De Leeuw S M, Smit N P, Van Veldhoven M, Pennings E M, Pavel S, Simons J W, Schothorst A A
Department of Dermatology, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands.
J Photochem Photobiol B. 2001 Aug 30;61(3):106-13. doi: 10.1016/s1011-1344(01)00168-3.
Cultured melanocytes originating from persons with different skin phototypes were utilized for measurement of endonuclease sensitive sites induced by UVB and the determination of cell survival after UVA or UVB irradiation. During culture, the melanocytes largely maintained their phenotypic characteristics according to their original skin phototype. Total melanin concentrations were 4.9 times higher in the darker skin phototype (IV-VI) melanocytes when compared to the cells from lighter skin phototypes (I-III). Also phaeomelanin contents were higher (2.5 times) in the skin phototype (IV-VI) melanocytes which implies that the cells from light skin types contain less melanin, but a relatively high proportion of phaeomelanin. After UVB irradiation a stronger induction of endonuclease sensitive sites was found for melanocytes with a lower level of total melanin and a high content of pheomelanin. By measuring the clone forming ability in different melanocyte cultures after UVB irradiation, significant better survival was found in case of the cells with the higher melanin content. Despite the large variations in melanin content, no significant difference in survival after UVA irradiation could be demonstrated in this way. Our results suggest a protective effect of melanin for UVB and indicate the importance of the measurements of melanin content and composition when different parameters of UV-induced damage are studied in melanin producing cells.
来自不同皮肤光类型人群的培养黑素细胞被用于测量UVB诱导的核酸酶敏感位点以及UVA或UVB照射后细胞存活率的测定。在培养过程中，黑素细胞在很大程度上根据其原始皮肤光类型维持其表型特征。与来自较浅皮肤光类型（I-III）的细胞相比，较深皮肤光类型（IV-VI）的黑素细胞中总黑色素浓度高4.9倍。此外，皮肤光类型（IV-VI）的黑素细胞中褐黑素含量也更高（2.5倍），这意味着来自浅肤色类型的细胞含有较少的黑色素，但褐黑素比例相对较高。UVB照射后，发现总黑色素水平较低且褐黑素含量高的黑素细胞对核酸酶敏感位点的诱导更强。通过测量UVB照射后不同黑素细胞培养物中的克隆形成能力，发现黑色素含量较高的细胞存活率明显更好。尽管黑色素含量存在很大差异，但通过这种方式未发现UVA照射后存活率有显著差异。我们的结果表明黑色素对UVB有保护作用，并表明在研究产生黑色素的细胞中UV诱导损伤的不同参数时，测量黑色素含量和组成的重要性。
