Objective To investigate the effects of different duration of myocardialischemia on reperfusion -induced arrhythmias and cardiac performance、 MDA 、 SOD 、 morphological in rat hearts in vivo. Method Adult Wistar rat...
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Objective To investigate the effects of different duration of myocardialischemia on reperfusion -induced arrhythmias and cardiac performance、 MDA 、 SOD 、 morphological in rat hearts in vivo. Method Adult Wistar rats were randomly dividedinto six groups. The left anterior coronary descending branch was ligated in 0,5, 10,15,30min and 1 hour respectively following 45min of reperfusion. The ECG were recorded incessantly. LVSP and ± LVdp/dtmax of pre-ischemia、post-ischemia and 45min reperfusion were recorded. Myocardial tissue of infarc-ted zone was scissor tomeasure malondialdehyde ( MDA ) content and superoxidedismutase ( SOD ) content. The reperfused myocardial morphology were observed. Result The occurrence rate of reperfusion arrhythmias was 100% after 10min ischemia and 45min reperfusion, the occurrence rate was declined whether the ischemia duration shorter or longer, none of reperfusion arrhythmia occur after 1 hour occlusion of coronary artery in rat. LVSP, ± LVdp/dtmax 、 SOD were decreased along with the ischemic duration prolonged, on the contrary MDA was increased. Microscopy revealed stunned - myocardial tissuestructure was normal after 5 - 15min ischemia following 45min reperfusion, 30min myocardial ischemia induced slice or stove range of necrosis of cell, farthermore,1h myocardial ischemia induced obviously necrosis. Conclusion The degree of reperfusion arrhythmias will be more severity alonged with the prolonging of ischemia duration in a limit time, after a peak time it is abated and over a limited time reperfusion arrhythmias do not occur. Free oxygen radicals are not the most important to reperfusion arrhythmi-a. Cardiac performance, free oxygen radicals are decreased along with the myocardial ischemic duration. Early reperfusion can attenuate the degree of myocardial stuning.
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