RESPONSE OF YOUNG, OLD AND OSTEOARTHRITIC CHONDROCYTES TO GROWTH FACTOR TREATMENT: EXPERIMENTAL MODEL

Abstract

Introduction and purpose: We have studied the in-vitro response of older and osteoarthritic chondrocytes when confronted with various factors in order to analyze the possible reversion of their phenotype to that of healthy chondrocytes.

Materials and methods: The study used cartilage from young (3 months’ old) and old (7 years old) lambs with an osteoarthritic pathology. The latter group was obtained by means of a meniscectomy after a two-month evolution. Cells coming from the femur cartilage were isolated by means of collagenase digestion and cultured in a single layer using a DMEM culture medium supplemented with 10% fetal serum, penicilin and streptomycin, hepes and L-cystein (Gibco-BRL®). BrdU incorporation assays were performed by means of an ELISA protocol in order to analyze the proliferation rate. Later, a gene expression analysis was conducted using RT-PCR. The treatment was carried out at a concentration of 50 ng/mL using FGFa, IGF-a, TGF-b (Peprotech Inc) and OP-1 (Stryker) growth factors, and later growth factor combinations FGFa/IGF-1, FGFa/OP-1, FGFa/TGF-b and TGF-b/OP-1.

Results and conclusions: Comparison between the three groups showed that the proliferation rate was lower in older and osteoarthritic cells. These last two groups, however, did not have the same expression pattern as the genes studied. The analysis of the response to growth factors showed that FGFa and IGF-1 were the most efficient ones, and their combination proved to be the most powerful of all.