title: Mechanical loading induced expression of bone morphogenetic protein-2, alkaline phosphatase activity, and collagen synthesis in osteoblastic MC3T3-E1 cells.
abstract: BACKGROUND
  Bone morphogenetic protein (BMP)-2, alkaline phosphatase (ALP), and collagen type I are known to play a critical role in the process of bone remodeling. However, the relationship between mechanical strain and the expression of BMP-2, ALP, and COL-I in osteoblasts was still unknown. The purpose of this study was to investigate the effects of different magnitudes of mechanical strain on osteoblast morphology and on the expression of BMP-2, ALP, and COL-I.
  
  
  METHODS
  Osteoblast-like cells were flexed at four deformation rates (0, 6%, 12%, and 18% elongation). The expression of BMP-2 mRNA, ALP, and COL-I in osteoblast-like cells were determined by real-time quantitative reverse transcription polymerase chain reaction, respectively. The results were subjected to analysis of variance (ANOVA) using SPSS 13.0 statistical software.
  
  
  RESULTS
  The cells changed to fusiform and grew in the direction of the applied strain after the mechanical strain was loaded. Expression level of the BMP-2, ALP, and COL-I increased magnitude-dependently with mechanical loading in the experimental groups, and the 12% elongation group had the highest expression (P < 0.05).
  
  
  CONCLUSIONS
  Mechanical strain can induce morphological change and a magnitude-dependent increase in the expression of BMP-2, ALP, and COL-I mRNA in osteoblast-like cells, which might influence bone remodeling in orthodontic treatment.
authors.affiliation: Department of Stomatology, Third Hospital Affiliated to Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Hong-fei
authors.initials: HF
authors.lastname: Lu
authors.forename: Zhi-hui
authors.initials: ZH
authors.lastname: Mai
authors.forename: Ye
authors.initials: Y
authors.lastname: Xu
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: Hong
authors.initials: H
authors.lastname: Ai
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D002460:Cell Line; D003094:Collagen / Q000378:metabolism; D024042:Collagen Type I / Q000378:metabolism; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism*
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D024042:Collagen Type I; D003094:Collagen; D000469:Alkaline Phosphatase