Differential response of cultured rabbit articular chondrocytes (RAC) to transforming growth factor beta (TGF-beta)-evidence for a role of serum factors.
We show that addition of TGF-beta (0.01-10 ng/ml) to proliferating rabbit articular chondrocytes in presence of low level of fetal calf serum (FCS, 2%) results in a sustained decrease of cell number and DNA synthesis up to 72 h. In contrast, incubation with high serum concentration (10% FCS) induces a transient increase of cell number after 48 h without elevation of DNA synthesis. Moreover, when the factor is added in 10% FCS-containing medium, a differential effect is observed at 48 h (either increase or decrease of cell number) depending on the serum level (2 or 10%) present between 24 and 48 h. Recruitment of cells in late S-phase occurred under TGF-beta-treatment in both 2 and 10% FCS. These arrested cells may then be released by further exposure to 10% FCS-containing medium. The data show that factor(s) from the serum modulate(s) the action of TGF-beta on chondrocyte proliferation. Addition of epidermal growth factor (EGF) to the cultures in presence of 2% FCS mimicks the effects observed with 10% serum, suggesting that the serum component(s) involved in the mechanism could be of EGF type.
Vivien
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D
Laboratoire de Biochemie du Tissu Conjonctif, Université de Caen, France.
Galera
P
P
Loyau
G
G
Pujol
J P
JP
D000818:Animals; D001769:Blood; D002358:Cartilage, Articular / Q000166:cytology* / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology; D007700:Kinetics; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011817:Rabbits; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D003470:Culture Media; D010982:Platelet-Derived Growth Factor; D016212:Transforming Growth Factor beta; D004815:Epidermal Growth Factor; D004247:DNA