Single oral dose of geranylgeranylacetone induces heat-shock protein 72 and renders protection against ischemia/reperfusion injury in rat heart

Background-Induction of heat-shock proteins (HSPs) results in cardioprotect ion against ischemic insult. Geranylgeranylacetone (GGA), known as an antiu lcer agent, reportedly induces HSP72 in the gastric mucosa and small intest ine of rats. The present study tested the hypothesis that oral GGA would in duce HSP72 in the heart and thus render cardioprotection against ischemia/r eperfusion injury in rats. Methods and Results-Cardiac expression of HSPs was quantitatively evaluated in rats by Western blot analysis. Ten minutes of whole-body hyperthermia i nduced HSP72 expression in the rat hearts. A single oral dose of GGA (200 m g/kg) also induced expression of HSP72, which peaked at 24 hours after admi nistration. Therefore, isolated perfused heart experiments using a Langendo rff apparatus were performed 24 hours after administration of 200 mg/kg GGA (GGA group) or vehicle (control group). After a 5-minute stabilization per iod, no-flow global ischemia was given for 20, 40, or 60 minutes, followed by 30 minutes of reperfusion. During reperfusion, the functional recovery w as greater and the released creatine kinase was less in the GGA group than in the control group. Electron microscopy findings revealed that the ischem ia/reperfusion-induced damage of myocardial cells was prevented in GGA-trea ted myocytes. Conclusions-The results suggest that oral GGA is cardioprotective against i schemic insult through its induction of HSP72.