Objective Chronic myocardial ischemia (CMI) has become the most importat cause of heart failure (HF) all over the world. The aim of the current study was to investigate the effects of Sarcoendoplasmic reticulum calcium ATPaee 2a (SERCA2a) gene transfer on cardiac function and endoplasmic reticulum stress (ERS) associated myocardial apoptosis in a minipig HF animal model induced by CMI. Methods HF was induced in minipigs by implantation of ameroid constrictor in the initial segment of left anterior descending (LAD) branch of coronary artery. After confirmation of myocardial perfusion defects and cardiac function impairment by myocardial perfusion imaging and echocardiography, animals were divided into 4 groups (n =4 each): HF group, HF + enhanced green fluorescent protein (EGFP) group,HF + SERCA2a group, and shamed animals as control group. A total amount of 1×1012 v.g. Of rAAV1EGFP or rAAV1-SERCA2a were injected intramyocardially to each animal of HF + EGFP and HF +SERCA2a groups. Sixty days after gene transfer, protein level and activity of SERCA2a were examined,cardiac functions and changes of serum inflammatory and neuro-hormonal factors were determined. Apoptotic index of the ischemic myocardium, protein levels of ER stress marker glucose regulated protein 78 ( GRP 78) and ER stress specific apoptotic marker caspase-12 were also assayed. Results At the study end,echocardiographic and hemodynamic measurements indicated a significant improvement of both cardiac systolic and diastolic function in HF + SERCA2a group compared with HF/HF + EGFP groups [LVEF (60.2±8.6)%vs (44.2±7.1)% and (46.8±6.7)%, Ev/Ay 1.28±0.24 vs 0.77 ±0.17 and 0.80±0.21, +dp/dtmax(2713.9 ±434.0) mm Hg/s ( 1 mm Hg =0.133 kPa) vs (1892.3 ±434.2) mm Hg/s and (1931.2±397.4)mm Hg/s, -dp/dtmax (1422.1±334.4) mm Hg/s vs (848.3±308.3) mm Hg/s and (849.5±278.3)mm Hg/s, P＜0.05], along with increase in both SERCA2a protein level (1.13±0.26 vs 0.73 ±0.17 and 0.64±0.18, P＜0.05) and activity [(16.2±5.5) IU/ml vs (7.9±3.1) IU/ml and (7.5 ±2.8)IU/ml, P ＜0.05] compared with HF/HF + EGFP groups. Serum concentrations of inflammatory factor tumor necrotic factor α [(382.3±114.4) ng/L vs (732.3±201.4) ng/L and (689.8±192 5) ng/L, P＜0. 05], neural-hormonal factors brain natriuretic peptide [(142.6±45.3) ng/L vs (422.3±113.6) ng/L and(393.7 ±103.3)ng/L, P＜0.01], endothelin-1 [(111.4 ±37.5)ng/L vs (193.5 ±54.3)ng/L and (201.0±72.1)ng/L,P＜0.05] and angiotensin Ⅱ[(189.7±65.2)μg/L vs (538.3 ± 135.2) μg/L and ( 525.5±144.1)μg/L, P＜0.01] were also significantly decreased in HF + SERCA2a group compared with HF/HF + EGFP groups. The apoptotic index [(12.71±4.11)% vs(23.22±7.23) % and (24.31±6.38)%, P＜0.05], protein levels of GRP78 (1.27±0.33 vs 3.23±1.14 and 4.18±1.13, P＜0.05)and protein level ratios of cleaved caspase-12 to total caspase-12[(4.62±1.93)% vs (9.71±2.70)% and (10.14±2.81)%, P＜0.05] were also significantly reduced in the ischemic myocardium of HF+SERCA2a group compared with the HF/HF + EGFP groups. Conclusion Overexpression of SERCA2a significantly improved cardiac systolic and diastolic function in this HF model partly through attenuation of ER stress related myocardial apoptosis, suggesting its therapeutic potential for CM1 related heart failure.%目的 研究肌浆网钙ATP酶2a(SERCA2a)基因过表达对慢性缺血性心力衰竭(心衰)心功能及心肌内质网应激(ERS)相关凋亡的影响.方法采用ameroid环束扎小型猪前降支制备慢性缺血性心衰模型.开胸心肌内注射重组腺相关病毒以过表达SERCA2a或对照报告基因绿色荧光蛋白.60 d后检测血流动力学、SERCA2a的表达和活性、心肌凋亡及ERS标志蛋白-分子伴侣GRp78、凋亡蛋白caspase-12的表达.结果基因转导后60 d,与心衰对照及报告基因组相比,转基因组SERCA2a蛋白表达和活性显著增高,心功能参数改善,心肌凋亡指数降低,伴GRP78和活化caspase12表达下降.结论过表达SERCA2a可改善慢性缺血性心衰的心脏功能,其机制可能涉及减轻ERS相关的心肌细胞凋亡.
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