Whole grape alleviates inflammatory arthritis through inhibition of tumor necrosis factor

The anti-rheumatic efficacy of grape powder (GP) diet was evaluated in transgenic mice (TG) overexpressing human tumor necrosis factor (TNF), a model for rheumatoid arthritis (RA). After 4-weeks, TG mice fed on 10% of GP showed improvement with epiphyseal bone mass (p = 0.07) compared to TG fed on a regular diet. TG mice that received 5 or 10% of GP exhibited a significant (p < 0.05) decrease in resorption-associated osteoclasts in paw and knee joints. 10% of GP diet moderately recovered articular cartilage from TNF-mediated destruction. Both doses significantly (p < 0.05) decreased inflammation-induced formation of synovitis/enthesitis. These results correlated with the finding that 10% of GP diet downregulated TNF-mediated enhancement in transcript levels of cytokines (TNF & interleukin-1β), an osteoclastogenic factor (receptor activator of nuclear factor-κB ligand: RANKL), matrix metalloproteinases (MMP1&3), and chemokine ligand 3/macrophage inflammatory protein-1 alpha (CCL3/MIP1α). Our data suggests that the GP ameliorates RA symptoms through interfering with TNF for inflammation.