PRELIMINARY-OBSERVATIONS ON THE EFFECTS OF MELOXICAM IN A NEW MODEL FOR ACUTE INTRAARTICULAR INFLAMMATION IN DOGS

The effects of intra-articular injection, on two occasions, 3 weeks ap art, of the contrast agent Urografin on the cytological and biochemica l characteristics of synovial fluid (SF) Were examined in two studies in dogs. The first study provided baseline data in two non-medicated d ogs. The second study used a cross-over design whereby 4 dogs received a 7-day oral treatment with either a placebo or meloxicam (0.2 mg/kg body weight daily) with a washout period of 3 weeks, in order to deter mine the effect of this new non-steroidal anti-inflammatory drug (NSAI D) on the response to Urografin injection. SF samples were collected u nder general anaesthesia prior to and at 24 and 72 h after each Urogra fin injection. The volume, relative viscosity, white blood cell count and concentrations of protein, lactate dehydrogenase (LDH and hyaluron ic acid of these samples were determined. The results from both studie s indicate that intra-articular injection of Urografin provoked a mild local transient inflammatory response, the most dramatic evidence of which was an increase in the white blood cell count in the SF after 24 h. In the second study, comparison of the synovial fluid measurements of the placebo-treated dogs at 24 h after Oragrafin injection with th ose prior to injection revealed significant increases in SF volume, wh ite blood cell count, protein concentration and LDH activity and a sig nificant reduction in relative viscosity. At 72 h after injection, onl y the white blood cell count and relative viscosity were significantly different from the pre-injection values. All of these measurements we re, however, associated with high coefficients of variation, which mus t be taken into account in assessing the usefulness of the model for d rug-testing purposes. Nevertheless, the administration of meloxicam si gnificantly reduced the SF volume and white blood cell count at 24 h r elative to the effects of concurrent placebo treatment. The general he alth status of the animals was not disturbed at any time as assessed b y clinical and haematological observations. No adverse reactions were observed.