INHIBITORY EFFECT OF ALLOPURINOL ON ADJUVANT ARTHRITIS IN RATS

The effect of Allopurinol (ALLO), on adjuvant arthritis was studied in rats and compared with the effect of indomethacin (IND). Drugs were g iven by intraperitoneal injection for each day beginning from the day of adjuvant injection (day 0) and continued until the 16th day. Paw sw elling was measured on days 4, 17 and 29, and secondary lesions were a ssessed on days 17 and 29. Polymorphonuclear leukocyte (PMNs) count wa s also evaluated on day 17. ALLO, at relatively high doses (25-50 mg/k g), reduced paw swelling of the adjuvant-injected extremity on day 4; lower doses (6.25-12.5 mg/kg), however, elicited the same inhibitory e ffect on day 17. IND (0.25 mg/kg) also prevented paw swelling on days 4 and 17. Both ALLO and IND reduced the secondary lesions on days 17 a nd 29 and prevented the increase in polymorphonuclear leukocytes durin g the development of adjuvant arthritis. Possible mechanisms of the an tiinflammatory effect of ALLO in adjuvant arthritis are discussed.