Abstract
In total joint replacement, particle induced inflammatory reactions cause periprosthetic bone resorption. Using an air pouch model in rats, we investigated the inflammatory reaction by alumina and polyethylene particles, and also investigated the anti-inflammatory effects of indometacin farnesil (IMF) . Irrigation fluid from the air pouch was collected and the total protein (TP) concentration and the prostaglandin E2 (PG E2) level were measured. To eliminate the effects of dilution, PG E2/TP was used. The pouch tissue was histologically evaluated. Without IMF, PG E2/TP was significantly higher by injecting alumina and polyethylene particles. In the polyethylene particles injected group, the level diminished with IMF 3 mg/kg/day, and was significantly lower with IMF 10 mg/kg/day. On the other hand, the level was not affected by IMF administration in the alumina particle injected group. A similar tendency was observed in the histology of pouch tissues. These results indicated that both alumina and polyethylene particles induced inflammatory reactions, however the anti-inflammatory effects of IMF depended on the characteristics of the particles.
