Nam Jae-Hui, Min Joon Hong, Kim Wang-Kyun, Yim Sunmin, Kim Won-Serk
Department of Dermatology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Lasers Med Sci. 2017 Jul;32(5):1063-1069. doi: 10.1007/s10103-017-2208-8. Epub 2017 Apr 20.
A low-fluence 1064-nm Q-switched neodymium-doped yttrium aluminum garnet laser, or laser toning, has yielded favorable outcomes in various benign pigmented disorders. However, the exact mechanism of action of laser toning has not been fully elucidated. We sought to determine the inhibitory effect of laser toning on melanogenesis and to assess how laser passes influence the outcomes. To produce perceptible pigmentation, nine HRM-2 melanin-possessing hairless mice were treated with ultraviolet (UV) B radiation on the dorsal skin. This was followed by zero, two, four, or six passes of laser toning twice in 2 weeks on each designated quadrant. The spectrophotometric values and pigmentation-related protein expressions were measured. Pigment changes were found in the mice skin using the Fontana-Masson stain for histopathological analysis. Four- and six-pass laser toning significantly improved the lightness compared to that in the unirradiated control (p < 0.002). The Fontana-Masson stain showed that melanin was considerably decreased in laser-irradiated skin. As the number of laser passes increased, the expression of tyrosinase decreased (p < 0.008). The following parameters also decreased in proportion to the number of laser passes: MITF, TRP-1, TRP-2, p-ERK, and p-Akt. In contrast, TGF-β increased in proportion to the number of laser passes. However, the changes in these six proteins were not statistically significant. Our study demonstrates that laser toning improves skin pigmentation with increased number of passes in a dose-dependent manner. This effect is mediated by tyrosinase inhibition.
低能量1064纳米调Q掺钕钇铝石榴石激光，即激光美肤，已在多种良性色素沉着疾病中取得了良好效果。然而，激光美肤的确切作用机制尚未完全阐明。我们试图确定激光美肤对黑素生成的抑制作用，并评估激光照射次数如何影响效果。为了产生可察觉的色素沉着，对9只拥有HRM - 2黑色素的无毛小鼠背部皮肤进行紫外线B辐射处理。随后，在2周内对每个指定象限进行零次、两次、四次或六次激光美肤照射，每次照射两次。测量分光光度值和与色素沉着相关的蛋白质表达。使用Fontana - Masson染色法对小鼠皮肤进行组织病理学分析，以观察色素变化。与未照射的对照组相比，四次和六次激光美肤显著改善了皮肤亮度（p < 0.002）。Fontana - Masson染色显示，激光照射的皮肤中黑色素明显减少。随着激光照射次数的增加，酪氨酸酶的表达降低（p < 0.008）。以下参数也与激光照射次数成比例下降：小眼畸形相关转录因子（MITF）、酪氨酸酶相关蛋白1（TRP - 1）、酪氨酸酶相关蛋白2（TRP - 2）、磷酸化细胞外信号调节激酶（p - ERK）和磷酸化蛋白激酶B（p - Akt）。相反，转化生长因子 - β（TGF - β）与激光照射次数成比例增加。然而，这六种蛋白质的变化在统计学上并不显著。我们的研究表明，激光美肤以剂量依赖的方式随着照射次数的增加改善皮肤色素沉着。这种效果是由酪氨酸酶抑制介导的。
