THE EFFECT OF DRUGS COMMONLY USED IN THE TREATMENT OF EQUINE ARTICULAR DISORDERS ON THE ACTIVITY OF EQUINE MATRIX METALLOPROTEINASE-2 AND METALLOPROTEINASE-9

Loss of articular cartilage, which is the most important pathological lesion occurring in osteoarthritis, has been shown to be enzymatically mediated, The matrix metalloproteinases (MMPs) are a group of enzymes which have been implicated in this degradation of articular cartilage matrix. The use of pharmacological agents to inhibit this catabolic p rocess in the joint is a potential route for therapeutic intervention. The gelatinase MMPs, MMPs-2 and 9, were purified by affinity chromato graphy from equine cell cultures, The ability of phenylbutazone, fluni xin, betamethasone, dexamethasone, methylprednisolone acetate (MPA), h yaluronan, pentosan polysulphate and polysulphated glycosaminoglycan ( PSGAG) to inhibit equine MMPs-2, and 9 were assessed by two degradatio n assays. I Whilst some agents did have direct effects on MMP activity , these effects were only obtained at concentrations which were unlike ly to be achieved for any length of time in vivo. It is improbable tha t any pharmacological agent, currently used in the horse, has a signif icant effect on gelatinase MMP activity.