Over-expression of inducible heat shock protein 70 in the gastric mucosa of partially sleep-deprived rats

Background: Previous findings have demonstrated increased expression of inducible heat shock protein 70 ( iHSP70) in the gastric mucosa of rats exposed to partial sleep deprived ( PSD). The purpose of this study was to investigate the functional role of iHSP70 and its relationship with acid secretion in the stomachs of PSD animals. Methods: A slowly rotating drum was used to induce PSD in male Sprague-Dawley rats with or without omeprazole treatment. Gastric mucosal samples were harvested for iHSP70 mRNA and protein analysis with RT- PCR and Western blotting, respectively. Enzyme immunoassay was used to determine plasma gastrin level and gastric acidity was measured by titration. The modulating effect of PSD on 0.6M hydrochloric acid ( HCl)- induced gastric damage was also evaluated. Results: PSD increased plasma gastrin, gastric acidity and expression of iHSP70, while significantly reducing HCl- induced gastric damage. Omeprazole administration decreased gastric acidity and reversed iHSP70 over- expression in PSD rats. Conclusions: PSD increases gastric acidity which enhances expression of mucosal iHSP70. Over- expression of iHSP70 may be a protective homeostatic response of the stomach to stress induced by PSD and acid secretion.