Pinamonti S, Chicca M C, Muzzoli M, Papi A, Fabbri L M, Ciaccia A
Department of Evolutionary Biology, University of Ferrara, Italy.
Free Radic Biol Med. 1994 Mar;16(3):363-71. doi: 10.1016/0891-5849(94)90038-8.
Clastogenic factors (CF) are diffusible molecules that damage DNA. They are generated within biological media by a variety of physical and chemical stimuli. Their nature and mechanism of action remain largely unknown. Clastogenic activity can be experimentally generated by pulsed ultrasound treatment of human serum. To investigate whether oxygen radicals are involved in the clastogenic activity induced by sonication of human serum, we examined the effects on such clastogenic activity of different oxygen radical scavengers added to human serum before and after sonication. Human serum was sonicated for 50 min at 24 microW/cm2 by pulsed ultrasound. The clastogenic activity of sonicated human serum was examined in the presence or absence of oxygen radical scavengers by measuring the amount of DNA damage induced in autologous human lymphocytes, assessed with the fluorometric analysis of DNA unwinding (FADU). Sonication of human serum generated significant DNA damage in autologous lymphocytes (DNA unwinding averaged 31.79% +/- 2.1 after sonication vs. 12.82% +/- 2.6 in the controls, p < 0.005). Superoxide dismutase (SOD; 500 I.U./ml), catalase (500 I.U./ml), mannitol (50 mM), and glutathione (50 mM) completely prevented DNA damage when added before serum sonication, whereas only mannitol (86%) and glutathione (90%) almost completely inhibited DNA damage when added after sonication. SOD and catalase had only a partial inhibitory effect when added after sonication (49% and 63%, respectively). The prevention of DNA damage was also obtained by an association of subliminal amounts of glutathione (20 mM) and vitamin E (1 I.U./ml). These results suggest that the clastogenic activity generated by sonication of human serum is mediated by oxygen radicals.
致断裂因子（CF）是能够损伤DNA的可扩散分子。它们由多种物理和化学刺激在生物介质中产生。其性质和作用机制在很大程度上仍然未知。通过对人血清进行脉冲超声处理可实验性地产生致断裂活性。为了研究氧自由基是否参与人血清超声处理诱导的致断裂活性，我们检测了在超声处理前后添加到人血清中的不同氧自由基清除剂对这种致断裂活性的影响。通过脉冲超声在24微瓦/平方厘米的条件下将人血清超声处理50分钟。通过测量自体人淋巴细胞中诱导的DNA损伤量，利用DNA解旋荧光分析（FADU）评估，在有或无氧自由基清除剂存在的情况下检测超声处理后人血清的致断裂活性。人血清的超声处理在自体淋巴细胞中产生了显著的DNA损伤（超声处理后DNA解旋平均为31.79%±2.1，而对照组为12.82%±2.6，p<0.005）。超氧化物歧化酶（SOD；500国际单位/毫升）、过氧化氢酶（500国际单位/毫升）、甘露醇（50毫摩尔）和谷胱甘肽（50毫摩尔）在血清超声处理前添加时可完全防止DNA损伤，而在超声处理后添加时，只有甘露醇（86%）和谷胱甘肽（90%）几乎完全抑制DNA损伤。SOD和过氧化氢酶在超声处理后添加时只有部分抑制作用（分别为49%和63%）。通过将阈下量的谷胱甘肽（20毫摩尔）和维生素E（1国际单位/毫升）联合使用也可防止DNA损伤。这些结果表明，人血清超声处理产生的致断裂活性是由氧自由基介导的。
