缺氧对心肌细胞DNA链损伤的体外实验研究

目的 :研究缺氧条件下对体外培养的心肌细胞DNA链的损伤及其探讨损伤机制。方法 :利用单细胞电泳技术结合激光扫描共聚焦显微镜来观察乳鼠心肌细胞的DNA损伤 ,以慧星样细胞出现率、慧尾长度和尾距 (尾部DNA占总DNA的百分比与头尾部中心间距的乘积 )来评价心肌细胞DNA的损伤程度。结果 :缺氧 12h后 ,心肌细胞DNA发生了损伤 ,慧星样细胞出现率、慧尾长度和尾距均增加 ,与对照组有显著差异 (P <0 .0 5 ) ;并随缺氧时间的延长 ,DNA的损伤程度和慧星样细胞的出现率均随之增加 ,呈现明显的时间———效应趋势。结论 :单细胞电泳可快速、灵敏地检测缺氧引起的心肌细胞DNA损伤。缺氧导致细胞的DNA损伤可能是诱导心肌细胞凋亡发生的重要机制之一。

In Vitro Study on the DNA Damages of the Cardiomyocytes Induced by Hypoxia

Objective: Single cell gel elecrophoresis(SCGE) assay was used to observe the damage of DNA strand induced by hypoxia in cultured neonatal rat cardiomyocytes. Methods: DNA damage was measured by single gel elecrophoresis and laser scanning confocal microscopy.The degree of DNA damage was judged by the percentage of cardiomyocytes with comet like tail, the tail length and tail moment of the cell. Results: In comparison with control group, the DNA strands were damaged significantly after hypoxia for 12 hour. Hypoxia increased the percentage of comet cells in a time-dependent manner. Conclusion: SCGE was a fast and sensitive method to detect the DNA damages of the cardiomycytes induced by hypoxia. It suggests that the DNA damages might be one of important mechanisms of cardiomyocytes apoptosis induced by hypoxia.