Effect of estrogen on global myocardial ischemia-reperfusion injury in female rats.
We investigated the effects of estrogen on global myocardial ischemia-reperfusion injury in rats that were ovariectomized (Ovx), sham-operated, or ovariectomized and then given 17beta-estradiol (E(2)beta) supplementation (Ovx+E(2)beta). Hearts were excised, cannulated, perfused with and then immersed in chilled (4 degrees C) cardioplegia solution for 30 min, and then retrogradely perfused with warm (37 degrees C), oxygenated Krebs-Henseleit bicarbonate buffer for 120 min. The coronary flow rate, first derivative of left ventricular pressure, and nitrite production were all significantly lower in Ovx than in sham-operated or Ovx+E(2)beta hearts. However, coronary flow rates or nitrate production were not consistently different throughout the entire reperfusion period. Ca(2+) accumulated more in Ovx rat hearts than in sham-operated or Ovx+E(2)beta hearts, and mitochondrial respiratory function was lower in Ovx hearts than in hearts from the other two groups. Marked interstitial edema and contraction bands were seen in hematoxylin-eosin-stained sections of Ovx rat hearts but not in hearts from either of the other groups. Hematoxylin-basic fuchsin-picric acid-stained sections revealed fewer viable myocytes in hearts from the Ovx group than from the sham or Ovx+E(2)beta group. Transmission electron microscopy demonstrated more severely damaged mitochondria and ultrastructural damage to myocytes in Ovx rat hearts. Our results indicate that estrogen plays a cardioprotective role in global myocardial ischemia-reperfusion injury in female rats.
Zhai
P
P
Department of Veterinary Biosciences, University of Illinois, Urbana-Champaign, Illinois 61802, USA.
Eurell
T E
TE
Cotthaus
R
R
Jeffery
E H
EH
Bahr
J M
JM
Gross
D R
DR
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004396:Coloring Agents; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D008928:Mitochondria / Q000502:physiology; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D009206:Myocardium / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013778:Tetrazolium Salts; D013844:Thiazoles; D016277:Ventricular Function, Left / Q000187:drug effects / Q000502:physiology; D017725:Ventricular Pressure / Q000187:drug effects / Q000502:physiology
D004396:Coloring Agents; D009573:Nitrites; D013778:Tetrazolium Salts; D013844:Thiazoles; D009569:Nitric Oxide; D004958:Estradiol; C022616:thiazolyl blue; D002118:Calcium