中文摘要：

目的验证老年大鼠心肌细胞凋亡程度；测定老年心肌组织中内源性线粒体后凋亡调节蛋白Omi／HtrA2和XIAP的表达及其与心肌细胞凋亡的关系。方法分别选取雄性成年SD大鼠[体重（278±10）g，4-6个月]和老年SD大鼠[体重（525±8）g，22-24个月]。随机分为以下4组：正常成年组（40只）；正常老年组（40只）；老年ucf～101组（10只），腹腔注射ucf-101（1．5μmol／kg）；老年DMSO组（10只），腹腔注射DMSO（1．5μmol／kg）。采用Caspase-3活性测定法检测大鼠心肌组织中心肌细胞凋亡发生情况；用Western—blot蛋白印记法检测大鼠心肌组织中Omi／HtrA2和XIAP的表达水平。结果以成年大鼠caspase-3比活性（1．00±0．04）为1，老年大鼠的caspase-3的比活性（2．31±0．43，P〈0．01）显著增高。老年大鼠心肌组织中Omi／HtrA2表达明显增高，XIAP表达明显下降。给予特异性Omi／HtrA2的抑制剂ucf-101，可显著减少老年大鼠心肌组织caspase-3的表达。结论老年大鼠心肌组织中表达增多的Omi／HtrA2，可能导致了XIAP的降解以及随后的caspase-3活化和细胞凋亡。

英文摘要：

Objective To demonstrate whether apoptosis index is changed in aging heart; and investigate pro-apoptotic Omi/HtrA2 and anti-apoptotic XIAP expression associated with enhanced myocardial apoptosis of aging heart. Methods Male Sprague-Dawley adult rats [weight （278±10）g,4-6 months] and aging rats [weight （525±8）g,22-24 months] were randomly divided into four groups： Normal Young Group （n=40）,Normal Aging Group （n=40）,Normal Aging Group±ucf-101 （n=10）：Administrate ucf-101 （1.5 μmol/kg） via intraperitoneal injection,Normal Aging Group±DMSO （n=10）： Administrate DMSO （1.5 μmol/kg） via intraperitoneal injection. Myocardial apoptosis was analyzed by Caspase-3 activity assay. The protein expression level of Omi/HtrA2 and XIAP were determined by western-blot. Results Compared to the Caspase-3 activity ratio of young group （1.00± 0.04） the old group was enhanced significantly （2.31±0.43,P〈0.01）. There is increased Omi/HtrA2 expression （P〈0.05） and decreased expression of XIAP （P〈0.05） in the aging heart. Treatment with ucf-101, a novel and specific Omi/HtrA2 inhibitor attenuated caspase-3 activity （P〈0.05）. Conclusion Omi/HtrA2 increasing may result in XIAP degradation caspases-3 activation, and subsequent apoptosis in aging heart.