de Laat A, van Tilburg M, van der Leun J C, van Vloten W A, de Gruijl F R
Department of Dermatology, Utrecht University, Netherlands.
Photochem Photobiol. 1996 Apr;63(4):492-7. doi: 10.1111/j.1751-1097.1996.tb03075.x.
There is limited information about the carcinogenic effect of longwave ultraviolet radiation (UVA: 315-400 nm). In particular very little is known about the relevant genotoxic damage caused by physiological doses of UVA radiation. A general response of cells to DNA damage is a delay or arrest of the cell cycle. Conversely, such cellular responses after UVA irradiation would indicate significant genotoxic damage. The aim of this study is to compare cell cycle kinetics of human fibroblasts after UVC (190-280 nm radiation), UVB (280-315 nm radiation) and UVA irradiation. Changes in the cell cycle kinetics were assessed by bivariate flow cytometric analysis of DNA synthesis and of DNA content. After UVC, UVB or UVA irradiation of human fibroblasts a suppression was seen of bromodeoxyuridine (BrdU) incorporation at all stages of S phase. The magnitude of this suppression appeared dose dependent. Maximum suppression was reached at 5-7 h after UVB exposure and directly after UVA exposure, and normal levels were reached 25 h after UVB and 7 h after UVA exposure. The lowered BrdU uptake corresponded with a lengthening of the S phase. No dramatic changes in percentages of cells in G1, S and G2/M were seen after the various UV irradiations. Apparently, UVA irradiation, like UVB and UVC irradiation, can temporarily inhibit DNA synthesis, which is indicative of genotoxic damage.
关于长波紫外线辐射（UVA：315 - 400纳米）的致癌作用，目前的信息有限。特别是对于生理剂量的UVA辐射所造成的相关遗传毒性损伤，人们了解得非常少。细胞对DNA损伤的一般反应是细胞周期延迟或停滞。相反，UVA照射后的这种细胞反应将表明存在显著的遗传毒性损伤。本研究的目的是比较人成纤维细胞在接受UVC（190 - 280纳米辐射）、UVB（280 - 315纳米辐射）和UVA照射后的细胞周期动力学。通过对DNA合成和DNA含量进行双变量流式细胞术分析来评估细胞周期动力学的变化。在人成纤维细胞接受UVC、UVB或UVA照射后，在S期的所有阶段均可见溴脱氧尿苷（BrdU）掺入受到抑制。这种抑制的程度似乎呈剂量依赖性。UVB照射后5 - 7小时以及UVA照射后立即达到最大抑制，UVB照射后25小时和UVA照射后7小时恢复到正常水平。BrdU摄取的降低与S期的延长相对应。在各种紫外线照射后，G1、S和G2/M期细胞的百分比未见显著变化。显然，UVA照射与UVB和UVC照射一样，可暂时抑制DNA合成，这表明存在遗传毒性损伤。
