Dose effects of the ASA inhibition of MMP-9 activities released to media from THP-1 macrophages. The THP-1 macrophages were cultured in media containing 10% FBS with different concentrations of ASA for 24 h, and the activities of MMP-9 were measured by gelatin Zymography (A). Signal intensities from the zymographs were analysed by the Quantity One software and transformed to the bar graph (B). Results are expressed as mean ±S.D, of three experiments with duplicated samples. * P < 0.05,compared to control.