Sodium Sulfite Causes Gastric Mucosal Cell Death by Inducing Oxidative Stress

Sulfites are commonly used as a preservative and antioxidant additives in the food industry. Sulfites are absorbed by the gastrointestinal tract and distributed essentially to all body tissues. Although sulfites have been believed to be safe food additives, some studies have shown that they exhibit adverse effects in various tissues. In this study, we examined the cytotoxic effect of sodium sulfite (NaSO) against rat gastric mucosal cells (RGM1) and further investigated its underlying molecular mechanism. We demonstrated that exposure to NaSO exerts significant cytotoxicity in RGM1 cells through induction of oxidative stress. Exposure of RGM1 cells to NaSO caused a significant formation of protein carbonyls and 8-hydroxy-2'-deoxyguanosine, major oxidative stress markers, with a concomitant accumulation of carbonylated protein-related aggregates. Furthermore, we found that incubation of lysozyme with NaSO evokes protein carbonylation and aggregation the metal ion-catalyzed free radical formation derived from NaSO. Our results suggest that NaSO might lead to gastric tissue injury induction of oxidative stress by the formation of NaSO-related free radicals.