Held K D, Awad S
Department of Radiation Medicine, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Int J Radiat Biol. 1991 Mar;59(3):699-710. doi: 10.1080/09553009114550611.
The effects of polyamines on the loss of biological activity of bacterial transforming DNA irradiated in the absence and presence of sulphydryl-containing compounds has been investigated. In both oxygenated and hypoxic conditions the polyamines (spermine, spermidine, putrescine and cadaverine) are radioprotectors with the degree of protection increasing with increasing polyamine concentration. When O2-saturated DNA solutions are irradiated, the degree of radioprotection by polyamines generally correlates with the efficiency of scavenging of OH. radicals. In N2 the protection does not show that correlation; several possible reasons are discussed. With the exception of spermine, the polyamines are slightly more protective of oxygenated DNA than of hypoxic DNA. When DNA is irradiated in the presence of both polyamines and thiols, the combined protection is usually greater than that exhibited by either agent alone. When irradiation is in oxygen, the combined agents appear to operate by the same mechanism, namely OH. radical scavenging. In N2-saturated solutions, polyamines and dithiothreitol appear to act by different, non-interacting mechanisms; however WR1065 and polyamines may radioprotect by the same mechanism. Also, the results suggest that polyamines may reduce the ability of some thiols to radioprotect DNA.
研究了多胺对在有无含巯基化合物存在下辐照的细菌转化DNA生物活性丧失的影响。在有氧和缺氧条件下，多胺（精胺、亚精胺、腐胺和尸胺）都是辐射防护剂，其防护程度随多胺浓度的增加而提高。当用氧气饱和的DNA溶液进行辐照时，多胺的辐射防护程度通常与羟基自由基清除效率相关。在氮气中，这种防护作用并不呈现这种相关性；文中讨论了几种可能的原因。除精胺外，多胺对有氧DNA的保护作用略强于对缺氧DNA的保护作用。当DNA在多胺和硫醇同时存在的情况下进行辐照时，联合防护作用通常大于单独使用任何一种试剂时的防护作用。当在氧气中进行辐照时，联合试剂似乎通过相同的机制起作用，即清除羟基自由基。在氮气饱和溶液中，多胺和二硫苏糖醇似乎通过不同的、不相互作用的机制起作用；然而，WR1065和多胺可能通过相同的机制进行辐射防护。此外，结果表明多胺可能会降低某些硫醇对DNA的辐射防护能力。
