Effect of phycocyanin in zymosan-induced arthritis in mice - Phycocyanin as an antiarthritic compound

The antiinflammatory effect of a phycocyanin extract was studied in zymosan -induced arthritis model in mice. Four days after the intraarticular inject ion of zymosan, (15 mg/ml), phycocyanin (25, 50, and 100 mg/kg p.o) was adm inistered to animals for 8 days. The mice were then killed and the synovial fluid measured for beta-glucuronidase. Each knee joint was totally removed for histopathological and ultrastructural studies. Phycocyanin significant ly reduced the levels of beta-glucuronidase that had been increased by zymo san. Histopathological and ultrastructural studies showed inhibition in cel lular infiltration and reduction of synovial hyperplasia and synovitis. The antiinflammatory activity exerted by phycocyanin may be due, at least in p art, to its antioxidative properties, although inhibitory effects on both a rachidonic acid metabolism and cytokine production such as tumor necrosis f actor (TNF) may also be involved. To our knowledge, this is the first repor t on the antiinflammatory effect of phycocyanin in an experimental model of arthritis. (C) 1999 Wiley-Liss, Inc.