Fig. 1

Differential expression of Toll-like receptor (TLR) family members in normal and osteoarthritic (OA) cartilage and fibronectin fragment (FN-f)-regulated TLR-2 expression in human chondrocytes. a Expression of the TLR-1–TLR-5 genes in normal and OA cartilage was determined using SYBR Green-based real-time polymerase chain reaction. The expression level of TLR family members was normalized to that of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Cycle threshold changes (ΔC _t) were calculated by subtracting C _t values of GAPDH from C _t values of TLR family members. The mean value of gene expression level in normal cartilage was designated as 1 in each experiment. Also, the expression levels of TLR family members were described as raw C _t values. Data represent the mean ± SD for duplicate experiments from ten separate donors. Lines within the boxes represent the median, boxes represent the 25th and 75th percentiles, and lines outside the boxes correspond to the minimum and maximum values. b TLR-2 mRNA expression levels in OA chondrocytes were measured at 6, 12, and 24 h after treatment with intact FN or various FN-fs. The expression level of TLR-2 was described as raw C _t values as well as relative values, normalized to that of GAPDH. Data represent the mean ± SD for triplicate experiments from three different donors (n = 3). *P < 0.05, **P < 0.01, and ***P < 0.001 vs. control