Faculty of Health Sciences, Hokkaido University, Kita-12 Nishi-5, Kita-ku, Sapporo, 060-0812, Japan.
Research Group for Radiation Transport Analysis, Nuclear Science and Engineering Center, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata, Tokai, Ibaraki, 319-1195, Japan.
Sci Rep. 2024 May 28;14(1):12160. doi: 10.1038/s41598-024-62679-8.
The knowledge on responses of human lens epithelial cells (HLECs) to ionizing radiation exposure is important to understand mechanisms of radiation cataracts that are of concern in the field of radiation protection and radiation therapy. However, biological effects in HLECs following protracted exposure have not yet fully been explored. Here, we investigated the temporal kinetics of γ-H2AX foci as a marker for DNA double-strand breaks (DSBs) and cell survival in HLECs after exposure to photon beams at various dose rates (i.e., 150 kVp X-rays at 1.82, 0.1, and 0.033 Gy/min, and Cs γ-rays at 0.00461 Gy/min (27.7 cGy/h) and 0.00081 Gy/min (4.9 cGy/h)), compared to those in human lung fibroblasts (WI-38). In parallel, we quantified the recovery for DSBs and cell survival using a biophysical model. The study revealed that HLECs have a lower DSB repair rate than WI-38 cells. There is no significant impact of dose rate on cell survival in both cell lines in the dose-rate range of 0.033-1.82 Gy/min. In contrast, the experimental residual γ-H2AX foci showed inverse dose rate effects (IDREs) compared to the model prediction, highlighting the importance of the IDREs in evaluating radiation effects on the ocular lens.
人类晶状体上皮细胞 (HLECs) 对电离辐射暴露的反应的知识对于理解辐射性白内障的机制很重要，而辐射性白内障是辐射防护和放射治疗领域关注的问题。然而，HLECs 中持续暴露后的生物学效应尚未得到充分探索。在这里，我们研究了在不同剂量率（即 150 kVp X 射线 1.82、0.1 和 0.033 Gy/min，以及 Cs γ 射线 0.00461 Gy/min（27.7 cGy/h）和 0.00081 Gy/min（4.9 cGy/h））照射后，HLECs 中 γ-H2AX 焦点作为 DNA 双链断裂 (DSB) 标志物和细胞存活的时间动力学，与人类肺成纤维细胞 (WI-38) 进行了比较。同时，我们使用生物物理模型定量评估 DSB 修复和细胞存活的恢复情况。研究表明，HLECs 的 DSB 修复率低于 WI-38 细胞。在 0.033-1.82 Gy/min 的剂量率范围内，两种细胞系的细胞存活均不受剂量率的显著影响。相比之下，实验残留的 γ-H2AX 焦点与模型预测相比表现出相反的剂量率效应 (IDRE)，这突出了在评估辐射对眼部晶状体的影响时考虑 IDRE 的重要性。
