In addition, qRT-PCR was performed to compare some common fibroblast markers in OA FLS and RA FLS (Fig. 1e), including Prolyl-4-hydroxylase (P-4-H), Vimentin, procollagen I (COL1A1) and procollagen III (COL3A1). This evidence concerns the gene COL3A1 and rheumatoid arthritis.