Fig. 2

IL-1β stimulation of NGF/NGFR expression and release in human chondrocytes. Adult human chondrocytes in culture were treated with 100 pg/ml IL-1β in growth medium (GM) consisting of DMEM with 10 % FBS. a Higher NGF gene expression in response to treatment with IL-1β (GM versus GM + IL-1β; *p <0.05), analyzed by real-time RT-PCR on day 7 of treatment, with RPL13a as housekeeping gene control. b Higher NGF secretion in culture medium in response to IL-1β treatment (GM versus NGF; *p <0.05), measured by ELISA and expressed relative to double-stranded DNA content. c Higher NGFR expression in human chondrocytes in response to IL-1β analyzed by western blotting. Ten biological cell donors were analyzed. Experiments were carried out with three technical replicates using three pooled batches of samples, with each batch consisting of five randomly chosen samples. Images were digitally scanned and values are normalized to GAPDH and day 0 GM group, and expressed as mean ± SE. Representative images from one batch experiment are shown. GAPDH protein loading control, IL interleukin, NGF nerve growth factor, p75NTR low-affinity NGFR, TrkA high-affinity NGFR