Modulation of murine osteoarthritis.

Up to nine out of 10 male STR/ORT mice develop osteoarthritis (OA) of the medial tibial cartilage at an early age. This has now been shown to be related to changes in the activity and distribution of monoamine oxidase which is related to the metabolism of catecholamines. Treatment with diclofenac sodium tended to normalize this activity but there was no significant histological improvement. It was therefore postulated that two influences were involved in the development of OA: a cellular and an extracellular factor. The first was improved by diclofenac sodium; the second, namely oedema of the matrix, was improved by tribenoside. In very preliminary studies, feeding the two drugs simultaneously resulted in 7/9 mice having no sign of OA.