Figure 1

Expression of Toll-like receptors in synovium from Dark Agouti rats with pristane-induced arthritis. (A) Expression of TLR1 through TLR9 at D0, D6, D12 and D26, and (B) expression of IFN-β and IL-6 at D0 and D26 in synovium from rats (n = 8 to 10 for each time point) after pristane injection were measured by performing real-time PCR. Relative mRNA expression was compared with β-actin. Values shown are means ± SEM. Levels of significance between the pristane treatment group (D6, D12 and D26) and the control group (D0) were calculated by using Student's t-test (*P < 0.05, **P < 0.01). (C) TLR3 protein was assessed by performing immunohistochemistry in pristane-induced arthritis (PIA) synovium. TLR3 was strongly stained (brown, left-hand image) in synovium, especially in fibroblast-like synoviocytes (FLSs) (inset). FLSs from PIA joints expressed TLR3 predominantly at sites of attachment and invasion into cartilage and bone (open arrowheads). Staining specificity was assessed using isotype-matched antibodies as negative controls (right-hand image). Scale bars, 100 μm.