Long-term effects of cardiac stem cells transplantation to improve the electrophysiological stability and ventricular fibrillation threshold after myocardial infarction

Chen Li-peng; Yan Ping; Guo Tian-zhu; Hou Jing-ying; Zheng Shao-xin; Zhou Chang-qing; Long Hui-bao; Zhong Ting-ting; Wang Tong

doi:10.3969/j.issn.2095-4344.2015.10.008

Abstract：BACKGROUND:Our previous work has demonstrated that the electrophysiological stability and ventricular fibrilation threshold were distinctly improved in rats with myocardial infarction 6 weeks after cardiac stem cels transplantation (short- to mid-term). OBJECTIVE: To observe the long-term effects of cardiac stem cels transplantation on the ventricular fibrilation threshold and electrophysiological stability in rats with heart failure post myocardial infarction. <br> METHODS: Twenty Sprague-Dawley rats with myocardial infarction were induced by the left anterior descending coronary artery ligation. Two weeks later, animals were randomized to receive the injection of cardiac stem cels labeled with PKH26 in PBS or PBS alone into the local infarct zone. Twelve weeks after the cardiac stem cels or PBS injection, the electrophysiological characteristics and ventricular fibrilation threshold were measured at the infarct zone, the infarct marginal zone and the non-infarct zone. Labeled cardiac stem cels were detected and the expression of connexin-43 and α-sarcomeric actin was examined in cryostat sections from each harvested heart. RESULTS AND CONCLUSION:Compared with the PBS group, no significant differences were revealed in the unipolar electrogram activation recovery time and the correct activation recovery time in the infarct zone, the infarct marginal zone and the non-infarct zone in the cardiac stem cels group at 12 weeks post the cel transplantation (P > 0.05). There were no remarkable differences in the correct activation recovery time dispersion and induced malignant ventricular arrhythmias between the two groups (P > 0.05). No obvious differences were discovered in the ventricular fibrilation threshold in the infarct zone and infarct marginal zone in the cardiac stem cels group in contrast to the PBS group (P > 0.05), though a statistical significance could be found in the non-infarct zone between the two groups (P < 0.05). Labeled cardiac stem cels were identified in the infarct marginal zone and expressed connexin-43 and α-sarcomeric actin. It suggested that the beneficial effects of cardiac stem cels in modulating the electrophysiological stability and improving the ventricular fibrilation threshold faded away 12 weeks after cel transplantation. However, the mechanisms involved remained unclear.