A chronic atrophic gastritis (CAG) model was established using N-methyl-N-nitro-N-nitrosoguanidine (MNNG) combined with ranitidine and irregular feeding. Briefly, mice received MNNG (150 g/mL) by gavage every other day, were fed chow containing ranitidine (0.05%), and were subjected to irregular feeding to facilitate disease progression. The total modeling period lasted 22 weeks. replicate biosample 5