Effect of X-ray contrast media on the action of chymopapain on the intervertebral disc: an in vitro study of cartilage degradation.

A representative selection of X-ray contrast media was tested for their effects on the action of chymopapain on cartilage proteoglycan in an in-vitro test system. Inhibition of the action of chymopapain was detected only at high concentrations of contrast media, and was more marked with ionic contrast media than with non-ionic media. A dose-response curve for the release of glycosaminoglycan by chymopapain was linear when the amount of enzyme was plotted on a logarithmic scale against glycosaminoglycan release. In view of our results, we suggest that there is no need for a delay between injection of contrast medium and enzyme, contrary to the instructions of the distributors of chymopapain, if small amounts of a non-ionic contrast medium are used.