本文主要探讨了铁皮石斛对缺血再灌注诱导心律失常的保护作用及机制。将健康雄性SD大鼠随机分为5组，每组12只，即对照组、模型组及铁皮石斛低、中、高剂量组[45、180和1080 mg/(kg·d)]。连续灌胃给药30 d后，除正常组外，其余各组结扎冠状动脉左前降支建立大鼠心肌缺血再灌注致心律失常模型，心电监测并记录再灌注15 min、30 min、1 h、2 h、4 h和24 h内心律失常出现的时间、持续时间及各组室性早搏（VP）、室性心动过速（VT）及死亡发生率。检测血浆中心钠肽（ANP）、脑钠肽（BNP）、心肌肌钙蛋白Ⅰ（cTn-Ⅰ）浓度，检测心肌组织中超氧化物歧化酶（SOD）和丙二醛（MDA）水平。结果显示铁皮石斛可缩短心律失常恢复正常时间，显著降低心律失常评分。缺血再灌注诱导的心律失常大鼠血浆中ANP、BNP和cTn-Ⅰ的水平显著上升，心肌组织中SOD浓度降低，MDA浓度升高，铁皮石斛可剂量依赖性的抑制上述效应。本研究表明铁皮石斛对缺血再灌注诱导的心律失常具有保护作用，机制涉及其抗氧化作用。

The protective effects and underlying mechanisms of Dendrobium candidum on ischemia reperfusion-induced arrhythmia were explored. Healthy male Sprague Dawley (SD) rats were randomly divided into five groups (n=12), including control group, model group, and three Dendrobium candidum groups, high-dose [1080 mg/(kg?d)], medium-dose [180 mg/(kg·d)], and low-dose [45 mg/(kg?d)]. After intragastric administration for 30 d, except for the control group, ligation of the anterior interventricular branch of the left descending coronary artery was performed to establish a mouse model of myocardial ischemia reperfusion-induced arrhythmia. Lead II electrocardiograms were recorded, and the time of arrhythmia onset, duration of arrhythmia, and incidences of ventricular premature (VP) beats, ventricular tachycardia (VT), and mortality in each group were examined and recorded at different reperfusion time points (15 min, 30 min, 1 h, 2 h, 4 h, and 24 h). Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and cardiac troponin I (cTn-I) in plasma. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels in myocardial tissue were determined using corresponding test kits. The results showed that Dendrobium candidum could shorten the recovery time after arrhythmia and significantly decrease the arrhythmia score. The ANP, BNP, and cTn-I levels in plasma of the rats with ischemia reperfusion-induced arrhythmia were increased, the SOD level in myocardium was decreased, and the MDA level was increased. Dendrobium candidum could inhibit these effects. This study indicated that Dendrobium candidum showed a protective effect on ischemia reperfusion-induced arrhythmia, and the mechanism might involve its antioxidant activity.

中南大学中央高校基本科研业务费专项资金资助（2016zzts497）；中南大学大学生创新课题资助项目（201610533575）