Peroxisome proliferator-activated receptor β/δ agonist GW0742 ameliorates cerulein- and taurocholate-induced acute pancreatitis in mice

Abstract

Background: Peroxisome proliferator-activated receptors (PPARs) are ligand activated transcription factors belonging to the nuclear receptor superfamily. PPARs activation has a profound impact on the local immune response with consequences affecting the progression of chronic inflammatory diseases. Relatively little is known on the role of PPAR-β/δ in the regulation of inflammatory responses. The aim of the present study was to evaluate the influence of PPAR-β/δ receptor in a model of edematous pancreatitis induced in mice by administration of cerulein at supramaximal doses, as well as in necrohemorrhagic model induced by intraductal administration of sodium taurocholate (STC).

Measurements: Mice were treated with cerulein (50 μg/kg) or STC (5%). GW0742 (0.3 mg/kg) was intraperitoneally administered 1 and 6 hours after cerulein injection or was injected 2 hours before STC infusion. The pancreas and exopancreatic organs were carefully removed for microscopic examination. Pancreatic weight, serum amylase, lipase, tumor necrosis factor-α and interleukin-1β levels, as well as cytokines, adhesion molecules, nitrotyrosine, poly (ADP-ribose), inducible nitric oxide, FAS ligand, Bax, Bcl-2 expression by immunohistochemistry, and myeloperoxidase activity of the pancreas were assayed. Moreover, the involvement of nuclear factor-κB pathway was investigated by Western blot analysis.

Results: Intraperitoneal injection of cerulein in mice resulted in severe, acute pancreatitis characterized by edema, neutrophil infiltration and apoptosis, and elevated serum levels of amylase and lipase. Taurocholate challenge caused a clear increase in serum amylase, neutrophil infiltration, and tissue damage in the pancreas. Tissue and inflammatory changes in the pancreata were significantly less in GW0742 group than in cerulein or STC groups. In addition, the pancreatic water content was reduced in mice treated with PPAR-β/δ agonist. In the mild pancreatitis, GW0742 was also able to decrease the expression of proinflammatory cytokines and enzymes, as well as of proteins involved in apoptosis and nuclear factor-Kappa B pathway.

Conclusion: GW0742 attenuated pancreatic damage in 2 different experimental models of pancreatitis in mice.