The anti-inflammatory effect of glucocorticoid-induced phospholipase inhibitory proteins

The anti-inflammatory effect of glucocorticoids has been investigated in two standard models of experimental inflammation, i.e. rat paw oedema induced by carrageenin or dextran. Both types of oedema are suppressed by dexamethasone while indomethacin and BW755C only suppress carrageenin oedema. Dexamethasone inhibits dextran oedema according to the accepted mode of action of steroid hormones since the inhibition occurs after a 2-3 h time lag and is abolished by pretreating animals with actinomycin D. Dextran oedema and carrageenin oedema are also controlled by endogenous corticoids since adrenalectomy potentiates the paw oedema formation induced by low concentrations of phlogogenic agents. It has been shown that glucocorticoids induce both in vitro and in vivo the formation and release of antiphospholipase proteins which are anti-inflammatory in that they greatly suppress carrageenin oedema. However, these proteins have no effect on dextran oedema. We conclude that the inhibition of dextran oedema by glucocorticoids depends on the formation of another type of anti-inflammatory protein.