| Objective To observe the effects of Naloxone (Naloxone , NAL) on ischemia reperfusion hemodynamics, arrhythmias, myocardial ultrastructure, myocardial infarct size, myocardial apoptosis, and discuss its mechanism.Methods 36 Healthy male SD rats weighing 250~350g, with left anterior descending coronary artery ligation were prepared myocardial ischemia reperfusion model. All rats were randomly divided into 4 groups (n=9), blank control group (Con group) threading, but not ligate left anterior descending coronary artery;Ischemia reperfusion group (I/R group) ischemia and 30min, reperfusion 90min; ischemic preconditioning group (IPC group) ischemia and 5min, reperfusion 5min, repeated 3 times, after the same as I/R group;Naloxone pretreatment group (Nal+I/R group) 5 min before the ligation,on the jugular vein inject with naloxone injection with 3mg/kg, after the same as I/R group. Recorded before and after ischemia-reperfusion hemodynamic parameters at different time points,monitor the incidence of arrhythmia and make scores, observe myocardial ultrastructural changes by light microscopy, TTC staining of myocardial infarct size, apoptosis by TUNEL assay and calculated apoptotic index.Results To observe HR, MAP index at different time points, the difference was not statistical significance (P>0.05), between different treatment factors in HR, MAP indexes, the differences were not statistical significances too (P>0.05), and between treatment and time factors there were no interaction, both had no effect on HR, MAP index change (P>0.05); and LVSP,±dp/dtmax and LVEDP indexes at different time points have statistically significant differences (P<0.05), different treatment factors between the LVSP,±dp/dtmax and LVEDP indexes had statistically significant differences (P<0.05), and treatment factors and time there were interaction, both may jointly affect changes of LVSP,±dp/dtmax and LVEDP indexes (P<0.05); but compare IPC group with the Nal+I/R group, the changes of LVSP,±dp/dtmax and LVEDP indexes have no significant differences (P>0.05). Compare I/R group, with IPC group and the Nal+I/R group, arrhythmia scores, myocardial infarct size and apoptosis indexes were significantly lower, the differences had statistically significant (P<0.05). Observe microscope myocardial ultrastructure of IPC group and Nal+I/R group under light, the degree of myocardial degeneration and necrosis tissue and the degree of muscle fibers, cells, stromal swelling compared with I/R group was significantly reduced.Conclusions Naloxone is effective in improving ischemia-reperfusion hemodynamic effects in rats and reduces the incidence of arrhythmia, reduces myocardial tissue necrosis, reduces infarct size, reduces apoptosis index. Naloxone has protective effect on myocardial ischemia-reperfusion. |
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