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目的 观察外源性的 NO供体硝普钠对培养心肌细胞 DNA的损伤情况以及超氧化物歧化酶 ( SOD)和过氧化氢酶 ( CAT)的保护作用。方法 采用离体培养乳鼠心肌细胞和单细胞凝胶电泳技术 ,根据硝普钠浓度的不同和加入的自由基清除剂 SOD、CAT的不同进行分组实验。结果 外源性的 NO供体硝普钠与离体培养的乳鼠心肌细胞共培养 5小时后 ,单细胞凝胶电泳检测有典型的彗星样改变 ,并随剂量的增加其 DNA迁移度和细胞迁移率也随之增加 ,与对照组相差显著 ( P<0 .0 1) ;加入 SOD或 CAT均能明显减轻这种彗星样改变 ,二者合用效果最为显著 ( P<0 .0 1)。结论 高浓度的硝普钠严重损伤心肌细胞 DNA,自由基清除剂对此有保护作用。这在一定程度上说明 ,高浓度的 NO能导致心肌细胞 DNA单链的明显损伤 ,这可能是在某些病理条件下造成心肌细胞损伤或死亡的重要机制。
Objective To observe the DNA damage induced by exogenous NO donor sodium nitroprusside and the protective effect of superoxide dismutase (SOD) and catalase (CAT) in cultured myocardial cells. Methods Rat neonatal rat cardiomyocytes and single-cell gel electrophoresis were used to divide the SOD and CAT free radicals according to the concentration of sodium nitroprusside. Results Exogenous NO donor sodium nitroprusside and cultured rat neonatal cardiomyocytes co-cultured for 5 hours, single cell gel electrophoresis detected a typical comet-like changes, and with increasing dose of DNA migration and cell The migration rate also increased significantly compared with that of the control group (P <0.01). The addition of SOD or CAT significantly reduced this kind of comet-like change, and the combination effect was the most significant (P <0.01). Conclusion High concentration of sodium nitroprusside severely damages DNA of cardiomyocytes, and the free radical scavenger has a protective effect on it. To a certain extent, this shows that high concentrations of NO can lead to significant single-stranded DNA damage in cardiomyocytes, which may be an important mechanism of cardiomyocyte injury or death under certain pathological conditions.