title: Orthopedic protraction of the maxilla may affect cranial base synchondroses indicated by increased expressions of growth factors.
abstract: OBJECTIVE
  To examine the biological adaptation of cranial base synchondroses (CBS) when the maxilla was forward positioned by orthopedic force.
  
  
  METHODS
  The Department of Orthodontics at Shanghai Jiao Tong University. 50 Sprague-Dawley rats, 4 weeks of age, were divided into experimental (n=30) and control groups (n=20).
  
  
  METHODS
  An orthopedic appliance was fitted to the cranio-maxillary complex to advance the maxilla forward. The animals in the experimental group, together with the counterparts in the control group, were sacrificed at days 1, 3, 5, 7, and 14, respectively. The whole cranial base housing both the spheno-ethmoid (SES) and spheno-occipital synchondroses (SOS) was removed for tissue processing and immunotest of Sox9, Core-binding factor α 1 (Cbfa1), and vascular endothelial growth factor (VEGF), three carefully selected growth factors that are markers of chondrogenesis in different stages and its transition to endochondral ossification. Semiquantitative analysis was also conducted by using a computerizing imaging system.
  
  
  RESULTS
  The temporal tendency of the changes in the expressions of the three growth factors featured an increase from Day 3 and onwards for Cbfa1 and VEGF, and a following decline after Day 5 for Sox9. In both SES and SOS, the expressions of the three growth factors were significantly stronger in the experimental groups than that in groups (p<0.05).
  
  
  CONCLUSIONS
  Protractive orthopedic force imposed on the maxilla provokes an enhancement of chondrogenic process in CBS.
authors.affiliation: Department of Orthodontics, College of Stomatology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: J
authors.initials: J
authors.lastname: Feng
authors.forename: N
authors.initials: N
authors.lastname: Zhao
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: A B
authors.initials: AB
authors.lastname: Rabie
authors.forename: G
authors.initials: G
authors.lastname: Shen
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D020219:Chondrogenesis / Q000502:physiology; D050659:Core Binding Factor Alpha 1 Subunit / Q000032:analysis; D003393:Cranial Sutures / Q000473:pathology*; D005004:Ethmoid Bone / Q000473:pathology; D005115:Extraoral Traction Appliances; D036341:Intercellular Signaling Peptides and Proteins / Q000032:analysis*; D008437:Maxilla / Q000473:pathology*; D023421:Models, Animal; D009777:Occipital Bone / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D055758:SOX9 Transcription Factor / Q000032:analysis; D019291:Skull Base / Q000473:pathology*; D013100:Sphenoid Bone / Q000473:pathology; D013314:Stress, Mechanical; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D036341:Intercellular Signaling Peptides and Proteins; C493717:Runx2 protein, rat; D055758:SOX9 Transcription Factor; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat