Expression of peroxisome proliferator-activated receptor-gamma coactivator-1 β (PGC-1β) is over-expressed in rheumatoid arthritis (RA)-fibrolast-like synoviocytes (FLS). (A) Immunofluorescence staining of PGC-1β in primary cultures of FLS from osteoarthritis (OA) and RA patients. (a, DAPI (blue); b, PGC-1β (green); c, neutral light; d, merged a, b with c. a, b, c: original magnification × 400). (B) Left panel: PGC-1β mRNA expression in FLS from RA (n = 8) compared with that from OA (n =6) evaluated by qPCR. Right panel: PGC-1β protein level in FLS from RA patients (n = 8) and OA controls (n = 6) was detected by western blot. The intensity for each band was densitometrically quantified and normalized against the intensity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The data are represented by mean ± SD. *P <0.05.