Rapid intracellular acidification and cell death by H2O2 and alloxan in pancreatic β cells

Abstract Pancreatic β-cell death induced by oxidative stress plays an important role in the pathogenesis of diabetes mellitus. We studied the relation between rapid intracellular acidification and cell death of pancreatic β-cell line NIT-1 cells exposed to H 2 O 2 or alloxan. Intracellular pH was measured by a pH-sensitive dye, and cell damage by double staining with Annexin-V and propidium iodide using flow cytometry. H 2 O 2 and alloxan caused a rapid fall in intracellular pH and suppressed Na + /H + exchanger activity in the NH 4 Cl prepulse method. H 2 O 2 induced necrotic cell death, which shifted to apoptotic cell death when initial acidification was prevented by pH clamping to 7.4 using nigericin (unclamped cells vs clamped cells, necrosis 43.8 ± 5.8% vs 21.1 ± 10.6%, P P 2 O 2 -treated β cells, whereas no link between cell death and acidification was demonstrated in alloxan toxicity.