bFGF influences human articular chondrocyte differentiation.
BACKGROUND
The possible functional role of basic fibroblast growth factor (bFGF) in regulating the mitotic and metabolic activity of primary human articular chondrocytes was investigated.


METHODS
[EF1]Chondrocytes were enzymatically isolated from femoral head cartilage, and were cultured in vitro in monolayer. bFGF-dependent cell proliferation, production of collagen type II and aggrecan were monitored 10 days after isolation. Furthermore, effect of bFGF on cell cycle, cell morphology, and mRNA expression of integrins and chondrogenic markers determined by real time PCR were analyzed.


RESULTS
bFGF concentrations in supernatants of primary human articular chondrocytes peaked immediately after isolation and then declined. In a dose-dependent manner, bFGF enhanced cell amplification and viability. BFGF induced a decrease in the apoptotic cell population, while the number of proliferating cells remained unchanged. Supplementation of cell culture with bFGF reduced collagen type II mRNA by 49%, but increased expression of the integrin alpha(2) by 70%. bFGF did not significantly regulate the integrins alpha(1), alpha(5), alpha(10), alpha(v) and type I collagen. bFGF reduced the amount of collagen type II by 53%, which was correlated with diminished mRNA production. Monolayer cultured chondrocytes secreted significant amounts of aggrecan that decreased over time. Secretion of this cartilage-specific marker was further reduced by the addition of bFGF.


CONCLUSIONS
These findings highlight the potential role of bFGF as an endogenous chondrocyte mediator that can enhance cell amplification and regulate cell differentiation.
Schmal
H
H
Department of Orthopedics and Traumatology, University of Freiburg Medical Center, Freiburg, Germany. hagen.schmal@freenet.de
Zwingmann
J
J
Fehrenbach
M
M
Finkenzeller
G
G
Stark
G B
GB
Südkamp
N P
NP
Hartl
D
D
Mehlhorn
A T
AT
D053674:Aggrecans / Q000235:genetics / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D016023:Integrins / Q000235:genetics / Q000378:metabolism; D008858:Microscopy, Phase-Contrast; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
D053674:Aggrecans; D024043:Collagen Type II; D016023:Integrins; D012333:RNA, Messenger; D016222:Fibroblast Growth Factor 2