Objectives: The anti-inflammatory effects of O-1602 and cannabidiol (CBD), the ligands of G protein-coupled receptor 55 (GPR55), on experimental acute pancreatitis (AP) were investigated.
Methods: Acute pancreatitis was induced in C57BL mice by intraperitoneal injection of 50 μg/kg cerulein hourly, with a total of 6 times. Drugs (O-1602, 10 mg/kg, or CBD, 0.5 mg/kg) were given by intraperitoneal injection 2 times at 30 minutes before the first injection and immediately before the fifth cerulein injection. At 3 hours after the last injection, the blood, the lungs, and the pancreas were harvested for the pancreatic enzyme activity, myeloperoxidase activity, and pro-inflammatory cytokines measurement; and the expressions of GPR55 mRNA and protein in the pancreas were detected.
Results: Cannabidiol or O-1602 treatment significantly improved the pathological changes of mice with AP and decreased the enzyme activities, IL-6 and tumor necrosis factor α; levels, and the myeloperoxidase activities in plasma and in the organ tissues. G protein-coupled receptor 55 mRNA and protein expressed in the pancreatic tissue, and the expressions were decreased in the mice with AP, and either CBD or O-1602 attenuated these changes to a certain extent.
Conclusion: Cannabidiol and O-1602 showed anti-inflammatory effects in mice with AP and improved the expression of GPR55 in the pancreatic tissue as well.