Insulin-like growth factors counteract the effect of interleukin 1 beta on type II phospholipase A2 expression and arachidonic acid release by rabbit articular chondrocytes.

ABSTRACT

Interleukin 1 beta was found to stimulate arachidonic acid release, and the synthesis and secretion of type II phospholipase A2 by rabbit articular chondrocytes in vitro. Interleukin 1 beta had no effect on the level of cytosolic phospholipase A2 mRNA. Insulin-like growth factors, which help stabilize the cartilage matrix, reduced the effect of interleukin 1 beta on type II phospholipase A2 activity and mRNA level, and decreased the Interleukin 1 beta-stimulated arachidonic acid release to the basal values. This suggests that type II phospholipase A2 plays a key role in arachidonic acid release from rabbit articular chondrocytes and that insulin-like growth factors counteract the effect of interleukin 1 beta. They may therefore be considered as potential antiinflammatory agents.