Chung J H, Koh W S, Youn J I
Department of Dermatology, Seoul National University, College of Medicine, Korea.
Lasers Surg Med. 1996;18(4):358-66. doi: 10.1002/(SICI)1096-9101(1996)18:4<358::AID-LSM4>3.0.CO;2-R.
The object of this study is to characterize the effects of epidermal melanin in brown skin on selective vessel damage by copper vapor laser radiation in port wine stain (PWS). STUDY DESIGN/MATERIALS, AND METHODS: We observed the histological changes of PWS in Korean patients who received copper vapor laser (578 nm) treatment over a range of energy densities (6-14 J/cm2) and exposure durations (30-200 ms). The nitroblue tetrazolium chloride (NBTC) staining method was used to differentiate between the blue-stained viable cells and the unstained thermally damaged cells.
With Fontana-Masson stain, we found that Korean skin has more epidermal melanin than Caucasian skin. For energy densities greater than 6 J/cm2, epidermal damage was observed. At 6 and 8 J/cm2, the damage to the dermis was localized to the blood vessels and the perivascular tissue. The connective tissue between damaged vessels and epidermis was still viable. Energy densities above 10 J/cm2 produced a diffuse thermal necrosis. We conclude that vascular selectivity without epidermal damages cannot be achieved with a 50 ms exposure at 578 nm in the brown skin of Koreans. The energy density for clinical minimal whitening was 6-8 J/cm2, and the maximum penetration depth of these energy densities was 0.4 mm. We also found that the epidermal damage increased with increasing pulse widths at a fixed energy density (10 or 8 J/cm2) while the severity and depth of vascular damage decreased. These findings suggest that it is best to treat PWS with a copper vapor laser at the minimal pulse width and maximal power output possible at given energy density.
We have demonstrated that the copper vapor laser treatment of PWS in the brown skin is not as selective as in white skin because of epidermal melanin.
本研究的目的是描述棕色皮肤中表皮黑色素对铜蒸气激光辐射治疗葡萄酒色斑（PWS）时选择性血管损伤的影响。
研究设计/材料与方法：我们观察了接受铜蒸气激光（578nm）治疗的韩国患者PWS的组织学变化，治疗能量密度范围为6-14J/cm²，曝光持续时间为30-200ms。采用氯化硝基四氮唑蓝（NBTC）染色法区分染成蓝色的活细胞和未染色的热损伤细胞。
通过Fontana-Masson染色，我们发现韩国人的皮肤比白种人的皮肤含有更多的表皮黑色素。当能量密度大于6J/cm²时，观察到表皮损伤。在6和8J/cm²时，真皮损伤局限于血管和血管周围组织。受损血管与表皮之间的结缔组织仍然存活。能量密度高于10J/cm²会产生弥漫性热坏死。我们得出结论，在韩国人的棕色皮肤中，578nm波长、50ms曝光时间无法实现无表皮损伤的血管选择性。临床最小美白的能量密度为6-8J/cm²，这些能量密度的最大穿透深度为0.4mm。我们还发现，在固定能量密度（10或8J/cm²）下，表皮损伤随脉冲宽度增加而增加，而血管损伤的严重程度和深度则降低。这些发现表明，在给定能量密度下，用铜蒸气激光治疗PWS时，最好采用尽可能小的脉冲宽度和最大的功率输出。
我们已经证明，由于表皮黑色素的存在，铜蒸气激光治疗棕色皮肤的PWS不如治疗白色皮肤那样具有选择性。
