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.
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.
Okazaki
R
R
Department of Radiation Biology and Health, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Sakai
A
A
Uezono
Y
Y
Ootsuyama
A
A
Kunugita
N
N
Nakamura
T
T
Norimura
T
T
D030201:Activin Receptors, Type I / Q000235:genetics; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004357:Drug Synergism; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D015870:Gene Expression; D007103:Immobilization; D007719:Knee Joint / Q000166:cytology / Q000378:metabolism; D008297:Male; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D011817:Rabbits; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*; D013582:Synovial Fluid / Q000378:metabolism*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000378:metabolism* / Q000494:pharmacology
D012333:RNA, Messenger; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D016222:Fibroblast Growth Factor 2; D017346:Protein Serine-Threonine Kinases; D030201:Activin Receptors, Type I; D000077293:Receptor, Transforming Growth Factor-beta Type I; D000077294:Receptor, Transforming Growth Factor-beta Type II