Sequential changes in transforming growth factor (TGF)-beta1 concentration in synovial fluid and mRNA expression of TGF-beta1 receptors in chondrocytes after immobilization of rabbit knees

J Bone Miner Metab. 2001;19(4):228-35. doi: 10.1007/s007740170025.

Abstract

We have previously reported that a combination of transforming growth factor (TGF)-beta1 and basic fibroblast growth factor (bFGF) synergistically increases the proliferation of chondrocytes obtained from knee joint immobilized for 7-14 days in male Japanese white rabbits. In the present study, we performed experiments with chondrocytes and syn ovial fluid obtained from rabbit knees immobilized for 0-42 days, to clarify the sequential changes in TGF-beta1 and bFGF concentrations in synovial fluid and the mRNA expression of TGF-beta1 receptor type I (RI) and II (RII) in chondrocytes after immobilization. The combination of TGF-beta1 and bFGF had a synergistic effect on the proliferation of chondrocytes obtained from knee joints immobilized for 7-14 days. The concentration of TGF-beta1 in synovial fluid was significantly higher (up to 3.6-fold) at 7-28 days after immobilization compared with that at 2 days. The mRNA for RI and RII was expressed during the whole immobilization period. The con centration of bFGF was kept at the same level at 2-7 days after immobilization, and gradually decreased thereafter. In the early stages of degenerated cartilage, up to 14 days after immobilization, the concentrations of both TGF-beta1 and bFGF were higher in the synovial fluid and mRNA expression of TGF-beta1 receptors in chondrocytes was kept.

MeSH terms

  • Activin Receptors, Type I / genetics
  • Animals
  • Cell Division / drug effects
  • Cells, Cultured
  • Chondrocytes / cytology
  • Chondrocytes / drug effects
  • Chondrocytes / metabolism*
  • Drug Synergism
  • Fibroblast Growth Factor 2 / administration & dosage
  • Fibroblast Growth Factor 2 / metabolism
  • Fibroblast Growth Factor 2 / pharmacology
  • Gene Expression
  • Immobilization
  • Knee Joint / cytology
  • Knee Joint / metabolism
  • Male
  • Protein-Serine-Threonine Kinases
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism*
  • Rabbits
  • Receptor, Transforming Growth Factor-beta Type I
  • Receptor, Transforming Growth Factor-beta Type II
  • Receptors, Transforming Growth Factor beta / genetics*
  • Synovial Fluid / metabolism*
  • Time Factors
  • Transforming Growth Factor beta / administration & dosage
  • Transforming Growth Factor beta / metabolism*
  • Transforming Growth Factor beta / pharmacology

Substances

  • RNA, Messenger
  • Receptors, Transforming Growth Factor beta
  • Transforming Growth Factor beta
  • Fibroblast Growth Factor 2
  • Protein-Serine-Threonine Kinases
  • Activin Receptors, Type I
  • Receptor, Transforming Growth Factor-beta Type I
  • Receptor, Transforming Growth Factor-beta Type II