Time-course of oxygen free radical production in acinar cells during acute pancreatitis induced by pancreatic duct obstruction

The time-course of oxygen free radicals (OFR) generation within acinar cells was studied at different stages of acute pancreatitis (AP) induced in rats by duct obstruction (PDO) for 48 h by flow cytometry, using dihydrorhodamine-123 (DHR) as fluorescent dye. Parallel measurements of the most common markers of oxidative stress such as glutathione (GSH) depletion and malondialdehyde (MDA) levels in pancreas were also performed. OFR production significantly increased within acinar cells at early stages of AP, concomitant with a marked depletion in pancreatic GSH. Lipid peroxidation was significantly enhanced 6 h after PDO, suggesting that the antioxidant defence system of the cell is overwhelmed by OFR production. Both MDA and OFR production in acinar cells decreased to normal values at late AP stages, thus allowing the recovery of pancreatic GSH levels 48 h after PDO. Among the two types of acinar cells differentiated by flow cytometry, R1 and R2, it was the R2 population that showed higher values of DHR dye. However, no differences between the two cell types were found regarding the amount of OFR generation. Our results demonstrate that individual acinar cells significantly contribute to produce large amounts of OFR at early stages of AP. The two existing populations of acinar cells displayed similar behaviour regarding oxidative stress over the course of the disease.