title: Heat shock protein 90 mediates anti-apoptotic effect of diazoxide by preventing the cleavage of Bid in hypothermic preservation rat hearts.
abstract: BACKGROUND
  Successful organ preservation is the premise for clinical organ transplantation. The present study investigated whether heat shock protein 90 (Hsp90) is important in the anti-apoptotic effect of diazoxide in hypothermic preservation rat hearts.
  
  
  METHODS
  Isolated rat hearts were preserved in Celsior solution, with or without diazoxide, for 3 to 9 hours, followed by 60 minutes of reperfusion. Cell apoptosis was assessed by terminal deoxynucleotide transferase-mediated deoxy uridine triphosphate nick-end labeling. The left ventricular developed pressure (LVDP) was recorded. Expression of Hsp90 protein and cleavage of Bid were detected by Western blot and polymerase chain reaction.
  
  
  RESULTS
  After hypothermic preservation for 3 to 9 hours, the LVDP recovery rate significantly decreased and cardiomyocyte apoptosis index increased in a time-dependent manner. When compared with the 9-hour preservation group, Celsior solution supplemented with diazoxide significantly enhanced the LVDP recovery rate and decreased the apoptosis index. The cleavage of Bid increased after 9 hours of hypothermic preservation, which was inhibited by Celsior solution supplemented with diazoxide. Hypothermic preservation of rat hearts for 9 hours decreased the expression of Hsp90, whereas diazoxide supplementation significantly increased the expression of Hsp90. The Hsp90 inhibitor 17-allylamino-17-demethoxy-geldanamycin inhibited the diazoxide-induced decrease in cleavage of Bid, improvement of cardiac function, and decrease of apoptosis. Hsp90 inhibitor had no effect on the diazoxide-induced increase of total Cx43 protein expression in hearts preserved 9 hours, but inhibited the diazoxide-induced increase of mitochondrial Cx43 protein level.
  
  
  CONCLUSIONS
  Hsp90 might mediate diazoxide-induced cardioprotection against apoptosis in hypothermic preservation heart by preventing the cleavage of Bid.
authors.affiliation: Department of Pathophysiology, Zhejiang University School of Medicine, Hangzhou, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Wen-liang
authors.initials: WL
authors.lastname: Chen
authors.forename: Ming-zhi
authors.initials: MZ
authors.lastname: Zheng
authors.forename: Guo-wei
authors.initials: GW
authors.lastname: Yu
authors.forename: He-jing
authors.initials: HJ
authors.lastname: Xu
authors.forename: Yue-liang
authors.initials: YL
authors.lastname: Shen
authors.forename: Ying-ying
authors.initials: YY
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000187:drug effects / Q000378:metabolism*; D003080:Cold Temperature; D018031:Connexin 43 / Q000378:metabolism; D003981:Diazoxide / Q000494:pharmacology*; D004187:Disaccharides / Q000494:pharmacology; D004573:Electrolytes / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D005978:Glutathione / Q000494:pharmacology; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D016027:Heart Transplantation / Q000379:methods; D006639:Histidine / Q000494:pharmacology; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D008929:Mitochondria, Heart / Q000378:metabolism; D023421:Models, Animal; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D009926:Organ Preservation / Q000379:methods*; D019188:Organ Preservation Solutions / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D051023:BH3 Interacting Domain Death Agonist Protein; C494816:Bid protein, rat; C088453:Celsior; D018031:Connexin 43; D004187:Disaccharides; D004573:Electrolytes; D005971:Glutamates; D018841:HSP90 Heat-Shock Proteins; D019188:Organ Preservation Solutions; D008353:Mannitol; D006639:Histidine; D005978:Glutathione; D003981:Diazoxide