title: [Cyclic strain promotes migration of human periodontal ligament cell via extracellular signal-regulated kinase (ERK) signaling pathway].
abstract: OBJECTIVE
  To study the effect of cyclic strain on migration of human periodontal ligament cell(hPDLC) and underlying mechanism.
  
  
  METHODS
  The cultured hPDLC were subjected to 10% or 20%-elongation magnitude cyclic strain at frequency of 0.1 Hz by FX-4000T system for 6 or 24 hours-duration respectively, while the static group serves as control. hPDLC migration was assayed by wound healing method. The expressions of matrix metalloproteinases-9 (MMP-9) and p-ERK1/2 in hPDLC without or with cyclic strain were analyzed by Western blotting. To investigate the effect of ERK signaling pathway and MMP-9 on migration of hPDLC, the cells were incubated with PD98059, a specific extracellular signal-regulated kinase (ERK) kinase inhibitor, or doxycycline, a MMP inhibitor. Then the expressions of p-ERK1/2 and MMP-9 and hPDLC migration were analyzed.
  
  
  RESULTS
  In wound healing tests, the migration of hPDLC exposed to 10% or 20%-cyclic strain at 0.1 Hz-frequency for 6 hours was not apparent but became significantly different for 24 hours (P < 0.05) compared to control. Furthermore, the 20%-elongation magnitude of cyclic strain had more remarkable effect on migration of hPDLC than 10%-elongation magnitude at 24 hours-duration (P < 0.05). Cyclic strain obviously increased the expression of MMP-9 in hPDLC (P < 0.05). PD98059 could repress not only the activation of p-ERK1/2 but also the expression of MMP-9 induced by cyclic strain in hPDLC. The migration of hPDLC enhanced by cyclic strain was repressed by DOX or PD98059 in wound healing tests.
  
  
  CONCLUSIONS
  Cyclic strain promotes the migration of hPDLC through activating ERK signaling pathway and inducing the expression of MMP-9.
authors.affiliation: Department of Stomatology, The 1st People's Hospital, Shanghai Jiao Tong University, Shanghai 200080, China. pip0003@163.com
authors.forename: Jin-song
authors.initials: JS
authors.lastname: Pan
authors.forename: Yue
authors.initials: Y
authors.lastname: Han
authors.forename: Dan-peng
authors.initials: DP
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Ying-xin
authors.initials: YX
authors.lastname: Qi
authors.forename: Zhi-qiang
authors.initials: ZQ
authors.lastname: Yan
mesh_terms: D000293:Adolescent; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004318:Doxycycline / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors / Q000494:pharmacology; D010513:Periodontal Ligament / Q000166:cytology* / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D013314:Stress, Mechanical
chemical_list: D005419:Flavonoids; D061965:Matrix Metalloproteinase Inhibitors; D047428:Protein Kinase Inhibitors; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; D004318:Doxycycline; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one