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为了解环境理化因子作用对机体产生的生物效应 ,采用3 H TdR掺入法研究了甲基汞和不同剂量的电离辐射对小鼠胸腺DNA合成及适应性反应的影响。结果表明 :甲基汞可以抑制胸腺细胞DNA合成 ;低剂量的电离辐射 ( 0 0 75Gy)对胸腺DNA合成具有一定刺激作用 ,3 H TdR掺入量明显高于对照组 ;而高剂量的电离辐射 ( 2Gy)对胸腺细胞DNA合成有抑制作用 ;经低剂量电离辐射预处理后再进行甲基汞染毒时比单独用甲基汞染毒组的损伤减轻 ,3 H TdR掺入量增加 ;先给予高剂量电离辐射再进行甲基汞染毒比单独用甲基汞染毒组胸腺细胞3 H TdR掺入量明显下降。提示低剂量电离辐射可以产生兴奋刺激作用 ,对DNA损伤产生保护作用。其机理有待于进一步研究。
To understand the biological effects of environmental physico-chemical factors on the organism, 3 H TdR incorporation method was used to study the effects of methylmercury and different doses of ionizing radiation on thymus DNA synthesis and adaptive responses in mice. The results showed that methylmercury could inhibit thymocyte DNA synthesis. Low doses of ionizing radiation (0 0 75 Gy) stimulated thymus DNA synthesis, and 3 H TdR incorporation was significantly higher than that of the control group. However, high doses of ionizing radiation (2Gy) inhibited the DNA synthesis of thymocytes; when methylmercury was pretreated with low dose ionizing radiation, the injury of methylmercury exposure group was lessened and the amount of 3 H TdR incorporation was increased; Methylmercury exposure to high doses of ionizing radiation was significantly less than that of thymus cells exposed to methylmercury alone. Tip low-dose ionizing radiation can produce excitatory stimuli, have a protective effect on DNA damage. The mechanism needs further study.