title: [Activation of insulin-like growth factor 1 gene expression in growing rat condyle by functional mandibular protrusion].
abstract: OBJECTIVE
  We studied the changes of the IGF-1 mRNA expression in condylar cartilage to elucidate the biomolecular mechanism of mandibular advancement.
  
  
  METHODS
  Sixty 5-week-old male rats were randomly divided into experimental and control groups. The mimic functional appliances were used in experimental group. The rats were sacrificed after 1, 3, 7, 14, 21 and 28 days to study the expression of IGF-1 mRNA by in situ hybridization.
  
  
  RESULTS
  The results showed IGF-1 mRNA expression in the condylar cartilage. The transitional and maturational layers had the most abundant IGF-1 mRNA, and the IGF-1 mRNA abundance of germinal layer is higher than that of synovial and fibrous layers. Functional mandibular protrusion activated the IGF-1 mRNA expression and it began to increase after 3 days of the experiment, and the changes were most significant in 7-14 days.
  
  
  CONCLUSIONS
  This suggested that the condylar cartilage growth and remolding after functional protrusion might be caused by IGF-1 gene expression activation.
authors.affiliation: School of Stomatology, West China University of Medical Sciences, Chengdu 610041.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhou
authors.forename: S
authors.initials: S
authors.lastname: Luo
authors.forename: C
authors.initials: C
authors.lastname: Liu
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008297:Male; D008335:Mandibular Condyle / Q000378:metabolism*; D009967:Orthodontic Appliances; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I