Neumann R A, Knobler R M, Leonhartsberger H, Gebhart W
Department of Dermatology II, University of Vienna School of Medicine, Austria.
J Invest Dermatol. 1992 Aug;99(2):160-7. doi: 10.1111/1523-1747.ep12616789.
The present study compared the histologic changes occurring 15 min after copper vapor laser (CVL; operating at 578 nm) and argon laser (488/514 nm) treatment of port-wine stains (PWS) over a range of energy densities (8-32 J/cm2) with corresponding pulse widths of 50-200 ms. Frozen tissue sections were stained with nitroblue tetrazolium chloride (NBTC). This histochemical method permits an accurate color differentiation between blue-stained viable and unstained thermally damaged cells. At 8, 10, and 12 J/cm2 the argon-laser injury was confined to epidermal cell layers; none to superficial dermal effects were found. Fluences of at least 15 J/cm2 produced a diffuse NBTC-negative coagulation necrosis. Exposure of PWS skin to 8-12 J/cm2 at 578 nm did not alter the integrity of epidermal cells. In the dermis, damage was confined to blood vessels and surrounding collagen, showing a clear demarcation from adjacent viable structures. The maximum penetration depth achieved with these vessel selective energy densities was 0.44 mm. At 15 J/cm2, besides vascular injury, damage to the basal cell layer also occurred. At fluences of 17-20 J/cm2 a diffuse necrosis similar to that induced by the argon laser was found. Vessel selectivity of the 578 nm wave band was achieved with pulse widths from 50-74 ms, exceeding the estimated "ideal" exposure time (0.1-10.0 ms) for a vascular selective laser effect. The NBTC method allowed identification of subtle laser-induced tissue changes providing accurate quantitative data relating to the extent of vascular injury.
本研究比较了铜蒸气激光（CVL；波长578nm）和氩激光（488/514nm）在一系列能量密度（8 - 32J/cm²）及相应脉冲宽度50 - 200ms下治疗鲜红斑痣（PWS）15分钟后发生的组织学变化。冷冻组织切片用氯化硝基四氮唑蓝（NBTC）染色。这种组织化学方法能准确区分染成蓝色的存活细胞和未染色的热损伤细胞。在8、10和12J/cm²时，氩激光损伤局限于表皮细胞层；未发现对真皮浅层有影响。至少15J/cm²的能量密度会产生弥漫性NBTC阴性凝固性坏死。鲜红斑痣皮肤在578nm波长下接受8 - 12J/cm²照射时，表皮细胞完整性未改变。在真皮层，损伤局限于血管及周围胶原蛋白，与相邻的存活结构有明显界限。这些血管选择性能量密度所能达到的最大穿透深度为0.44mm。在15J/cm²时，除血管损伤外，基底细胞层也出现损伤。在17 - 20J/cm²的能量密度下，发现了与氩激光诱导的类似弥漫性坏死。578nm波段的血管选择性在50 - 74ms的脉冲宽度下实现，超过了血管选择性激光效应的估计“理想”暴露时间（0.1 - 10.0ms）。NBTC方法能够识别激光诱导的细微组织变化，提供与血管损伤程度相关的准确定量数据。
