Fibroblast growth factor stimulates colony formation of differentiated chondrocytes in soft agar

Abstract

The effect of fibroblast growth factor (FGF) on the growth of chondrocytes in soft agar was examined. FGF induced colony formation by chick embryo and rabbit chondrocytes. The colony-forming efficiency of FGF-exposed chondrocytes was similar to that of Rous sarcoma virus-transformed chondrocytes (15-20%). Other mitogenic agents tested, such as epidermal growth factor, insulin, insulin-like growth factor-l, and platelet-derived growth factor, induced very low levels of colony formation. The induction of growth in soft agar of chondrocytes by FGF was not due to cells' phenotypic transformation, because chondrocytes grown in soft agar with FGF retained the ability to synthesize cartilage-characteristic proteoglycan. FGF did not induce growth in soft agar of chondrocytes whose phenotypic expression was suppressed by retinoic acid or 5-bromodeoxyuridine. In addition, FGF did not induce growth in soft agar of primary fibroblasts and normal rat kidney (NRK) cells. These results suggest that FGF selectively stimulates growth of differentiated chondrocytes in soft agar.

Articular cartilage repair: Rabbit experiments with a collagen gel-biomatrix and chondrocytes cultured in it

“…Allogeneic chondrocytes can be isolated and multiplied in vitro, without loss of their differentiated phenotype, by using three-dimensional gel culture conditions (Kimura et al 1984) and/or specific growth factors (Kato et al 1987, Morales and Roberts 1988, Wakitani et al 1997. The results of a graft of chondrocytes in the hardened gel format we describe appear to be as good as those for isogeneic grafts (Noguchi et al 1994).…”

Fibroblast growth factor stimulates bone formation Bone induction studied in rats

“…Cartilage proliferation may have been directly stimulated as demonstrated invitro (Kato et al 1987). Because FGF is a potent stimulator of capillary formation (Montesano et al 1986), it may have facilitated endochondral ossification of the cartilage, which requires vascular supply.…”

“…It is known to stimulate colony formation by anchorage-independent chondroblasts in vitro (Kato et al 1987). Further, FGF is a potent stimulant of capillary formation (Montesano et al 1986).…”

Potent mitogenic effects of parathyroid hormone (PTH) on embryonic chick and rabbit chondrocytes. Differential effects of age on growth, proteoglycan, and cyclic AMP responses of chondrocytes to PTH.

“…In this work, we ( 12). Chicken cartilages were incubated at 370C for 1 h in 10 ml ofPBS (calcium-and magnesium-free) containing 2.5 mg/ml of trypsin.…”