Do antioxidant vitamins reduce infarct size following acute myocardial ischemia/reperfusion?
There is controversy concerning the ability of antioxidant vitamins to reduce myocardial infarct size. We sought to determine whether a brief prophylactic treatment of vitamin C or vitamin C plus Trolox (a water-soluble form of vitamin E) could reduce myocardial infarct size in an experimental model. We used an anesthetized open-chest rabbit model in which a branch of the circumflex coronary artery was ligated for 30 minutes followed by 4 hours of reperfusion. Experiments were performed in a randomized and blinded fashion. An IV injection of normal saline pH balanced to 7.4 (control group n = 15), vitamin C (150 mg/kg, n = 14), or vitamin C plus Trolox (150 mg/kg plus 100 mg/kg, respectively, n = 15) was administered prior to coronary occlusion. Collateral blood flow during coronary occlusion was measured by radioactive microspheres, myocardial risk zone (AR) was assessed by blue dye injection, and myocardial infarct size (AN) was assessed by triphenyltetrazolium chloride staining. All rabbits received comparable ischemic insult: Collateral blood flow and AR were similar among all three groups. Infarct size, measured as a percent of AR, did not differ significantly among the controls (21%), vitamin C (29%), or the vitamin C plus Trolox (18%) groups. Therefore, in this ischemia/reperfusion model, antioxidant vitamins did not alter myocardial infarct size.
Bellows
S D
SD
Heart Institute, Hospital of the Good Samaritan, Los Angeles, CA 90017-2395, USA.
Hale
S L
SL
Simkhovich
B Z
BZ
Kay
G L
GL
Kloner
R A
RA
D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002839:Chromans / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D006339:Heart Rate / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy*; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000503:physiopathology; D011817:Rabbits; D011897:Random Allocation; D013194:Staining and Labeling; D013778:Tetrazolium Salts / Q000737:chemistry / Q000378:metabolism; D014810:Vitamin E / Q000031:analogs & derivatives
D000975:Antioxidants; D002839:Chromans; D016166:Free Radical Scavengers; D013778:Tetrazolium Salts; D014810:Vitamin E; C009591:triphenyltetrazolium; D001205:Ascorbic Acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid