Induction of a 72-kDa heat-shock protein in cultured rat gastric mucosal cells and rat gastric mucosa by zinc L-carnosine

An antiulcer drug, zinc L-carnosine (polaprezinc), provides gastric mucosal protection against various irritants. In this study, we evaluated the effects of zinc L-carnosine on expression of 72-kDa heat shock protein (HSP72, stress inducible HSP70), which is known as an endogenous cytoprotectant in a wide variety of cells, including rat gastric mucosa in vitro and in vivo. Expression of HSP72 after exposure to zinc L-carnosine, zinc sulfate, or L-carnosine (1-300 microM) in rat gastric mucosal cells (RGM1) and intragastric administration of zinc L-carnosine, zinc sulfate (30 or 100 mg/kg) and L-carnosine (76 mg/kg) was investigated by western blotting and densitometric analysis. Exposure to zinc L-carnosine and zinc sulfate increased the expression of HSP72 significantly in RGM1 cells. Intragastric administration of zinc L-carnosine and zinc sulfate showed significant increment in HSP72 in rat gastric mucosa also in vivo. The ability to induce HSP72 is significantly higher in zinc L-carnosine compared with zinc sulfate based on molecular concentration in vivo. However, L-carnosine did not increase the expression of HSP72 in vitro and in vivo. Zinc derivatives, especially zinc L-carnosine, could be a strong HSP72 (chaperon) inducer, which has been known to enhance mucosal protective ability.