In order to find new drugs to inhibit nitric oxide (NO) production, the effects of pyrrolidine dithiocarbamate (PDTC), a nuclear factor-kappa B (NF-kappaB) inhibitor, on recombinant human interleukin-1beta (rhIL-1beta)-induced NO production in chondrocytes were investigated. Rat chondrocytes were isolated and cultured, divided into control, P0, P1, P2, P3 and P4 groups. The chondrocytes in the P0, P1, P2, P3 and P4 groups were treated with different concentrations of PDTC (0, 3, 10, 30, and 50 micromol/L respectively) for 1 h and then incubated with 5 U/mL rhIL-1beta for 24 h. NO assay kit and RT-PCR were used to detect the NO content and the iNOS mRNA expression in the chondrocytes. The expression level of iNOS mRNA in control, P0, P1, P2, P3 and P4 groups was 0.02+/-0.01, 1.24+/-0.13, 1.21+/-0.14, 0.61+/-0.11, 0.40+/-0.09, 0.21+/-0.06, and the relative content of NO was 15.8+/-2.7, 100+/-14.8, 92.6+/-9.3, 68.3+/-14.2, 27.5+/-9.8, 19.8+/-3.6, respectively. In the P0, P1, P2, P3 and P4 groups, the expression of iNOS mRNA and NO production were significantly increased as compared with those in the control group. As compared with the P0 group, the expression of iNOS mRNA and NO content in control group were lower. In the P2, P3 and P4 groups, PDTC could significantly inhibit the expression of iNOS and NO production induced by rhIL-1beta in a concentration-dependent manner. It is suggested that PDTC can inhibit NO production and iNOS mRNA expression induced by IL-1beta, which may provide an alternative method for the treatment of osteoarthritis.