Effect of polyethylene particles on the local expression of IL-1 β, IL-6, TNF-α and RANKL (ELISA). Cytokines concentrations were determined after 24 hours in culture medium by ELISA (n = 5 per group). Results are presented as mean ± standard error of the mean. a indicates P < 0.05, b indicates P < 0.005, c indicates P = 0.001, compared to internal control. IL-1 β, interleukin 1 β; IL-6, interleukin-6; TNF-α, tumor necrosis factor-α; RANKL, receptor activator of the nuclear factor κB ligand.
Nich et al. Arthritis Research & Therapy 2011 13:R100 doi:10.1186/ar3381