Background: Many researches have been published to understand the pathogenesis and mechanism of Helicobacter pylori (Hp)-associated diseases, including gastritis followed by gastric cancer, using Mongolian gerbil (MG) model because Hp could be hardly inoculated in other animal species. The aim of this study was to evaluate the induction ability of heat shock protein (HSP70) and protective ability in the gastric mucosa of MG comparing with those of Sprague-Dawley (SID) rats, since HSP70 is a key molecule known to be involved in important biological activities such as apoptosis, carcinogenesis, and cytoprotection from cytotoxic damage. Materials and methods: Basal expression level and induction ability of gastric mucosal HSP70 were evaluated by immunoblotting and densitometric analysis in MG and SID rats before and after HSP-induction by zinc L-carnosine, gastric HSP70 inducer, administration. Mucosal protective ability against water-immersion stress-induced mucosal lesion was also compared. Results: Basal expression level of HSP70 was not significantly different between MG and SID rats. However, HSP70-induction by zinc derivatives was not observed in MG. Mucosal lesion induced by water-immersion stress was significantly severe in MG compared with SID rats. Conclusions: MG might be special (not ordinary) animal, in which HSP70-induction was absent and has extremely poor mucosal protective ability in view of HSP-dependent cytoprotection in the gastric mucosa. Our results may suggest that MG is not an adequate animal to evaluate the effect of Hp-infection-associated gastric inflammation followed by development of gastric cancer. (c) 2006 Elsevier Inc. All rights reserved.