Tate J M, Oberpriller J O, Oberpriller J C
Department of Anatomy and Cell Biology, University of North Dakota School of Medicine, Grand Forks 58202.
Tissue Cell. 1989;21(3):335-42. doi: 10.1016/0040-8166(89)90048-7.
Cell division in the adult cardiac myocyte has been examined in a number of different species in vivo and in vitro. The newt cardiac myocyte responds to trauma in vivo with proliferation. It has recently been successfully placed into cell culture. The purpose of the present study was to analyze the process of DNA synthesis in these cultures. The myocytes were cultured in modified Leibovitz L-15 medium on a bovine corneal endothelial cell membrane carpet and were incubated with tritiated thymidine (1 microCi/ml) for 24 hr prior to fixation at 10, 15, 20 and 30 days. Labeling indices were determined to be 10.5 +/- 2.5, 16.5 +/- 2.8, 10.5 +/- 2.2, and 2.9 +/- 0.6, respectively. When myocytes were exposed to 1 microCi/ml tritiated thymidine continuously from the fifth to the thirtieth day in culture, the labeling index was 34.5 +/- 6.8. Comparison of DNA synthesis in the in vivo and in vitro systems indicated comparable patterns, although there was an earlier onset of activity in culture. Between 8 and 15 days in culture, myocyte mitoses were regularly observed. Myocytes in metaphase contained well-organized myofibrillae, suggesting that mitosis may occur with highly differentiated morphology in vitro. It appears that this system will be useful in the definition of mechanisms involved in both initiating and stopping proliferative events in the cardiac myocyte.
成年心肌细胞的细胞分裂已在多种不同物种体内和体外进行了研究。蝾螈心肌细胞在体内对创伤会产生增殖反应。最近它已成功用于细胞培养。本研究的目的是分析这些培养物中DNA合成的过程。将心肌细胞在改良的Leibovitz L - 15培养基中培养在牛角膜内皮细胞膜铺片上，并在固定前10、15、20和30天用氚标记的胸腺嘧啶核苷（1微居里/毫升）孵育24小时。标记指数分别测定为10.5±2.5、16.5±2.8、10.5±2.2和2.9±0.6。当心肌细胞在培养的第5天至第30天连续暴露于1微居里/毫升的氚标记胸腺嘧啶核苷时，标记指数为34.5±6.8。体内和体外系统中DNA合成的比较表明模式相似，尽管培养中活性出现得更早。在培养的第8天至第15天之间，经常观察到心肌细胞有丝分裂。处于中期的心肌细胞含有组织良好的肌原纤维，这表明在体外有丝分裂可能在高度分化的形态下发生。看来这个系统将有助于确定参与启动和停止心肌细胞增殖事件的机制。
