Rhein, an active metabolite of diacerein, suppresses the interleukin-1alpha-induced proteoglycan degradation in cultured rabbit articular chondrocytes.

Diacerein has proved to be effective in the treatment of osteoarthritis. We investigated the effects of rhein, an active metabolite of diacerein, on the degradation of recombinant human interleukin-1alpha (rhIL-1alpha)-induced proteoglycan and matrix metalloproteinases (MMPs) release from rabbit articular chondrocytes. Chondrocytes were treated for 24 h with rhein in the presence of rhIL-1alpha. Rhein suppressed the rhIL-1alpha-induced proteoglycan degradation. In addition, rhein decreased the rhIL-1alpha-induced proMMP-3 production and reduced the MMPs activity. These results suggested that diacerein might have a protective effect on proteoglycan degradation via the suppressive effect of rhein on the production of proMMPs.