Cario-André Muriel, Briganti Stefania, Picardo Mauro, Nikaido Osamu, de Verneuil Hubert, Taïeb Alain
INSERM E0217, Université Victor Segalen Bordeaux II, 146 rue Leo Saignat, 33076 Bordeaux cedex, France.
Exp Dermatol. 2005 Mar;14(3):194-201. doi: 10.1111/j.0906-6705.2005.00273.x.
The incidence rate of melanoma is higher in fair-skinned than in dark-skinned individuals. In negroid skin there is more eumelanin which is present in all skin layers and fewer polyunsaturated fatty acids (PUFA) than in caucasoid skin. The western diet, which is rich in omega-6 polyunsaturated fatty acids, is associated with more proneness to cancer including cutaneous melanoma. To study the respective influence of omega-6 PUFA and low phototype melanocytes on redox status -basal and following UV irradiation-, we used epidermal reconstructs. The addition of polyunsaturated fatty acids as well as the presence of low phototype melanocytes affected basal status similarly except for catalase activity, which decreased significantly in polyunsaturated fatty acid-supplemented reconstructs. Following UV, polyunsaturated fatty acids and low phototype melanocytes increased lipid and protein oxidative damage without affecting direct DNA damage. However, polyunsaturated fatty acids increased epidermal apoptosis whereas low phototype melanocytes decreased it. Since our data suggest that an omega-6 PUFA rich-diet may increase oxidative damage in melanocytes without inducing apoptosis, the long-term net outcome could be cumulated mutations and an increased risk of skin cancer, especially melanoma.
黑色素瘤的发病率在白皮肤个体中高于黑皮肤个体。在黑人皮肤中，所有皮肤层中存在的真黑素更多，且与高加索人种皮肤相比，多不饱和脂肪酸（PUFA）更少。富含ω-6多不饱和脂肪酸的西方饮食与包括皮肤黑色素瘤在内的更多癌症易感性相关。为了研究ω-6多不饱和脂肪酸和低光型黑素细胞对氧化还原状态（基础状态和紫外线照射后）的各自影响，我们使用了表皮重建物。除过氧化氢酶活性外，多不饱和脂肪酸的添加以及低光型黑素细胞的存在对基础状态的影响相似，在补充多不饱和脂肪酸的重建物中过氧化氢酶活性显著降低。紫外线照射后，多不饱和脂肪酸和低光型黑素细胞增加了脂质和蛋白质氧化损伤，而不影响直接DNA损伤。然而，多不饱和脂肪酸增加了表皮细胞凋亡，而低光型黑素细胞则降低了凋亡。由于我们的数据表明富含ω-6多不饱和脂肪酸的饮食可能增加黑素细胞中的氧化损伤而不诱导凋亡，长期的净结果可能是累积突变和皮肤癌尤其是黑色素瘤风险增加。
