电离辐射对Jurkat T细胞周期进程的影响

Effect of ionizing radiation on cell cycle progression of Jurkat T cells

目的：探讨电离辐射诱导Jurkat T细胞损伤过程中细胞周期进程的变化规律。方法：采用流式细胞术（FCM）检测低剂量（0.075 Gy）和较大剂量（0.5、1.0、2.0、4.0及6.0 Gy）X射线照射后Jurkat T细胞周期进程变化的时间-效应关系和剂量-效应关系。结果：时间-效应关系研究发现，2.0 Gy X射线照射后JurkatT细胞相继发生S期延迟和G2期阻滞，S期细胞百分率于照射后立即增加（P〈0.001），而G2＋M期细胞百分率照射后8 h开始显著增加（P〈0.001）。剂量-效应关系研究发现，75 mGy低剂量X射线照射即可诱导JurkatT细胞发生S期延迟（P〈0.001）和G2期阻滞（P〈0.05）；0.5-6.0 Gy较大剂量X射线照射后，Jurkat T细胞发生S期延迟和G2期阻滞。与假照组相比较，G0/G1期细胞百分率显著降低（P〈0.001），在0.5-6.0 Gy内具有剂量依赖性，而S期和G2＋M期细胞百分率显著升高（P〈0.05或P〈0.001）。结论：X射线照射可以改变Jurkat T细胞周期进程，诱导其相继发生S期延迟和G2期阻滞，在0.5-6.0 Gy内具有剂量依赖性。

Objective To investigate the change regularity of cell cycle progression in Jurkat T cells damaged by ionizing radiation. Methods The time- and dose-effects of cell cycle progression in Jurkat T cells after X-irradiation with different doses （0. 075, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy） were detected with flow cytometry. Results For the time-effect, the percentage of Jurkat T cells in S phase immediately increased after irradiation with 2.0 Gy X-rays, and that of G2 ＋ M phase cells increased significantly 8 h after irradiation as compared with that in the sham irradiation （P〈 0. 001）. For the dose-effect, the percentage of G0/G1 phase cells 18 h after irradiation with 0. 075 Gy and 0.5- 6.0 Gy was significantly lower than that in the sham-irradiation in a dose-dependent pattern （P〈0. 001）, while the percentages of S and G2-F M phase cells increased significantly （P〈 0. 001）. Conclusion Ionizing radiation with 0.5-6.0 Gy X-rays could induce S delay and G2 arrest in Jurkat T cells in a dose-dependent pattern.