The effects of ciprofloxacin on human chondrocytes in cell culture.

Ciprofloxacin is a highly potent antibacterial agent that is used extensively in bone and joint infections. Because of reports of potential chondro-toxicity in animals, the effects of this drug on cells derived from human cartilage were tested in liquid micromass and agarose gel cultures. An inhibition of cell proliferation as indicated by a decrease in [3H]-thymidine uptake and bromodeoxyuridine labeling at ciprofloxacin concentrations of 0.5 and 50 mg/l was found which corresponded to the therapeutic and toxic serum levels. There was no effect on proteoglycan synthesis as indicated by 35SO4 incorporation. Immunocytochemistry showed no changes in morphology or staining patterns for type-I procollagen, type-II collagen, keratan sulfate and unsulfated chondroitin. Because the amount of inhibition of DNA synthesis varied with different ciprofloxacin concentrations, this data suggests that this agent has a differential effect on newly differentiating cells and might be the basis for contraindication in pediatric patients.