【摘要】 目的 探讨烟酰胺对中波紫外线(UVB)致豚鼠皮肤色素沉着的抑制作用。方法 以亚红斑剂量UVB照射豚鼠背部10天建立皮肤无急性损伤色素沉着动物模型后，外涂基质和2.5%、5%、10%的烟酰胺4周，在此期间观察肤色改变和测定皮肤L值。涂药结束后取材，进行Masson-Fontana、冰冻切片Dopa染色和黑素细胞超微结构观察，观察黑素细胞数量、形态和功能的改变。结果 涂抹5%烟酰胺4周后，豚鼠皮肤变白，L值显著下降，多巴阳性黑素细胞数及黑素含量指数较对照组明显减少(P<0.05)。结论 5%烟酰胺对UVB诱导的色素沉着有明显的抑制，它主要是通过抑制黑素细胞的增殖和黑素细胞内黑素小体的合成而发挥作用。

    【关键词】 烟酰胺;色素沉着; 黑素细胞

    Inhibitory effect of nicotinamide on hyperpigmentation induced by UVB using a brown guinea pig model

    PAN Jian-ying, ZHANG Yu-bin, Muhammad·Patam,et al.

    Laboratory of Dermo-physiology and Toxicology, School of Public Health, Fudan University, Shanghai 200032, China

    【Abstract】 Objective To investigate the inhibitory effect of nicotinamide on hyperpigmentation induced by UVB. Methods After hyperpigmentation was induced by UVB radiation on the back of brown guinea pigs, substance, 2.5%,5% and 10% nicotinamide were applied on the exposed skin for 4 weeks respectively. During this process, the changes of skin coloration were observed with naked eyes and L value were measured. Then the biopsy specimens were taken from the treated skin, sections were prepared for special staining and TEM examination and the number of melanocytes and melanin content index(MCI) were determined. Results After the application of 5% nicotinamide for 4 weeks, lightening effect was obviously observed with naked eyes and the L value decreased significantly. Compared with the substance control, the number of Dopa positive melanocytes and melanin content index were all significantly reduced (P<0.05) in the treated skin with 5% nicotinamide. Conclusion 5% nicotinamide is effective in lightening the UVB-induced pigmentation of guinea pig skin. This effect may be related to the declined proliferation of melanocytes and the inhibition of melanin synthesis in melanocytes. ......