Chen Heyu, Wang Ban, Wang Caixia, Cao Wei, Zhang Jie, Ma Yingxin, Hong Yunyi, Fu Shen, Wu Fan, Ying Weihai
School of Biomedical Engineering and Med-X Research Institute, Shanghai Jiao Tong University Shanghai, P. R. China.
Department of Radiation Oncology, Shanghai Proton and Heavy Ion Center, Fudan University Cancer Hospital Shanghai, P. R. China.
Int J Physiol Pathophysiol Pharmacol. 2016 Dec 25;8(4):140-145. eCollection 2016.
Synchrotron radiation (SR) X-ray has significant potential for applications in medical imaging and cancer treatment. However, the mechanisms underlying SR X-ray-induced tissue damage remain unclear. Previous studies on regular X-ray-induced tissue damage have suggested that dose-rate could affect radiation damage. Because SR X-ray has exceedingly high dose-rate compared to regular X-ray, it remains to be determined if dose-rate may affect SR X-ray-induced tissue damage. We used rodent testes as a model to investigate the role of dose-rate in SR X-ray-induced tissue damage. One day after SR X-ray irradiation, we determined the effects of the irradiation of the same dosage at two different dose-rates, 0.11 Gy/s and 1.1 Gy/s, on TUNEL signals, caspase-3 activation and DNA double-strand breaks (DSBs) of the testes. Compared to those produced by the irradiation at 0.11 Gy/s, irradiation at 1.1 Gy/s produced higher levels of DSBs, TUNEL signals, and caspase-3 activation in the testes. Our study has provided the first evidence suggesting that dose-rate could be a significant factor in SR X-ray-induced tissue damage, which may establish a valuable base for utilizing this factor to manipulate the tissue damage in SR X-ray-based medical applications.
同步辐射（SR）X射线在医学成像和癌症治疗方面具有巨大的应用潜力。然而，SR X射线诱导组织损伤的潜在机制仍不清楚。先前关于常规X射线诱导组织损伤的研究表明，剂量率可能会影响辐射损伤。由于与常规X射线相比，SR X射线具有极高的剂量率，因此剂量率是否会影响SR X射线诱导的组织损伤仍有待确定。我们以啮齿动物睾丸为模型，研究剂量率在SR X射线诱导组织损伤中的作用。在SR X射线照射一天后，我们确定了两种不同剂量率（0.11 Gy/s和1.1 Gy/s）下相同剂量照射对睾丸TUNEL信号、半胱天冬酶-3激活和DNA双链断裂（DSB）的影响。与0.11 Gy/s照射产生的结果相比，1.1 Gy/s照射在睾丸中产生了更高水平的DSB、TUNEL信号和半胱天冬酶-3激活。我们的研究首次提供了证据，表明剂量率可能是SR X射线诱导组织损伤的一个重要因素，这可能为在基于SR X射线的医学应用中利用这一因素来控制组织损伤奠定有价值的基础。
