THE MECHANISMS OF ASPIRIN-INDUCED GASTRIC-MUCOSAL INJURY

We examined changes in intracellular pH with the fluorescent probe BCE CF after treatment with aspirin (ASA) in gastric mucosal cells isolate d from guinea pigs at various extracellular, pH levels. The cytotoxic activities of ASA and the intracellular trapping of ASA at various ext racellular pH levels were also examined by colorimetric MTT assay and counting the influx of [C-14](carboxyl-C-14)-ASA. Under acid extracell ular pH, ASA reduced intracellular pH in gastric mucosal cells and exh ibited cytotoxicity. Intracellular trapping of ASA was also observed o nly under acidic extracellular conditions. The present study suggests that ASA causes gastric mucosal cell injury in vitro by reducing intra cellular pH, resulting from intracellular trapping of ASA under acidic extracellular conditions.