P2X7R Blockade Prevents NLRP3 Inflammasome Activation and Pancreatic Fibrosis in a Mouse Model of Chronic Pancreatitis

Objectives The aim of this study was to investigate the role of P2X7R (purinergic 2X7 receptor) and NLRP3 (NACHT, LRR, and PYD domains–containing protein 3) inflammasome activation in the process of pancreatic fibrosis in a mouse model of chronic pancreatitis (CP). Methods Chronic pancreatitis was induced by repeated intraperitoneal injections of 50 μg/kg cerulein for 6 weeks in mice. P2X7R antagonist oxidized ATP (OxATP) or brilliant blue G (BBG) was administered after the last cerulein injection for 2 weeks. Pancreatic chronic inflammation and fibrosis were evaluated by histological score, Sirius red staining, and alpha-smooth muscle actin immunohistochemical staining. We further determined pancreatic P2X7R, NLRP3, and caspase-1 expressions in gene and protein levels and the pancreatic concentrations of caspase-1, interleukin 1β (IL-1β), and IL-18. Results The pancreatic P2X7R, NLRP3, and caspase-1 expressions in gene and protein levels and the pancreatic concentrations of caspase-1, IL-1β, and IL-18 were all reduced significantly in both the OxATP and BBG groups ( P < 0.05). The pancreatic chronic inflammation and the fibrosis indices were all remarkably attenuated ( P < 0.05). Conclusions P2X7R antagonist OxATP and BBG significantly decreased pancreatic chronic inflammation and fibrosis in a mouse CP model and suggested that blockade of P2X7R-NLRP3 inflammasome signaling pathway may represent a novel therapeutic strategy for CP and its fibrotic process.