Effect of aspirin on late preconditioning against myocardial stunning in conscious rabbits.
OBJECTIVE
The goal of this study was to investigate the effect of three different doses of acetylsalicylic acid (aspirin) (ASA) on the late phase of ischemic preconditioning (PC) against myocardial stunning.


BACKGROUND
Although recent evidence indicates that the late phase of ischemic PC is mediated by cyclooxygenase-2 (COX-2), the effect of nonsteroidal anti-inflammatory drugs (NSAIDs) that inhibit COX-2 activity on late PC has not been evaluated; ASA is the most widely used NSAID. Therefore, we determined whether ASA impedes the development of late PC.


METHODS
Conscious rabbits underwent a protocol consisting of three days of six 4-min coronary occlusion/4-min reperfusion cycles.


RESULTS
Neither 5 mg/kg nor 10 mg/kg x 3 of ASA interfered with the protective effects of late PC against stunning. In contrast, the late PC effect was completely abrogated by 25 mg/kg of ASA. Low-dose (5 mg/kg) ASA effectively inhibited platelet aggregation but did not prevent the increase in COX-2 activity, whereas the highest dose (25 mg/kg) completely blocked COX-2 activity.


CONCLUSIONS
The administration of ASA either at antithrombotic doses (5 mg/kg), which are widely used to prevent cardiovascular events in patients, or at analgesic/antipyretic doses (10 mg/kg) does not interfere with the cardioprotective effects of late PC against myocardial stunning. In contrast, high doses of ASA (25 mg/kg), which are used as antirheumatic therapy, abrogate both COX-2 activity and late PC, suggesting that nonselective doses of NSAIDs should be used with caution in patients with atherosclerotic cardiovascular disease because they may deprive the heart of its innate defensive response.
Shinmura
Ken
K
Experimental Research Laboratory, Division of Cardiology, University of Louisville, and the Jewish Hospital Heart and Lung Institute, Kentucky 40292, USA.
Kodani
Eitaro
E
Xuan
Yu-Ting
YT
Dawn
Buddhadeb
B
Tang
Xian-Liang
XL
Bolli
Roberto
R
D000704:Analysis of Variance; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D000911:Antibodies, Monoclonal; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D015153:Blotting, Western; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D006339:Heart Rate / Q000502:physiology; D019157:Ischemic Preconditioning, Myocardial; D007527:Isoenzymes / Q000187:drug effects*; D009203:Myocardial Infarction / Q000503:physiopathology / Q000517:prevention & control; D017682:Myocardial Stunning / Q000188:drug therapy / Q000503:physiopathology*; D010973:Platelet Adhesiveness / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects*; D011817:Rabbits; D018608:Ultrasonography, Doppler / Q000379:methods
D000894:Anti-Inflammatory Agents, Non-Steroidal; D000911:Antibodies, Monoclonal; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D001241:Aspirin