Reduction of RANKL and osteoprotegerin expression in FLS after incubation with AGE-BSA. (a) Receptor activator of nuclear factor kappa B ligand (RANKL) mRNA expression was significantly lower after treatment with advanced glycation end products-modified (AGE)-BSA (*P < 0.001, n = 15). (b) In addition, osteoprotegerin mRNA expression was significantly reduced by AGE-BSA (*P < 0.001, n = 8). (c) AGE-BSA reduced the release of RANKL and osteoprotegerin proteins into fibroblast-like synovial cells (FLS) supernatants compared with control-BSA (Co-BSA; *P < 0.01, n = 6). GAPDH = glyceraldehyde 3-phosphate dehydrogenase.