Masuda Kazuhiko, Miyamoto Tomomi, Cho A-Ri, Agui Takashi
Center for Experimental Animal Science, Department of Gastroenterological Surgery, Nagoya City, Aichi 468-8601, Japan.
Jpn J Vet Res. 2006 Feb;53(3-4):141-8.
The LEC rat is reported to exhibit hypersensitivity to X-irradiation, deficiency in DNA double-strand break repair, and radio-resistant DNA synthesis. This character of the LEC rat has been thought to be due to abnormal G1 arrest in cells after X-irradiation. In this report, we re-investigated the effect of X-irradiation on the cell cycle in primary-cultured fibroblasts. Primary-cultured fibroblasts derived from LEC and BN rats were exposed to 4 Gy of X-ray and their cell cycle analysis was performed with a flow cytometer. Fibroblasts derived from both rats showed normal response of the cell cycle, indicating the arrest at both G1--and G2/M-phase and no difference in the cell cycle population between fibroblasts derived from both rats. In contrast, when the same analysis was performed using the cell line, L7 and W8, which had been established from the lung fibroblasts of LEC and control WKAH rats, respectively, by immortalizing with SV40 T-antigen, L7 cells but not W8 cells showed impaired G1 arrest and abnormal cell cycle. These results suggest that fibroblasts derived from LEC rats possess the normal cell cycle response after X-irradiation, if they are kept naive as not immortalized with SV40 T-antigen.
据报道，LEC大鼠对X射线照射表现出超敏反应，DNA双链断裂修复缺陷以及抗辐射DNA合成。LEC大鼠的这一特性被认为是由于X射线照射后细胞中异常的G1期阻滞所致。在本报告中，我们重新研究了X射线照射对原代培养成纤维细胞细胞周期的影响。将来自LEC和BN大鼠的原代培养成纤维细胞暴露于4 Gy的X射线下，并用流式细胞仪进行细胞周期分析。两种大鼠来源的成纤维细胞均显示出正常的细胞周期反应，表明在G1期和G2/M期均发生阻滞，且两种大鼠来源的成纤维细胞在细胞周期群体上没有差异。相比之下，当使用分别通过用SV40 T抗原永生化从LEC大鼠和对照WKAH大鼠的肺成纤维细胞建立的细胞系L7和W8进行相同分析时，L7细胞而非W8细胞显示出G1期阻滞受损和异常的细胞周期。这些结果表明，如果LEC大鼠来源的成纤维细胞未用SV40 T抗原永生化而保持原始状态，则在X射线照射后具有正常的细胞周期反应。
