Figure 1

ROS accumulates in primary chondrocytes following mechanical stress. (a) Primary chondrocytes were isolated from ribs of 5-week-old wild-type male Wistar rats and cultured with or without cyclic loading stresses (40 g weight, 2 Hz) for 30 minutes. Cells were then stained with mouse-anti-8OHdG antibody followed by Alexa Fluor 488-conjugated goat anti-mouse IgG, treated with DAB and observed under a microscope. Bar, 100μm. (b) Primary chondrocytes similarly isolated were cultured with or without cyclic loading stresses (40 g weight, 2 Hz) in the presence or absence of NAC (10 µM) for 30 or 60 minutes and then evaluated for TNFα expression or MMP-13, respectively, by real-time PCR. Data represent mean TNFα expression or MMP-13 expression relative to β-actin ± SD (n = 3 each, *P < 0.05). Representative data of at least two independent experiments are shown.