Objectives: To investigate the effects and mechanisms of Nardostachys chinensis (NC) on spontaneous ventricular arrhythmias in rats with hyper-acute myocardial infarction (AMI).
Methods: Seventy-two rats were randomly divided into the control group (n = 24), metoprolol group (n = 24), and the NC group (n = 24). Premature ventricular contractions (PVCs), ventricular tachycardias (VTs), ventricular fibrillations (VFs), and blood pressure were monitored for 4 hours after coronary artery ligation. The connexin 43 (Cx43) expression in ventricular myocardium was measured by immunohistochemistry, Western blot, and real-time RT-PCR.
Results: Compared with the control, metoprolol and NC decreased the VF incidence (50% vs. 4.2%, P < 0.001, and 50% vs. 12.5%, P = 0.005, respectively). There was a steady decrease in the cumulative number of PVCs and VTs within 4 hours from ligating in 3 groups. Compared with the control, metoprolol and NC reduced the cumulative number of VTs and PVCs. Compared with control, metoprolol and NC decreased the infarct size of the left ventricular tissue (55.98% ± 6.20% vs. 39.13% ± 4.53%, P < 0.001, and 55.98% ± 6.20% vs. 42.39% ± 3.44%, P < 0.001, respectively). The results from immunohistochemistry, Western blot, and real-time RT-PCR showed that the protein expression of Cx43 in the control group was significantly lower than that in the metoprolol and NC groups in the infarcted zone.
Conclusions: NC decreased the incidence of spontaneous ventricular arrhythmias (especially VF), reduced Cx43 degradation, and improved Cx43 redistribution in myocardial infarcted zone in rats with hyper-AMI. The data of the present study indicated that NC may be a promising drug in the future to prevent patients with AMI from lethal ventricular arrhythmias in prehospital setting.
*Department of Cardiovascular Medicine, The First Affiliated Hospital, and the Key Laboratory of Assisted Circulation, Ministry of Health, Sun Yat-Sen University, Guangzhou, China; and
†Department of Ultrasonography, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
Reprints: Su-Hua Wu, MD, PhD, Department of Cardiovascular Medicine, The First Affiliated Hospital, Sun Yat-Sen University, No. 58, Zhongshan Rd II, Guangzhou 510080, China (e-mail: firstname.lastname@example.org).
J. Zhang, C.-C. Qiang, and W.-J. Li have contributed equally. Study concept and design: S.-H. Wu; acquisition of data: J. Zhang, C.-C. Qiang, W.-J. Li, L.-J. Liu, X.-X. Lin, Y.-J. Cheng, K. Tang, F.-J. Yao; analysis and interpretation of data: J. Zhang, C.-C. Qiang, W.-J. Li, S.-H. Wu, L.-J. Liu, X.-X. Lin, Y.-J. Cheng, K. Tang, F.-J. Yao; drafting of the manuscript: J. Zhang, S.-H. Wu, C.-C. Qiang, W.-J. Li; statistical analysis: J. Zhang, C.-C. Qiang, W.-J. Li.
Supported by National Natural Science Foundation of China (No. 81370285), Guangdong Province Natural Science Foundation (No. 06021338); Guangdong Province Science and Technology Program (No. 2012B031800091, 2007B031508003) and National Ministry of Education Scholarly Exchanges Foundation (No. 200724). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
The authors report no conflicts of interest.
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Received January 15, 2014
Accepted March 10, 2014