In vitro assays of chondrocyte functions: the influence of drugs and hormones

Chondrotoxicity of quinolones in vivo and in vitro

Chondrotoxicity is a rare toxicological finding which is observed in dogs after administration of quinolone antibacterials. To study this effect chondrocytes from articular cartilage of dogs were isolated, and incubated with quinolone derivatives. The effects on cell viability, mitochondrial dehydrogenase, and proteoglycan synthesis were determined. These results were compared with in vivo findings in dogs treated with these quinolones. It was concluded that inhibition of mitochondrial dehydrogenase activity and of proteoglycan synthesis are major reasons for cartilage damage. Therefore this in vitro model is capable of identifying strongly arthropathogenic quinolones without the need of performing animal studies.

Effects of sodium naproxen on differentiated human chondrocytes cultivated in clusters

The effects of different pharmacological concentrations of the non-steroidal anti-inflammatory drug (NSAID) sodium naproxen (NAP) were tested on several metabolic functions of differentiated human chondrocytes cultivated in clusters and compared with the action of acetylsalicylic acid (ASA). DNA synthesis was significantly inhibited by ASA but not by NAP. Proteoglycan production was also markedly decreased by ASA, while synthesis of type II collagen was not modified. By contrast, NAP did not affect these chondroformative processes. Both NSAIDs were potent inhibitors of prostaglandin E2 production. These results indicate that in terms of the parameters tested NAP does not lead to deleterious effects on human articular chondrocytes cultured in vitro.