Department of Cardiology, Zhongda Hospital, Medical School of Southeast University Nanjing, China.
Am J Transl Res. 2013 Apr 19;5(3):327-35. Print 2013.
Loss of cardiomyocytes after myocardial infarction (MI) causes heart failure. In this study, we investigate whether the in situ cardiomyocytes can re-enter the cell cycle and to what extent cell division of cardiomyocytes occurs after acute MI (AMI) in rats.
Sprague Dawley (SD) rats were used in this study; the left anterior descending coronary artery was ligated. At time points (3 days, 1 week, 2 weeks, 3 weeks, and 4 weeks) after the operation, five rats were euthanized, respectively. An additional five sham-operated rats serves as a control group and were euthanized at 3 days post-operation. The expressions of cyclin A2, Ki-67, phospho-histone H3 (H3P), and Aurora B in myocardial tissues were detected by Western blot and immunofluorescence.
The expression levels of cyclin A2 were significantly higher in all groups with AMI except the 4-week group than those found in the sham-operated group (P < 0.01). The percentage of Ki-67-positive nuclei in the border zones was significantly higher than the percentage in the distant normal myocardium (P < 0.01).
our results demonstrate that cardiomyocytes re-enter the cell cycle after AMI and that cyclin A2 is a reliable marker for the detection of cell cycle activity in cardiomyocytes.
心肌梗死后心肌细胞的丢失会导致心力衰竭。在这项研究中，我们研究了在大鼠急性心肌梗死（AMI）后，原位心肌细胞是否可以重新进入细胞周期，以及心肌细胞分裂的程度。
本研究使用 Sprague Dawley（SD）大鼠；结扎左前降支冠状动脉。手术后的时间点（3 天、1 周、2 周、3 周和 4 周），分别处死 5 只大鼠。另外 5 只假手术大鼠作为对照组，在手术后 3 天处死。通过 Western blot 和免疫荧光检测心肌组织中细胞周期蛋白 A2、Ki-67、磷酸化组蛋白 H3（H3P）和 Aurora B 的表达。
除 4 周组外，所有 AMI 组的 cyclin A2 表达水平均明显高于假手术组（P < 0.01）。边缘区 Ki-67 阳性核的百分比明显高于远侧正常心肌的百分比（P < 0.01）。
我们的结果表明，AMI 后心肌细胞重新进入细胞周期，细胞周期蛋白 A2 是检测心肌细胞周期活性的可靠标志物。
