We conclude that the inhibition of MMPs by tetracyclines occurs mainly via down-regulation of the respective gene expression.

In conclusion, our studies indicate that NSAIDs preferentially inhibit tPA expression by bovine articular chondrocytes. By increasing the production of PAI-1 at therapeutical concentrations meloxicam could reduce PA activity, whereas the other NSAIDs tested mainly enhanced the release of this inhibitor from the extracellular matrix. In how far this would affect the enzyme-inhibitor balance within cartilage has to be determined in further studies.

No abstract