title: Osteochondral angiogenesis in rat mandibular condyles with osteoarthritis-like changes.
abstract: OBJECTIVE
  To investigate angiogenesis at the osteochondral junction and changes in expression of pro- and anti-angiogenic factors in rat mandibular condyles with osteoarthritis-like changes.
  
  
  METHODS
  In order to evoke osteoarthritis-like lesions in mandibular condyles, disordered occlusion was created experimentally in rats. Osteochondral vascularity was assessed histologically at 20 and 24 weeks. Protein and mRNA levels of pro-angiogenic factors including vascular endothelial growth factor (VEGF), connective tissue growth factor (CTGF) and matrix metalloproteases 9 (MMP9), and anti-angiogenic factor chondromodulin-I (CHM-I) were investigated by means of immunohistochemical staining and real-time PCR.
  
  
  RESULTS
  Osteochondral angiogenesis was demonstrated as increased numbers of vascular channels terminating in the calcified cartilage and non-calcified cartilage in 20- and 24-week experimental groups compared with controls (all P<0.05). In the experimental groups, VEGF, CTGF and MMP9 were highly expressed in the tissues adjacent to the osteochondral junction. However, CHM-I was more expressed in the superior but not deep hypertrophic chondrocytes. Compared to their age-matched controls, the protein levels of VEGF and CTGF were higher in 20-week experimental group, and the protein and mRNA levels of CTGF, MMP-9, and CHM-I increased in the 24-week experimental group (all P<0.05).
  
  
  CONCLUSIONS
  In the present rat model, osteochondral angiogenesis was observed in mandibular condyles with osteoarthritis-like changes, accompanied with local upregulation of VEGF, CTGF and MMP9. Although the increase in CHM-I may moderate pro-angiogenic factors effects in the superior cartilage, the deficiency of deep hypertrophic chondrocytes to express CHM-I may permit vascular invasion into condylar cartilage.
authors.affiliation: Department of Orthodontics, School of Stomatology, Fourth Military Medical University, No. 145 Changle West Road, Xi'an 710032, China.
authors.forename: Qing-Yu
authors.initials: QY
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Dai
authors.forename: Bin
authors.initials: B
authors.lastname: Kuang
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Shi-Bin
authors.initials: SB
authors.lastname: Yu
authors.forename: Yin-Zhong
authors.initials: YZ
authors.lastname: Duan
authors.forename: Mei-Qing
authors.initials: MQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D055513:Connective Tissue Growth Factor / Q000378:metabolism; D005260:Female; D007150:Immunohistochemistry; D008335:Mandibular Condyle / Q000098:blood supply* / Q000378:metabolism* / Q000473:pathology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000473:pathology*; D010003:Osteoarthritis / Q000523:psychology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D015415:Biomarkers; D042461:Vascular Endothelial Growth Factor A; D055513:Connective Tissue Growth Factor; D020780:Matrix Metalloproteinase 9