Fig. 1From: Cationic amino acid transporter-1 (CAT-1) promotes fibroblast-like synoviocyte proliferation and cytokine secretion by taking up L-arginine in rheumatoid arthritisL-Arginine is upregulated in the synovial fluid of RA and is positively correlated with the elevation of cytokines. a The concentrations of amino acids in the synovial fluid of RA and OA were detected by LC–MS/MS. b The concentrations of cytokines were detected in the synovial fluid of RA and OA by CBA assay. c Pearson’s correlation analysis of the relationship between cytokines and L-arginine levels in the synovial fluid of RA patients. Data are shown as the mean ± SD from three independent experiments and each dot plot represents an individual sample. *P < 0.05Back to article page