OBJECTIVES: To verify the hypothesis that growth differentiation factor 11 (GDF11) attenuates myocardial ischemia/reperfusion (MI/R) injury and explore the underlying mechanism. METHODS: To simulate MI/R injury, H9C2 cells were incubated in an anaerobic chamber (95% N2+5% CO2) for 9 h followed by 3 h of reoxygenation in the presence of GDF11 (10 nmol/L). The cells exposed to hypoxia/reoxygenation (H/R) or sham exposure were treated with GDF11 alone or in combination with the iNOS inhibitor 1400W, the Trx1 nitration inhibitor EUK134, human recombinant Trx1 (hTrx1) or N-Trx1, and the changes in cell viability was determined by MTT assay and LDH release assay. Cardiomyocyte apoptosis was determined by TUNEL staining and caspase-3 activity assessment, and oxidative stress levels were evaluated by measuring superoxide production and DHE staining. Nitrative stress in the cells was assessed by measuring total NO content and nitrotyrosine content. The expression levels of iNOS, gp91phox, ASK1 and p-ASK1 were detected using Western blotting, Trx1 activity was determined using insulin disulfide reduction assay, and Trx1 nitration was analyzed by immunoprecipitation. RESULTS: In H9C2 cells with H/R exposure, 10 nmol/L GDF11 treatment significantly increased cell viability, decreased LDH release, inhibited caspase-3 activation and cell apoptosis, and reduced superoxide production, total NO content and nitrotyrosine production. GDF11 also significantly inhibited iNOS expression, reversed H/R-induced increase of Trx1 nitration and inhibition of Trx1 activity, and inhibited ASK1 phosphorylation. Treatment of the cells with 1400W decreased LDH release and caspase-3 activity, and diminished total NO production and nitrotyrosine production. EUK134 diminished LDH release and caspase-3 activation, upregulated Trx activity, and inhibited superoxide production in H9C2 cells. N-Trx1 abolished the protective effects of GDF11 against H/R injury in the cardiomyocytes. CONCLUSIONS: GDF11 protects cardiomyocytes against H/R injury partially by attenuating oxidative/nitrative stress and inhibiting Trx1 nitrative inactivation. 目的: 探究生长分化因子11（GDF11）是否能够减轻心肌缺血/再灌注（MI/R）损伤，并进一步探索其可能的机制。方法: 将培养的H9C2细胞置入厌氧培养室（95%N2+5%CO2）9 h后予以3 h复氧来模拟MI/R（SI/R）损伤。在复氧开始时将10 nmol/L的GDF11加入到细胞培养基中进行干预。实验分为:Sham组、Sham+GDF11组、SI/R组、SI/R+GDF11组。将iNOS抑制剂（1400W）及Trx1硝基化抑制剂（EUK134）干预分为:SI/R+1400W组、SI/R+EUK134组。SI/R+GDF11+hTrx1组、SI/R+GDF11+N-Trx1组分别为在GDF11干预的基础上分别给予重组人Trx1（hTrx1）、硝基化Trx1（N-Trx1）干预。采用MTT法及乳酸脱氢酶（LDH）释放水平检测细胞活力，TUNEL法及caspase-3活性检测心肌细胞凋亡，超氧化物水平及DHE染色法检测氧化应激水平，硝基酪氨酸含量及NO水平检测硝化应激水平，Western blotting法检测iNOS、gp91phox、ASK1、p-ASK1等蛋白表达水平，胰岛素二硫还原试验检测Trx1活性，免疫共沉淀法检测Trx1硝基化水平。结果: 与单纯SI/R组相比，10 nmol/L GDF11能够增加SI/R后心肌细胞活力、减少LDH释放、抑制caspase-3激活及心肌细胞凋亡（P<0.01），能够减弱心肌细胞DHE染色红色荧光、减少超氧化物生成（P<0.01）、降低细胞内总NO浓度以及硝基酪氨酸生成（P<0.01），能够抑制iNOS表达（P<0.01）、抑制Trx1硝基化水平（P<0.01）、增强Trx1活性（P<0.01），还能够抑制心肌细胞SI/R 后ASK1 磷酸化（P<0.01）。1400W能够减少心肌细胞LDH释放（P<0.01）、减弱caspase-3激活（P<0.01）、减少总NO生成（P<0.01）、减少硝基酪氨酸生成（P<0.05）。EUK134能够减少心肌细胞LDH释放（P<0.05）、降低caspase-3活性（P<0.01b）、升高Trx活性（P<0.01）、减少超氧化物生成（P<0.01）。N-Trx1能够阻断GDF11减少LDH释放（P<0.05）及抑制caspase-3活性的作用（P<0.05）。结论: GDF11可能通过减轻SI/R时氧化/硝化应激、抑制Trx1硝基化失活减轻心肌细胞凋亡，进而减轻MI/R损伤。.