The effect of trichostatin A (TSA) on gene expression in lipopolysaccharide (LPS) -treated macrophages. Mouse peritoneal macrophages were transfected with the miR-301a inhibitor and its control. After overnight incubation, macrophages were treated with TSA for 48 hr, and then treated with media or LPS for 6 hr. The mRNA levels of miR-301a (a), nuclear factor-κB (NF-κB) repressing factor (NKRF) (b), cytochrome oxidase 2 (COX-2) (d) and interleukin-6 (IL-6) (e) were detected by quantitative PCR. The protein levels of NKRF (c), COX-2 and phosphorylated (p-) IκBα (f) were determined by Western blot. Data are presented as the mean ± SD (n = 3) of three independent experiments. *P < 0·05 and **P < 0·01 compared with neither LPS nor TSA stimulation; ##, P < 0·01 compared with LPS but without TSA stimulation; &&, P < 0·01 compared with both LPS and TSA stimulation.