miR-155 is overexpressed in synovial fluid mononuclear cells (SFMCs) from patients with gouty arthritis and up-regulated by stimulation with monosodium urate (MSU) crystals. (A) Samples from 10 healthy controls (HCs), and paired ones of peripheral blood and synovial fluid from 14 patients with acute gouty arthritis were obtained. (B) Freshly isolated peripheral blood mononuclear cells (PBMCs) from HCs were cultured for the indicated times in the presence of MSU crystals (100 μg/ml). Total RNA was collected from each time point. Real-time PCR analysis was performed to determine the expressions of miR-155. Results are representative of nine independent experiments. Values are shown as the mean ± standard error of the mean (SEM). *p <0.05, Mann–Whitney U-test.