title: [Effect of decreased bite force on the temporal and spatial expression of type I collagen mRNA in rat molar periodontal ligament].
abstract: OBJECTIVE
  The aim of this study was to observe the effect of decreased bite force on type I collagen mRNA in periodontal ligament (PDL) and probe into the molecular mechanism of the change in type I collagen mRNA.
  
  
  METHODS
  Animal models were established by extracting left maxillary molars of rats. In situ hybridization was applied.
  
  
  RESULTS
  The results showed that under decreased bite force, the expression level of type I collagen mRNA decreased at the sixth hour (49.7 +/- 11.1) (P < 0.05), reached the nadir on the second day (23.7 +/- 8.6), began to get over on the third day (43.1 +/- 10.3), and reached a relatively high level at the second week(56.3 +/- 9.8), but it was still lower than that of the normal bite force group (91.4 +/- 16.0)(P < 0.05); the expression of type I collagen mRNA near the cementum was higher than that near the alveolar bone.
  
  
  CONCLUSIONS
  These results indicate that the expression level of type I collagen mRNA is closely related to bite force.
authors.affiliation: Department of Prothodontics, School of Stomatology, WCUMS, Chengdu 610041, China.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.forename: G
authors.initials: G
authors.lastname: Li
authors.forename: H
authors.initials: H
authors.lastname: Wang
mesh_terms: D000818:Animals; D001732:Bite Force; D024042:Collagen Type I / Q000096:biosynthesis* / Q000235:genetics; D003739:Dental Cementum / Q000378:metabolism; D008297:Male; D008963:Molar; D010513:Periodontal Ligament / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D024042:Collagen Type I; D012333:RNA, Messenger