Abstract: AIMTo investigate the effect of meloxicam on human polymorphonuclear leukocyte (PMN) adhesion to human synovial cell (HSC), and to explore its mechanism. METHODSMTT colorimetry was used to determine the adhesion effect of PMN to HSC. Cell-ELISA and RT-PCR methods were used to determine the expression of ICAM-1 and VCAM-1. Nuclear transcription factor-kappa B (NF-κB) was measured by electrophoretic mobility shift assay (EMSA) method. RESULTS Meloxicam was found to effectively inhibit TNF-α (50 u·mL^-1 for 12 h) and IL-1β (50 u·mL^-1 for 12 h)-induced adhesion of PMN to HSC (IC₅₀ 3.38×10^-7 mol·L^-1 and 3.56×10^-6 mol·L^-1, respectively) in a concentration-dependent manner. ICAM-1 protein and mRNA expression induced by TNF-α (50 u·mL^-1) were inhibited by meloxicam at 1×10^-6～1×10^-5 mol·L^-1. The activation of NF-κB was also inhibited by meloxicam at 1×10^-6～1×10^-5 mol·L^-1. CONCLUSIONThese results suggest that meloxicam inhibit TNF-α stimulated PMN-HSC adhesion and expression of ICAM-1 by suppressing the activity of NF-κB.