Abstract
Osteoarthritis is an inflammatory disease of load-bearing synovial joints that is currently treated with drugs that exhibit numerous side effects and are only temporarily effective on pain, the main symptom of the disease. Consequently, there is an acute need for novel, safe and more effective chemotherapeutic agents for the treatment of osteoarthritis and related arthritic diseases. Resveratrol is a phytoalexin stilbene produced naturally by plants including red grapes, peanuts and various berries. Recent research in various cell models has demonstrated that resveratrol is safe and has potent anti-inflammatory properties. However, its potential for treating arthritic conditions has not been explored. In this study we provide experimental evidence that resveratrol inhibits the expression of VEGF, MMP-3, MMP-9 and COX-2 in human articular chondrocytes stimulated with the pro-inflammatory cytokine IL-1beta. Since these gene products are regulated by the transcription factor NF-kappaB, we investigated the effects of resveratrol on IL-1beta-induced NF-kappaB signaling pathway. Resveratrol, like N-Ac-Leu-Leu-norleucinal (ALLN) suppressed IL-1beta-induced proteasome function and the degradation of IkappaBalpha (an inhibitor of NF-kappaB) without affecting IkappaBalpha kinase activation, IkappaBalpha-phosphorylation or IkappaBalpha-ubiquitination which suppressed nuclear translocation of the p65 subunit of NF-kappaB and its phosphorylation. Furthermore, we observed that resveratrol as well as ALLN inhibited IL-1beta-induced apoptosis, caspase-3 activation and PARP cleavage in human articular chondrocytes. In summary, our results suggest that resveratrol suppresses apoptosis and inflammatory signaling through its actions on the NF-kappaB pathway in human chondrocytes. We propose that resveratrol should be explored further for the prophylactic treatment of osteoarthritis in humans and companion animals.