| Objectives: This study aimed to observe the effects and the mechanismsof amiodarone on NR in rabbits myocardial ischemia/reperfusion no-reflowmodel:①By detecting SOD activity, MDA content and no-reflow range, fromthe viewpoints of oxygen free radicals on the no-reflow protective effect ofamiodarone;②By detecting apoptotic rate, apoptosis-related genes Bcl-2, Bax proteinexpression and no-reflow range, from the viewpoints of apoptosis ofamiodarone on no-reflow protection.Methods: Experimental model preparation and detection processes:Atotal of60New Zealand white rabbits(2.5±0.3kg;age of11-12weeeksold.)were used for this study(Laboratory Animal center in HeBei MedicalUniversity).The animals were randomized into three groups:①sham group,where the animals received left thoracotomy without ligation to leftcircumflex artery(LCX) and were left for210min(n=20);②ischemia/reperfusion group(I/R),where the LCX was occluded by ligation for90min and the ligation was removed to allow reperfusion for120min,followed by intravenous injection of the same amount of5%glucose(n=20);③amiodarane group(AM),where the LCX was occluded byligation for90min,followed by intravenous injection of amiodarane at3mg/kgfrom the time of ligation removed throughout reperfusion(n=20).After120minutes reperfusion,the level of serum SOD and MDA were measured;theprotein expression of Bcl-2and Bax was studied by immunohistochemicalstaining,and the ratios of Bcl-2/Bax were calculated;apoptosis rate wasdetermined with flow cytometer;the ischemia risk area and the no-reflow(NR)area were determined by Evans blue and Thioflavine Srespectively. Statistical analysis:Statistical analysis was carried out by usingthe SPSS13.5software.All data are expressed as the arithmetic mean±SEM.Statistical Significance was determined using ANOVA followed by Student’st-tests.q-test was used to compare between groups (Newman-Keuls),A P value<0.05was considered to be statistically significant.Result:①The NR area in amiodarone group decreased significantlythan that of I/R group(41.42±5.65vs.55.12±7.84,P＜0.05);②C ompared withthat of sham group,the activity of SOD(μ/ml)was significantlylowered(339.14±9.52vs.479.04±8.74,431.55±4.75vs.479.04±8.74),andcontent of MDA(nmol/ml)was signicantly elevated(29.65±1.01vs.5.86±0.65，23.75±1.31vs.5.86±0.65),(both P＜0.05)in I/R and AMgroup;Compared with that of I/R group,the activity of SOD(μ/ml)wassignificantly elevated(431.55±4.75vs.339.14±9.52),and content ofMDA(nmol/ml)was signicantly lowered(23.75±1.31vs.29.65±1.01),(both P＜0.05);③Compared with that of shamgroup,apoptosis rate ofcardiomyocyte was significantly increased in I/R and AM group(16.01±1.50vs.3.47±0.67,7.02±1.13vs.3.47±0.67, P＜0.05）; Compared with thatof I/R group, apoptosis rate of cardiomyocyte was significantly decreased inAM group(7.02±1.13vs.16.01±1.50, P＜0.05);④Compared with that ofsham group,the expression of Bcl-2protein was increased(3.83±0.89vs.2.57±0.76,5.76±1.14vs.2.57±0.76),and Bax protein was increased(10.25±0.73vs.1.31±0.65,6.24±1.36vs.1.31±0.65) in I/R and AM group(both P＜0.05);Compared with that of I/R group,the expression of Bcl-2protein wasincreased(5.76±1.14vs.3.83±0.89, P＜0.05)；Bax protein was decreasedsignificantly in AM group(6.24±1.36vs.10.25±0.73, P＜0.05)；Comparedwith that of I/R group, the ratios of Bcl-2/Bax was increased significantly(0.92±0.28vs.0.37±0.14, P＜0.05).Conclusion: Amiodarone may ameliorate myocardial I/R injury andreduce the range of NR.The mechanism may inhibit the generation of oxygen free radicals and cardiomyocyte apoptosis through upregulate the ratio ofBcl-2/Bax proteins. |
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