The major heat shock protein, HSP70, is known to be involved in cytoprotection against environmental stresses mediated by their function as a "molecular chaperone." However, the influence of HSP70 on gastric mucosal healing under physical stimulation or stress is not completely understood. Rat gastric mucosal cells (RGM-1) were stably transfected with pBK-CMV containing the human HSP70 gene (7018-RGM-1) or pBK-CMV alone (pBK-CMV-12). Artificial wounds were created. Mechanical stretch was applied to 7018-RGM-1 cells or pBK-CMV-12 cells. The effect of mechanical stretch on HSP70 expression was assessed by Western blot analysis. Expression of HSP70 was decreased by mechanical stretch in pBK-CMV-12 cells. However, expression of HSP70 was not decreased by mechanical stretch in 7018-RGM-1 cells. Furthermore, the wound restoration of pBK-CMV-12 cells was suppressed under mechanical stretch condition. On the other hand, the wound restoration of 7018-RGM-1 cells was not affected by mechanical stretch. These results suggest that HSP70 plays an important role in gastric wound healing under physical stress.