Fig. 2

Concentration-dependent increase in osteopontin (OPN) production by adiponectin (AD). a Human rheumatoid arthritis synovial fibroblasts (RASFs) were incubated with AD for various doses, and OPN mRNA expression was examined after 72 h by quantitative real-time PCR (n = 3). b OPN expression in human RASFs pretreated with AD for different concentrations was determined after 72 h by immunofluorescence staining. c Human osteoarthritis synovial fibroblasts (OASFs) were incubated with AD, and OPN mRNA expression was examined after 72 h by quantitative real-time PCR (n = 3). d OPN expression in human OASFs pretreated with AD was determined after 72 h by immunofluorescence staining. OPN-positive cells were stained red (magnification ×20). Bars show the mean ± SD (*p < 0.05)