Interleukin-4 reversed the Interleukin-1-inhibited proteoglycan synthesis through the inhibition of NO release: a possible involvement of intracellular calcium ion.

Interleukin-1 (IL-1) causes cartilage degradation through nitric oxide (NO) synthesis. Although Interleukin-4 (IL-4) antagonizes the IL-1-mediated cartilage degradation, the precise mechanisms are not clear. We examined the effect of IL-4 on NO synthesis in parallel with intracellular Ca levels ([Ca(2+)]i) and proteoglycan (PG) synthesis.