Supranuclear melanin caps reduce ultraviolet induced DNA photoproducts in human epidermis
Supranuclear melanin caps reduce ultraviolet induced DNA photoproducts in human epidermis
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DOI：
10.1046/j.1523-1747.1998.00178.x
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发表时间：
1998-05-01
影响因子：
6.5
通讯作者：
Mori, T
中科院分区：
文献类型：
--
作者：
Kobayashi, N;Nakagawa, A;Mori, T
黑色素可以在人表皮中形成核上帽，这表明细胞内黑色素可以减少紫外线传输到下层细胞核，并抑制紫外线诱导的DNA光产物的形成。本研究的目的是确定表皮黑色素的光保护作用。我们用紫外线B照射正常的人皮肤外植体，并通过间接免疫荧光和使用环丁烷二聚体或（6-4）光产物特异性单克隆抗体的激光细胞术测定了单个表皮细胞中环丁烷嘧啶二聚体和（6-4）光产物的形成。我们发现，具有核上黑色素帽的表皮细胞的DNA光产物（两种类型）明显少于没有核上黑色素帽的表皮细胞。此外，抗两种类型的光斑的保护因子与表皮细胞中的黑色素浓度相关。这些结果表明，黑色素以浓度依赖的方式减少人表皮紫外线诱导的DNA光产物。
Melanin can form supranuclear caps in human epidermis, suggesting that intracellular melanin reduces ultraviolet transmission to underlying cell nuclei and inhibits the formation of ultraviolet induced DNA photoproducts. The purpose of this study was to determine the photoprotective effect of epidermal melanin. We irradiated normal human skin explants with ultraviolet B and determined the formation of cyclobutane pyrimidine dimers and (6-4)photoproducts in individual epidermal cells by indirect immunofluorescence and by laser cytometry using monoclonal antibodies specific for cyclobutane dimers or for (6-4)photoproducts, We found that epidermal cells with supranuclear melanin caps had significantly less DNA photoproducts (both types) than epidermal cells without supranuclear melanin caps. Moreover, the protection factor against both types of photolesions correlated with melanin concentration in epidermal cells. These results indicate that melanin reduces ultraviolet induced DNA photoproducts in human epidermis in a concentration dependent manner.