睾酮对实验性心肌缺血/复灌损伤的防护作用及机制研究

CARDIOPROTECTION OF TESTOSTERONE IN RAT HEARTS SUBJECTED TO ISCHEMIA/REPERFUSION

目的:探讨睾酮对实验性心肌缺血/复灌损伤的效应,并观察睾酮对心肌细胞氧化应激损伤的影响。方法:大鼠双侧输精管结扎,睾丸摘除,每天补充丙酸睾酮(200μg/100 g体重)。给药8周后,大鼠开胸取心脏,Langendorff装置上离体灌流,建立心肌梗死模型,测定冠脉流出液中LDH含量,和心肌梗死面积。酶解法分离大鼠心室肌细胞,复制H_2O_2应激模型,测定单个心肌细胞收缩力学指标,以及测定心肌细胞线粒体ROS生成量。结果:在去势模型中,丙酸睾酮处理显著地减少缺血/复灌后心肌梗死面积和冠脉流出液中LDH释放量。在分离的心肌细胞中睾酮预处理明显改善H_2O_2应激导致的±dL/dtmax和dL降低程度;睾酮(10^(-5)μmol/L)预处理能够减少H_2O_2应激引起的心肌细胞DCF荧光值增加,而此作用均能被ATP敏感性钾通道阻断剂5-HD和线粒体通透性转换孔(mPTP)开放剂atractyloside所取消。结论:睾酮具有对实验性心肌缺血/复灌损伤的防护作用,而这种保护作用可能与其抑制线粒体通透性转换孔开放或/和促进线粒体ATP敏感性钾通道开放有关。

Ahn： To investigate the chronic cardioprotecfion of testosterone against isehemia/reperfusion injury and acute effect against H2O2-stress injury. Methods： The vas deferens were ligated bilaterally and the testes removed from male Sprague-Dawley rats, and testosterone propionate was supplemented every day. Eight weeks after gonadeetomy, all the hearts were mounted on a Langendorff apparatus to assess the level of lactate dehydrogenase（LDH） in the coronary effluent and the infarct size. Isolated adult ventrieular myocytes were obtained by enzymatic dissociation, in which H2O2-stress injury model was copied. The myocyte contraction was determined, and mitochondrial reactive oxygen species （ROS） production was measured by loading with fluorescent probe DCFH-DA. Results： In gonadectomy model, pretreatment with testosterone propionate significantly decreases the LDH release and the infarct size. In the isolated myocytes model, testosterone attenuated the decreases of ±dL/dtmax and dL which produced by H2O2-stress, and prevented the production of ROS induced by H2O2-stress. Co-treatment with atracty- loside or 5-HD attenuated the effect of testosterone. Conclusion： The findings show the chronic cardioprotection of testosterone against isehemia/reperfusion injury and acute effect against H2O2-stress injury via opening of mitoKATP channel or/and the inhibiting mitochondrial permeability transition pore.