title: [Change and Significance of RhoA/ROCK signaling pathway in the model with natural degeneration of the rat endplate chondrocytes].
abstract: OBJECTIVE
  To explore the change and Significance of RhoA/ROCK signaling pathway in the model with natural degeneration of the rat endplate chondrocytes.
  
  
  METHODS
  Endplate chondrocytes were selected by enzyme digestion and cultured in vitro to divided into control (P2 cells), naturally passaged (P5 cells) groups and treatment group (P5+ROCK Inhibitor Y27632). The phenotype of endplate chondrocytes were identified by toluidine blue stains and F-actin stains. Type II collagen, aggrecan and SOX9 genes were examed by Real-time RT-PCR to verify the degeneration model. The RhoA/ROCK signaling pathway related gene ROCK-1, ROCK-2 were detected by RT-PCR and Western blot. The actived RhoA was examed by active-RhoA detection and Western blot.
  
  
  RESULTS
  With the passaging,endplate chondrocytes completely lost the original cell morphology, the levels of type II collagen (P5/P2=0.248, P<0.001), aggrecan (P5/P2=0.172, P<0.001) and SOX9 (P5/P2 =0.499, P<0.001) significantly reduced. There is also a certain reduction of ROCK-1 (P5/P2=0.652, P<0.001), but ROCK-2 (P5/P2=2.527, P<0.001) expression increased significantly. And the active-RhoA were Significant increased too.ROCK-1 AND ROCK-2 were down-regulated in the treatment group. And type II collagen, aggrecan, SOX9 significantly increased.
  
  
  CONCLUSIONS
  The degeneration of endplate chondrocytes with decreased ROCK-1 expression but increased active-RhoA and ROCK-2 expression suggest that RhoA/ROCK signaling pathway play an important role in the in vitro degeneration of endplate chondrocytes.Modulating the expression of RhoA/ROCK signaling pathway may be a new method of solving the problem of the degeneration of intervertebral disc.
authors.affiliation: Department of Orthopedic Surgery, Yijishan Hosptial, Wannan Medical College, Wuhu 241001, China.
authors.forename: Mingming
authors.initials: M
authors.lastname: Ma
authors.affiliation: Email: xuhg@medmail.com.cn.
authors.forename: Hongguang
authors.initials: H
authors.lastname: Xu
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Zhang
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Quan
authors.initials: Q
authors.lastname: Zheng
authors.forename: Jiajia
authors.initials: J
authors.lastname: Xu
authors.forename: Xiang
authors.initials: X
authors.lastname: Shen
authors.forename: Shufeng
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000199:Actins; D053674:Aggrecans; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D019902:Chondrocytes; D024043:Collagen Type II; D015536:Down-Regulation; D051381:Rats; D015398:Signal Transduction; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein
chemical_list: D000199:Actins; D053674:Aggrecans; D024043:Collagen Type II; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein