EFFECT OF AMMONIA ON CELL-CYCLE PROGRESSION OF HUMAN GASTRIC-CANCER CELLS

Aim: Ammonia is a cytotoxic factor of Helicobacter pylori that is invo lved in gastric mucosal injury. This study was designed to show whethe r ammonia has an effect on the cell-cycle progression in human gastric cells in vitro. Materials and methods: We studied the effects of ammo nia and ammonium chloride on cell growth and cell-cycle progression of the human gastric cancer cell line HGC-27. We cultured HGC-27 cells a nd counted viable cells by trypan blue dye exclusion 24 h after the ad dition of various concentrations of ammonia or ammonium chloride. DNA contents of nuclei were analysed by flow-cytometry. Results: Ammonia a nd ammonium chloride inhibited the proliferation of HGC-27 cells dose- dependently. Flow-cytometric analysis showed S-phase accumulation of H GC-27 cells treated with ammonia and ammonium chloride at cytostatic d oses. Conclusions: These results suggest that ammonia and ammonium chl oride inhibit the growth of gastric cells in S phase. This mechanism m ay make a significant contribution to the pathogenesis of Helicobacter pylori-associated gastric mucosal atrophy.