Apoptosis of hypertrophic cardiomyocytes stimulated by hypoxia-reoxygenation is partially mediated by apoptosis-inducing factor
- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 6
- DOI:
- 10.3321/j.issn:0371-0874.2006.06.013
- Key Word:
- 心肌肥大;细胞凋亡;缺氧/复氧;凋亡诱导因子
Abstract： 心肌细胞凋亡导致心肌组织合胞体功能丧失,最终使代偿性心肌肥大向心力衰竭转化.过去的研究已经确认天门冬氨酸特异性半胱氨酸蛋白酶(caspartate-specific cysteinyl proteinase,caspase)依赖机制在心肌细胞凋亡中的作用,但对caspase非依赖机制即凋亡诱导因子(apoptosis-inducing factor,AIF)在心肌细胞凋亡中的作用尚不明确.本研究应用血管紧张素Ⅱ(0.1μmol/L培养12 h)诱导培养的小鼠肥大心肌细胞,利用三气孵箱建立缺氧/复氧模型以模拟缺血再灌注.应用RT-PCR、Western blot、siRNA基因转染、Hoechst 33258染色法检测AIF在Mrna和蛋白质水平的表达及细胞凋亡的变化,分析AIF在缺氧/复氧致肥大心肌细胞凋亡中的意义.结果如下:(1)与对照组比较,缺氧8 h组(H8h)和缺氧12 h组(H12h)AIF Mrna及蛋白表达水平均显著升高(Mrna:0.52±0.04及0.85±0.10 vs 0.29±0.08,P＜0.05;蛋白质:2.07±0.15和3.12±0.19vs 0.29±0.04,P＜0.05),即随缺血时间的延长,AIF Mrna及蛋白表达水平均显著增加.(2)与对应单纯缺氧组比较,缺氧后给予复氧刺激,H8h/R组和H12h/R组AIF Mrna及蛋白表达水平均显著升高(Mrna:1.09±0.12和1.41±0.23,P＜0.05;蛋白质:4.57±0.25和5.71±0.27,P＜0.05).仅在H8h/R及H12h/R组,可见AIF核转位显著增加.(3)AIF siRNA转染可显著抑制肥大心肌细胞AIF的表达,对缺氧时细胞凋亡无明显影响(P＞0.05),但可显著降低缺氧/复氧诱导的肥大心肌细胞凋亡率(P＜0.05).同时抑制AIF及caspase-3活性,可显著加强单一抑制剂对缺氧/复氧诱导的肥大心肌细胞凋亡的抑制作用.(4)抑制caspase-3活性对缺氧/复氧诱导的AIF核转位无明显影响.上述结果提示,缺氧/复氧时AIF Mrna、蛋白表达和核转位均显著增加,且在缺氧/复氧诱导肥大心肌细胞凋亡中具有重要的作用.
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