Myocardial ischemia/reperfusion injury in the inducible nitric oxide synthase knockout mice.
Inducible nitric oxide synthase (iNOS) plays an important role in the inflammatory process of certain major cardiac disorders including myocardial infarction and allograft rejection. However, the role of iNOS in acute myocardial ischemia has not been well defined. We determined the effects of genetically disruption of the intact iNOS system on cardiac tolerance to ischemia/reperfusion injury. Adult male wild-type (WT) and iNOS knockout (KO) B6,129 mice were subjected to 20 min global ischemia and 30 min reperfusion in a Langendorff isolated perfused heart model (37 degrees C, n = 10/each group). Ventricular contractile function, heart rate, coronary flow, and leakage of intracellular enzymes (CK and LDH) were not significantly different between the groups during pre-ischemia as well as reperfusion period (P > 0.05). Myocardial infarct size was also not significantly different between WT (20.2+/-2.0% of risk area) and KO mice (23.5+/-3.8%; Mean+/-SEM, P > 0.05). However, the post-ischemic heart rate was significantly preserved in KO as compared to WT (P < 0.05). We conclude that disruption of iNOS gene does not exacerbate ischemia/ reperfusion injury in the heart.
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Division of Cardiology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298, USA.
Jarrett
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Hess
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Kukreja
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D000818:Animals; D003326:Coronary Circulation; D003402:Creatine Kinase / Q000378:metabolism; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009203:Myocardial Infarction / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D015428:Myocardial Reperfusion Injury / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D009206:Myocardium / Q000201:enzymology / Q000473:pathology; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D013997:Time Factors; D016276:Ventricular Function
D007770:L-Lactate Dehydrogenase; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D003402:Creatine Kinase