Andersson M, Stenqvist P, Hellman B
Department of Pharmaceutical Biosciences, Division of Toxicology, Uppsala University, Sweden.
Cell Biol Toxicol. 2007 Nov;23(6):401-11. doi: 10.1007/s10565-007-9002-5. Epub 2007 Apr 11.
It has been suggested that extended-term cultures of human lymphocytes could be used as a complement to cell lines based on transformed cells when testing the genotoxicity of chemicals. To investigate whether the pattern of induced DNA damage and its subsequent repair differs significantly between cultures based on different blood donors, hydrogen peroxide (H(2)O(2))-induced DNA damage was measured in cultures from four different subjects using the comet assay. The DNA damage was significantly increased in all cultures after 10 min exposure to 0.25 mmol/L H(2)O(2), and there was a significant decrease in the H(2)O(2)-induced DNA damage in all cultures after 30 min of DNA repair. The level of damage varied between the different donors, especially after the repair. Using PCR and DNA sequencing, exon 5 of the p53 gene was sequenced in the lymphocytes from the donors with the lowest and highest residual damage. No such mutation was found. Mouse lymphoma L5178Y cells carrying the p53 mutation in exon 5 were included as a reference. These cells were found to be less sensitive toward the H(2)O(2)-induced DNA damage, and they were also found to have a rather low DNA repair capacity. The demonstrated variation in H(2)O(2)-induced DNA damage and DNA repair capacity between the cultures from the different subjects may be important from a risk assessment perspective, but is obviously not of decisive importance when it comes to the development of a routine assay for genotoxicity.
有人提出，在测试化学品的遗传毒性时，人类淋巴细胞的长期培养物可作为基于转化细胞的细胞系的补充。为了研究基于不同献血者的培养物之间诱导的DNA损伤模式及其后续修复是否存在显著差异，使用彗星试验在来自四个不同受试者的培养物中测量了过氧化氢（H₂O₂）诱导的DNA损伤。在暴露于0.25 mmol/L H₂O₂ 10分钟后，所有培养物中的DNA损伤均显著增加，并且在DNA修复30分钟后，所有培养物中H₂O₂诱导的DNA损伤均显著降低。不同献血者之间的损伤水平有所不同，尤其是在修复后。使用PCR和DNA测序，对残留损伤最低和最高的献血者的淋巴细胞中的p53基因外显子5进行了测序。未发现此类突变。将携带外显子5中p53突变的小鼠淋巴瘤L5178Y细胞作为对照。发现这些细胞对H₂O₂诱导的DNA损伤不太敏感，并且还发现它们的DNA修复能力相当低。从风险评估的角度来看，不同受试者的培养物之间所证明的H₂O₂诱导的DNA损伤和DNA修复能力的差异可能很重要，但在开发常规遗传毒性试验时显然不是决定性的。
