MMP13<\/jats:italic>, <jats:italic>NGF<\/jats:italic>, <jats:italic>NTRK1<\/jats:italic>, and <jats:italic>PTGER4<\/jats:italic>. Expression levels of <jats:italic>IL1B<\/jats:italic>, <jats:italic>IL6<\/jats:italic>, <jats:italic>CXCL8<\/jats:italic>, and <jats:italic>MMP13<\/jats:italic> were significantly higher in the high-grade group than in the control group. In addition, expression levels of <jats:italic>IL1B<\/jats:italic>, <jats:italic>CXCL8<\/jats:italic>, <jats:italic>TNF<\/jats:italic>, and <jats:italic>PTGS2<\/jats:italic> were significantly higher in the high-grade group than in the low-grade group. Expression levels of <jats:italic>IL1B<\/jats:italic>, <jats:italic>IL6<\/jats:italic>, <jats:italic>CXCL8<\/jats:italic>, <jats:italic>TNF<\/jats:italic>, <jats:italic>PTGS2<\/jats:italic>, and <jats:italic>PTGER4<\/jats:italic> showed significant positive correlation with synovitis score. In conclusion, all mRNA expression levels in the synovial membrane varied according to the degree of synovitis in dogs with spontaneous OA. Thus, this study may partially elucidate the pathogenesis of synovitis in dogs with spontaneous OA.<\/jats:p>","DOI":"10.1371\/journal.pone.0246188","type":"journal-article","created":{"date-parts":[[2021,1,28]],"date-time":"2021-01-28T19:31:06Z","timestamp":1611862266000},"page":"e0246188","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":7,"title":["Variations in gene expression levels with severity of synovitis in dogs with naturally occurring stifle osteoarthritis"],"prefix":"10.1371","volume":"16","author":[{"given":"Atsushi","family":"Yamazaki","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2123-0716","authenticated-orcid":true,"given":"Kazuya","family":"Edamura","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuma","family":"Tomo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mamiko","family":"Seki","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kazushi","family":"Asano","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2021,1,28]]},"reference":[{"key":"pone.0246188.ref001","first-page":"699","article-title":"Osteoarthritis. 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