Herbs Protect against Doxorubicin-induced Cardiotoxicity

说明(申请人提供)：阿霉素(Dox)是一种常用的抗肿瘤药物，用于治疗血液系统恶性肿瘤和实体瘤已超过30年。然而，它的使用在很大程度上受到累积剂量相关的心脏毒性的限制，包括心肌病和充血性心力衰竭。心脏毒性的一个核心机制是产生活性氧(ROS)，在ROS中，Dox产生超氧化物、过氧化氢和羟基自由基，导致线粒体损伤。许多抗氧化剂已经被用来预防和减少Dox引起的心脏毒性，但效果参差不齐。根据我们对缺血/再灌注损伤的细胞学研究，某些草药抗氧化剂在减轻线粒体氧化损伤方面可能比传统抗氧化剂更有效，因此可能在预防Dox的心脏副作用方面发挥重要作用。这项拟议的工作测试了两种高效的草本抗氧化剂，葡萄籽原花青素提取物(GSPE)和黄芩提取物(SBE)是否可以在我们的心肌细胞模型中预防Dox诱导的心脏毒性。 我们将测试1)Dox是否增加心肌细胞线粒体的氧化应激和损伤，测试暴露(1-24小时)增加剂量的Dox(1-100 um)是否会增加鸡心肌细胞的氧化应激和死亡，测量DCFH和DHE的氧化分别作为过氧化氢、羟基自由基和超氧化物产生的指示物，以及摄取碘化丙啶作为细胞死亡的标志。我们还将观察Dox暴露引起的细胞膜形态和同步收缩的变化，以测试其对该模型收缩功能的影响。我们还将测试Dox诱导的ROS产生是否来自线粒体还是非线粒体来源。然后，我们将测试2)GSPE(1-100_ug/ml)和SBE(0.1-1 mg/ml)单独或联合应用是否能够减少Dox诱导的ROS的产生，并减轻ROS介导的损伤。我们将把这些保护作用与其他抗氧化剂，如生育酚和N-乙酰半胱氨酸进行比较。最后，我们将确定GSPE或SBE是否影响Dox对癌细胞的杀瘤作用。 这项工作有可能增加我们对Dox氧化剂心脏毒性的了解，并可能导致草药抗氧化剂治疗的新应用，使Dox更安全和更有效。

DESCRIPTION (provided by applicant): Doxorubicin (Dox) is an anthracycline antineoplastic drug commonly used against hematologic malignancies and solid tumors for over 30 years. However, its use is largely limited by a cumulative dose-related cardiotoxicity, which includes cardiomyopathy and congestive heart failure. A central mechanism of cardiotoxicity involves generation of reactive oxygen species (ROS), in which Dox generates superoxide, hydrogen peroxide, and hydroxyl radicals leading to mitochondrial damage. Many antioxidants have been used to prevent and minimize Dox-induced cardiotoxicity, but with mixed results. Based upon our cellular studies of ischemia/reperfusion injury, some herbal antioxidants may be more potent than traditional antioxidants in attenuating mitochondrial oxidant injury, and thus could play an important role in preventing cardiac side effects of Dox. The proposed work tests whether two highly effective herbal antioxidants, grape seed proanthocyanidin extract (GSPE) and Scutellaria baicalensis extract (SbE), can prevent Dox-induced cardiotoxicity in our cardiomyocyte model. We will test whether 1) Dox increases mitochondrial oxidant stress and injury in cardiomyocytes, testing whether exposure (1-24 hours) to increasing doses of Dox (1 -100 uM) increases oxidant stress and death in chick cardiomyocytes, measuring oxidation of DCFH and DHE as indicators of hydrogen peroxide, hydroxyl radicals and superoxide generation respectively, and uptake of propidium iodide as a marker of cell death. We will also observe changes in cell membrane morphology and synchronous contractions as a result of Dox exposure to test its effect on contractile function in this model. We will also test whether Dox-induced ROS generation originates from mitochondrial versus nonmitochondrial sources. We will then test whether 2) GSPE (1-100 _ug/ml) and SbE (0.1 -1 mg/ml) individually or in combination, can attenuate Dox-induced ROS generation and ameliorate ROS-mediated injury. We will compare these protective effects to other antioxidants such as tocopherol and N-acetylcysteine. Finally, we will 3) determine whether GSPE or SbE affect the tumoricidal action of Dox on cancer cell lines. This work has the potential to increase our understanding of Dox oxidant cardiotoxicity, and could lead to new applications for herbal antioxidant treatment, which make Dox safer and more effective.