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本实验目的是研究二甲基亚硝胺对 DNA 的损伤而产生6位甲基化鸟嘌呤(O~6mGua)及7位甲基化鸟嘌呤(m~7Gua)所起的作用。在饮水中加入二甲基亚硝胺(DMN),浓度为10PPm,用以喂饲小鼠,平均剂量为2mg/kg/天。并于第1、2、4、8、16及32天处死小鼠,取肝、肺组织提取 DNA。DNA 水解后,用带荧光检测器的高效液相色谱仪检测嘌呤基。结果表明:肝、肺均可检出O~6mGua、m~7Gua,而 O~6mGua 在开始接触 DMN 的1～2天内,浓度迅速衰减,在32天时又有所增加,可见体内有修复 DNA 的能力,但长期连续接触 DMN,则O~6mGua 可积累在 DNA 中,可能导致肿瘤的发生。
The aim of this study was to investigate the effect of dimethylnitrosamine on the DNA damage induced by 6-methylated guanine (O ~ 6mGua) and 7-methylated guanine (m ~ 7Gua). Dimethylnitrosamine (DMN) was added to the drinking water at a concentration of 10 ppm for the mice to be fed at an average dose of 2 mg / kg / day. Mice were sacrificed on days 1, 2, 4, 8, 16 and 32, and DNA was extracted from liver and lung tissues. After DNA hydrolysis, purine groups were detected using a high-performance liquid chromatograph with a fluorescence detector. The results showed that O ~ 6mGua and m ~ 7Gua could be detected in both liver and lung, while the concentration of O ~ 6mGua decreased rapidly within 1 ~ 2 days after DMN exposure, and increased again after 32 days. Ability, but long-term continuous exposure to DMN, O ~ 6mGua can accumulate in the DNA, may lead to the occurrence of tumors.