A study of Sirt1 regulation and the effect of resveratrol on synoviocyte invasion and associated joint destruction in rheumatoid arthritis

The aim of the current study was to investigate the role and mechanism of sirtuin 1 (Sirt1) in the regulation of synovial cell invasion and joint destruction in rheumatoid arthritis (RA). The Sirt1 protein and mRNA levels in fibroblast-like synoviocytes (FLS) isolated from RA synovial tissues were compared with normal tissues by western blot and reverse transcription-polymerase chain reaction. RA FLS were then treated with the Sirt1 agonist resveratrol (1, 3 and 10 mu g/ml) for 48 h, and their invasiveness and expression of matrix metalloproteinase (MMP) 1 and MMP13 protein and mRNA were measured. Furthermore, a collagen-induced arthritis (CIA) rat model was established and the rats were divided into a model group, and low- and high-dose resveratrol (2.5 and 10 mg/kg/day) groups to receive an intraperitoneal injection of resveratrol for 42 consecutive days. The joint morphology, arthritis index (AI), and MMP1 and MMP13 expression in synovial tissues was monitored. The Sirt1 protein and mRNA levels in RA FLS were significantly lower compared with normal FLS (P<0.01). The resveratrol treatment significantly inhibited the invasive ability of RA FLS (P<0.01) and reduced MMP1 and MMP13 expression (P<0.01). The AI in low- and high-dose groups was significantly lower compared with the model group from day 28 (P<0.01). Resveratrol also reduced the swelling and damage and decreased MMP1 and MMP13 expression levels in CIA rats (P<0.01). The resveratrol-induced upregulation of Sirt1 in RA FLS may significantly inhibit the invasion of these cells and reduce the degree of joint damage, which may be mediated through the inhibition of MMP1 and MMP13 expression. The present results suggested a regulatory role for Sirt1 in RA pathogenesis, and demonstrated the beneficial effects of resveratrol, which may have potential as an alternative therapeutic strategy for the treatment of patients with RA.