Monolayer, tridimensional and immortalized cell line cultures as models in pharmacology and toxicology

The articular cartilage located in movable joints can be divided into cellular and intercellular components. This latter category, also called the extracellular matrix, is responsible for the mechanical properties of cartilage and results from the functional activity of the cartilaginous cells, the chondrocytes. Through changes in their metabolism, chondrocytes are able to modify the composition of cartilage in response to physiological, pathological and pharmacotoxicological stimuli. The culture of articular chondrocytes is therefore important in biological research and various methods have been proposed. Models in vitro of normal and pathological chondrocytes are now described. Normal culture can be studied in organ explants, monolayers and various types of tridimensional culture. Chondrocytes immortalized by gene transfection will provide a further model of normal cells when progress has been made in the maintenance of differentiation. Models of pathological cells involve normal cultured chondrocytes treated with cytokines or oxygen free radicals, or rendered senescent by successive passages. Such models are useful in pharmacological and toxicological research. The advantages and limitations of these different models of cultured articular chondrocytes are discussed.