Anti-inflammatory properties of zinc protoporphyrin disodium (Zn-PP-2Na)

Anti-inflammatory properties of zinc protoporphyrin disodium (Zn-PP-2Na) were studied. Zn-PP-2Na exhibits anti-allergic action against type III and IV reactions (passive Arthus reaction in rats and tuberculin-induced footpad reaction in mice), but does not affect type I and II reactions (homologous passive cutaneous anaphylaxis in mice and reversed cutaneous anaphylaxis in rats). Zn-PP-2Na also clearly inhibits type II collagen-induced arthritis in mice. The agent inhibits general arthritis symptoms, anti-type-II collagen antibody production and type II collagen-induced delayed type hypersensitivity (DTH) in arthritic mice. Zn-PP-2Na, however, did not affect carrageenin-induced paw edema and histamine- and serotonin-induced skin reactions in rats. Zn-PP-2Na inhibits IL-1-induced mouse lymphocyte proliferation, but does not affect PMA-induced O2- generation from guinea-pig neutrophil. These results indicate that Zn-PP-2Na inhibits type II collagen-induced arthritis in mice due to the antagonism of IL-1 activity and the inhibition of DTH against type II collagen.