Effects of FGF-2 and IGF-1 on adult canine articular chondrocytes in type II collagen-glycosaminoglycan scaffolds in vitro.
OBJECTIVE
Chondrocyte-seeded tissue engineering scaffolds hold the promise of enhancing certain cartilage repair procedures. The objective of this study was to evaluate the effects of selected growth factors [fibroblast growth factor (FGF)-2 and insulin-like growth factor (IGF)-1] individually and in combination on adult canine articular chondrocyte-seeded type II collagen-glycosaminoglycan (GAG) scaffolds grown in serum-free (SF) medium.


METHODS
Approximately 500,000 second passage chondrocytes were seeded into discs of the scaffold, 4mm diameterx2 mm thick. The constructs were grown in the following media: serum-containing medium; a basal SF medium; SF with 5 ng/ml FGF-2; SF with 25 ng/ml FGF-2; SF with 100 ng/ml IGF-1; and SF with 5 ng/ml FGF-2 plus 100 ng/ml IGF-1. The DNA and GAG contents of the scaffolds were determined after 1 day and 2 weeks and the protein and GAG synthesis rates determined at 2 weeks using radiolabels. Histology and type II collagen immunohistochemistry were also performed.


RESULTS
FGF-2 at 5 ng/ml was found to substantially increase the biosynthetic activity of the cells and the accumulation of GAG. The histology demonstrated chondrocytes uniformly distributed through a matrix that stained intensely for GAG and type II collagen after only 2 weeks. Of interest were the rapid degradation of the collagen scaffold, despite the fact that the scaffold was carbodiimide cross-linked, and the contraction of the constructs. There were less pronounced effects using the higher dose of FGF-2 and the combination with IGF-1.


CONCLUSIONS
Chondrocyte-seeded type II collagen scaffolds cultured in SF medium supplemented with 5 ng/ml FGF-2 undergo contraction, demonstrate an increase in construct incorporation of radiolabeled sulfate, and display qualitative signs of chondrogenesis.
Veilleux
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VA Boston Healthcare System, Boston Campus, 150 S. Huntington Avenue, Boston, MA 02130, USA.
Spector
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M
D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018929:Cell Culture Techniques; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020219:Chondrogenesis; D024043:Collagen Type II / Q000737:chemistry; D016895:Culture Media, Serum-Free; D004247:DNA / Q000032:analysis; D004285:Dogs; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology*; D006025:Glycosaminoglycans / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D023822:Tissue Engineering / Q000379:methods*
D024043:Collagen Type II; D016895:Culture Media, Serum-Free; D006025:Glycosaminoglycans; D016222:Fibroblast Growth Factor 2; D007334:Insulin-Like Growth Factor I; D004247:DNA