Cartilage damage as a result of hemarthrosis in a human in vitro model.

OBJECTIVE: To investigate the direct effect of blood and blood components on human cartilage in vitro.
METHODS: Healthy human articular cartilage tissue was obtained post mortem and cultured according to standard procedures. The harmful effects of whole blood and various isolated blood components as well as the reversibility of these effects were assessed by means of proteoglycan synthesis and proteoglycan release.
RESULTS: Whole blood anticoagulated with heparin, coagulated blood, mononuclear cells (MNC), erythrocytes [red blood cells (RBC)] and plasma, in this order of potency, decreased proteoglycan synthesis in a dose dependent manner. The effect of the combination of MNC and RBC in concentrations equivalent to those in whole blood was significantly greater than the effect of each of these isolated components alone and did not differ from that of whole blood. Moreover, cartilage exposed for 4 days to this combination exhibited irreversible inhibition of proteoglycan synthesis. The effect was similar to that of whole blood, the opposite of that of the individual components or other combinations.
CONCLUSION: Results suggest a direct irreversible harmful effect of whole blood on cartilage, whereby MNC and RBC together are the main factors. Taking into account that the concentration of blood during hemarthrosis approaches 100% and the natural evacuation time of blood from a joint is about 4 days, our results suggest that prompt evacuation of intraarticular blood or prevention of intraarticular bleeding might be crucial in preventing cartilage damage.