Xanthine oxidase-mediated intracellular oxidative stress in response to cerulein in rat pancreatic acinar cells

Intralobular oxygen radical formation was examined in cerulein-stimulated rat pancreatic acinar cells by digital imaging microscopic fluorography using a hy-droperoxide-sensitive fluorescent probe, dichlorofluores-cin (DCFH) diacetate. The isolated pancreatic acinar cells loaded with DCFH diacetate were microscopically observed, and the dichlorofluorescein (DCF) fluorescence yielded by DCFH oxidation via hydroperoxides was digitally processed. Within the initial 20 min after the application of cerulein (10 μM), intracellular oxidative stress was observed as indicated by the increase in DCF fluorescence intensity and reached its maximum at 60 min. DCF fluorescence intensity was then gradually decreased until 80 min, followed by a marked increase in propidium iodide (PI) fluorescence, suggesting irreversible cell death. Allopurinol (1 μM), a xanthine oxidase inhibitor, significantly attenuated the early increase of DCF fluorescence intensity as well as the late cell damage. Treatment with hyperbaric oxygen (PO₂300 mm Hg) also significantly attenuated both the increase of DCF fluorescence and the number of Pl-positive cells. The results suggest that xanthine oxidase-mediated oxygen radicals may play an important role in cerulein-induced intracellular oxidative stress in pancreatic acinar cells of rats.