Comparative study between steroidal and nonsteroidal anti-inflammatory drugs on the mode of their actions on vascular permeability in rat carrageenin-air-pouch inflammation.

Abstract

To clarify mechanisms of antiinflammatory actions of steroidal and nonsteroidal antiinflammatory drugs with special reference to the possible role of E type prostaglandins [PG] in the inflammatory process, modes of action of the drugs were investigated by using the acute exudative stage and chronic proliferative stage of carrageenin-air-pouch inflammation in rats. This inflammation was induced on the backs of rats by s.c. injection with air and carrageenin solution. Plasma exudation in the inflammation locus was determined with the aid of radioiodinated serum albumin. In the acute exudative stage of this inflammation, a single oral administration of dexamethasone, indomethacin, phenylbutazone or aspirin all exerted a potent anti-exudative effect, while in the chronic proliferative stage only dexamethasone was effective in inhibiting the exudation of the labeled albumin. PGE level in the exudate of the acute stage inflammation was suppressed by dexamethasone or indomethacin in accordance with the inhibition of vascular permeability. PGE is important in the acute exudative inflammation. Steroidal and nonsteroidal anti-inflammatory drugs have similar mechanisms, of anti-exudative action in the acute inflammation. The exudative-process in the chronic proliferative inflammation is independent of PG. The role of extra-PG mechanism(s) for the anti-exudative action of anti-inflammatory steroids is discussed.