| Coronary heart disease (CHD) has become a great threat to mankind health since long term. The major complications were myocardial infarction (MI) and suddenly cardiac death (SCD). Clinical data demonstrated that intra-blood plasma catecholamine (CA) increased transiently after occurrence of myocardial infarction, norepinephrine (NE) distributed disproportional but also sympathetic adrenamine displayed variously degree exhausted in the infracted and non-infracted region with the isolated myocardial infarction model of rats. Injuring of sympathetic nerve during the process of myocardial infarction would lead to the obstruction of cardiac sympathetic nerve neuron synapse signal conduction and was more likely to cause arrhythmia, heart failure or SCD.This study was performed to investigate whether the cardiac sympathetic nerve neuron injuring was more sensitive than myocardium injuring as the parameter of myocardium infarction, and try to elucidate reperfusion protection sympathetic nerve neuron and myocardium from injuring by myocardial infarctionmodel of rabbits in vivo through the way of dual tracer autoradiography with 131I-MIBG and 99mTc-MIBI. Combined with methylene blue (MB) and triphenyl tetrazolium chloride (TTC) staining.13N-NH3 myocardial perfusion under PET imaging was used to compare infracted areas with 131I-MIBG and 99mTc-MIBI autoradiography in subacute myocardial infarction group animals.1 Methods:1.1 Animal modelThe method for the ischaemia-reperfusion model of has been reported by Fukuchi K et al. Briefly, after an overnight fast, Male New Zealand white rabbits (3.2 +3.4 kg) were anaesthetized with sodium pentobarbital (30 mg/kg) administered via a marginal ear vein. Under sterile a left thoracotomy was performed in the 5th intercostals space, and excising the pericardium exposed the heart. A 5-0 silk suture on a small curved needle was passed through the LAD artery. A small vinyl tube was passed into both ends of the suture to make the snare.According to our test aims, 24 male rabbits randomly divided into acute (n=12) and subacute (n=12) myocardial infarction groups. Acute groups including non-reperfusion (n = 6), the left anterior descending (LAD) artery was directly ligated, but for the acute reperfusion group (n =6), the LAD artery ligated 45 min subsequently re-open 2 h form reperfusion. In subacute groups, also including non-reperfusion (n = 6) directly ligated the LAD artery and reperfusion (n = 6), the LAD artery ligated 45 min subsequently reopen. Incisions were closed in subacute groups, and sterile dressings were applied. The animals were allowed to recover, and a prophylactic antibiotic was given twice a day for 2 days andmono cage breeding. One week later, those rabbits overnight fasting were anaesthetized with sodium pentobarbital (30 mg/kg), the operated methods as the same with acute groups. For subacute reperfusion group, the LAD artery was religated 45 min subsequently reopen 2 h then performed reperfusion.1.2 Positron Emission Tomography Studies procedureAfter the animals were supine positioned on the LS-PET/CT table for subacute groups animals, Myocardial blood flows imaging were obtained 148 MBq (4 mCi) 13N-ammonia administered via a marginal ear vein over 20 s. According to PET imaging procedure, PET/CT acquisition of dynamic scans began 5 min after injection and was accomplished within 10 min.1.3 Ex vivo dual isotopes autoradiographic Studies procedureFor all of groups, when the ligated artery were re-opened 2 h or ligated 2 h 45 min. 14.8 MBq (0.4 mCi) of 131I-MIBG were administered via a marginal ear vein with, 2 h after 131I-MIBG injection; the rabbits were intravenously with 185 MBq (5.0 mCi) of 99mTc- MIBI. 15 min 99mTc-MIBI after injection, the left coronary artery was religated and 2.0 ml 2% methylene blue dye was directly injected into rabbits left ventricle. Then the rabbits were killed by intravenous 10ml with 100g/L-saturated KC1 after reperfusion. And their hearts were quickly excised small tissue blocks for Transmission elec...
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