Mun Ji Young, Jeong Se Yeong, Kim Jae Hwan, Han Sung Sik, Kim Il-Hwan
School of Life Sciences and Biotechnology, Korea University, Anamdong, Seongbukgu, Seoul 136-701, South Korea.
J Electron Microsc (Tokyo). 2011;60(1):11-8. doi: 10.1093/jmicro/dfq068. Epub 2010 Oct 11.
Laser treatment using low fluence for melasma was previously introduced to overcome postinflammatory hypermelanosis after Q-switched laser therapy. However, research on the mechanism of this treatment is very limited. In this study, a collimated low fluence 1064 nm Q-switched Nd:YAG laser with a pulse width of <7 ns was applied using top-hat beam mode. The aim of this study was to investigate the mode of action of this laser treatment through electron microscopy. The effectiveness of this treatment was confirmed by clinical photos, melasma area and severity index and spectrophotometer. To understand the mode of action, the three-dimensional structure of melanocytes in the epidermis was analyzed using serial images acquired by a 3VIEW surface block face scanning electron microscope. In the epidermis, after laser treatment, fewer dendrites in the melanocytes were observed compared with pretreatment. In addition, ultrastructural changes in the melanosome were studied using transmission electron microscopy, which showed that laser treatment caused selective photothermolysis on Stage IV melanosome. Therefore, this treatment should be regarded as an effective method for treating melasma through subcellular-selective photothermolysis.
先前曾引入使用低能量密度的激光治疗黄褐斑，以克服调Q激光治疗后的炎症后色素沉着过度。然而，关于这种治疗机制的研究非常有限。在本研究中，使用平顶光束模式应用了脉冲宽度小于7纳秒的准直低能量密度1064纳米调Q钕:钇铝石榴石激光。本研究的目的是通过电子显微镜研究这种激光治疗的作用方式。通过临床照片、黄褐斑面积和严重程度指数以及分光光度计证实了这种治疗的有效性。为了解其作用方式，使用3VIEW表面块面扫描电子显微镜获取的系列图像分析了表皮中黑素细胞的三维结构。在表皮中，激光治疗后，与治疗前相比，观察到黑素细胞中的树突减少。此外，使用透射电子显微镜研究了黑素小体的超微结构变化，结果表明激光治疗对IV期黑素小体产生了选择性光热解作用。因此，这种治疗应被视为一种通过亚细胞选择性光热解治疗黄褐斑的有效方法。
