title: Involvement of the MAPK pathway in the pressure-induced synovial metaplasia procedure for the temporomandibular joint.
abstract: Abnormal pressure is an important factor that contributes to bone adaptation in the temporomandibular joint (TMJ). We determined the effect of the mitogen-activated protein kinases (MAPK) pathway on the pressure-induced synovial metaplasia procedure for the TMJ, both in vitro and in vivo. Synovial fibroblasts (SFs) were exacted from rat TMJs and exposed to different hydrostatic pressures. The protein extracts were analyzed to determine the activation of ERK1/2, JNK, and p38. Surgical anterior disc displacement (ADD) was also performed on Japanese rabbits, and the proteins of TMJ were isolated to analyze pressure-induced MAPK activation after 1, 2, 4, and 8 weeks. The results showed that the activation of ERK1/2 and JNK in SFs significantly changed with increasing hydrostatic pressure, whereas p38 activation did not change. Moreover, p38 was activated in animals 1 week after surgical ADD. The levels of p38 gradually increased after 2 and 4 weeks, and then slightly decreased but remained higher than in the control 8 weeks after surgical ADD. Nevertheless, JNK was rarely activated after the ADD treatment. Our findings suggest the involvement of MAPK activation in the pressure-induced synovial metaplasia procedure with pressure loading in TMJ.
authors.affiliation: Department of Orthodontics, Hospital of Stomatology, Zhejiang University, Hangzhou, China.
authors.forename: M J
authors.initials: MJ
authors.lastname: Wu
authors.affiliation: School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: H P
authors.initials: HP
authors.lastname: Lu
authors.affiliation: School of Stomatology, Zhejiang Chinese Medical University, Hangzhou, China.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Gu
authors.affiliation: Department of Orthodontics, Hospital of Stomatology, Zhejiang University, Hangzhou, China.
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism; D006874:Hydrostatic Pressure / Q000009:adverse effects; D017746:Joint Capsule / Q000378:metabolism / Q000473:pathology; D020935:MAP Kinase Signaling System; D008679:Metaplasia; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D013704:Temporomandibular Joint / Q000378:metabolism / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases