阿霉素是乳腺癌辅助化疗常用药物，但存在剂量依赖性的心脏毒性，当剂量超过550mg/m2时尤为明显，且不可逆。因此，寻找减低阿霉素心脏毒作用的药物具有重要临床意义。阿霉素的心脏毒性是多因素共同作用的结果，如活性氧的生成、钙超载、线粒体损伤、细胞凋亡和自噬等，其中氧化应激在阿霉素的毒性效应中起重要的作用。《神农本草经》记载桔梗主胸胁痛如刀刺，幽幽惊恐悸气，具有活血、行气、化痰作用，药理研究也发现桔梗有较好的抗氧化损伤作用。本研究拟在乳腺癌肺转移小鼠模型基础上，建立阿霉素致心肌受损模型，通过体内实验，动态观察阿霉素致小鼠心肌受损的过程，从心超、心脏病理、拓扑异构酶2β（top2β）以及活性氧（ROS）、超氧化物歧化酶(SOD）、丙二醛（MDA）等氧化因子等角度研究桔梗对阿霉素致小鼠心肌受损的减毒作用及其机制，并研究桔梗与阿霉素合用对乳腺癌肺转移的疗效影响。

Adriamycin is a commonly used drug in the adjuvant chemotherapy of breast cancer, but there is a dose-dependent cardiac toxicity. When the dose is more than 550mg/m2, the cardiac toxicity is more obvious, and it is not reversible. Therefore, it is of great clinical significance to find a drug to reduce the cardiac toxicity of adriamycin. Doxorubicin induced cardiotoxicity is the results of interaction of multiple factors, such as reactive oxygen species formation, calcium overload, mitochondrial damage, cell apoptosis and autophagy, which oxidative stress in the toxic effect of adriamycin play an important role. The Shennong Bencao "records of Platycodon grandiflorum main in chest and hypochondrium pain such as knife, faint panic palpitation gas, has the functions of promoting blood circulation, Qi, phlegm role, pharmacological studies also found that better antioxidant effect of Platycodon grandiflorum. This study intends to in breast cancer with lung metastasis mouse model based on establish the adriamycin induced myocardial damage model, through in vivo experiments, the dynamic observation of adriamycin induced mice myocardial damage process, from the heart, cardiac pathology, top2 beta and ROS, SOD, MDA and oxidation factor angle for the research of Platycodon grandiflorum on adriamycin induced mouse myocardial damage of reducing toxicity and mechanism of, and research of Platycodon grandiflorum and adriamycin combination of lung metastases from breast cancer the curative effect.