Objective To investigate the inhibitory effect of pioglitazone on inflammatory signaling pathways induced by human pancreatitis-associated ascitic fluid (PAAF) in human monocytic cell line THP-1. Methods PAAF was collected from patients with severe acute pancreatitis. The cultured THP-1 cells were divided into 4 groups: control group (C), PAAF group (A), PPARγ agonist pioglitazone group (P), and PPARγ antagonist GW9662 group (G). Cells in group A were stimulated with PAAF, those in group P were treated with 20 μmol/L PPARγ agonist pioglitazone 2 h after stimulation with PAAF,and those in group G were treated with PPARγ antagonist GW9662, pioglitazone (30 min later) and PAAF(2 h later) in turn.After incubation for 12 h, TNF-α and IL-6 mRNA expression was measured by real-time PCR, and Western blotting analysis was used to examine the expression of the phospho-p38-mitogen-activated protein kinase (MAPK), nuclear transcription factor (NF-κB) p65 levels, and IκB. Results Compared with group C, TNF-α and IL-6 mRNA expression in group A was increased, NF-κB and p38MAPK protein levels were increased, and IκB protein level was decreased (P<0.05). Compared with group A, TNF-α and IL-6 mRNA expression was decreased in group P, NF-κB and p38MAPK protein levels were down-regulated, and IκB protein level was increased (P<0.05). Compared with group P, TNF-α and IL-6 mRNA expression was increased in group G, NF-κB and p38MAPK protein levels were increased, and IκB protein level was decreased (P<0.05). Conclusion The results show that pioglitazone can inhibit PAAF-stimulated THP-1 inflammation by blocking p38MAPK and NF-κB signaling pathway.