Fluorescence photobleaching of ALA-induced protoporphyrin IX during photodynamic therapy of normal hairless mouse skin: The effect of light dose and irradiance and the resulting biological effect
Fluorescence photobleaching of ALA-induced protoporphyrin IX during photodynamic therapy of normal hairless mouse skin: The effect of light dose and irradiance and the resulting biological effect
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DOI：
10.1111/j.1751-1097.1998.tb05177.x
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发表时间：
1998-01-01
影响因子：
3.3
通讯作者：
Star, WM
中科院分区：
文献类型：
--
作者：
Robinson, DJ;de Bruijn, HS;Star, WM
研究了5-氨基乙酰丙酸(ALA)诱导的原卟啉IX(PPIX)在SKH HR1无毛小鼠正常皮肤表面光动力疗法(PDT)过程中的光漂白，考察了光剂量和注量率对光漂白动力学和光漂白幅度的影响，以及对相应的光动力学损伤的影响。结果表明，光漂白不能用总光剂量来预测，光漂白是在较宽的初始PpIX荧光强度范围内监测的，PpIX光漂白速率不是光通量速率的简单函数，而是依赖于敏化剂的初始浓度。此外，在高注量率(50-150 mW/cm(2)，514 nm)下，氧耗尽显示出显著的影响。光漂白相对于光剂量的速率和相应的PDT损伤都随着注量率的降低而增加。因此，我们认为，将漂白剂量定义为导致荧光信号1/e减少的战斗剂量不足以描述光漂白和PDT诱导的损伤的动力学。我们检测到在照射初期形成PpIX光产物，这些光产物本身也被光漂白。在没有氧气的情况下，PPIX及其光产物不会被光漂白。我们提出了一种计算浅层光动力疗法治疗剂量的方法，该方法与光动力疗法的损伤有很强的相关性。
The photobleaching of 5-aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) was investigated during superficial photodynamic therapy (PDT) in normal skin of the SKH HR1 hairless mouse, The effects of light dose and fluence rate on the dynamics and magnitude of photobleaching and on the corresponding PDT-induced damage were examined. The results show that the PDT damage cannot be predicted by the total light dose, Photobleaching was monitored over a wide range of initial PpIX fluorescence intensities, The rate of PpIX photobleaching is not a simple function of fluence rate but is dependent on the initial concentration of sensitizer. Also, at high fluence rates (50-150 mW/cm(2), 514 nm) oxygen depletion is shown to have a significant effect. The rate of photobleaching with respect to light dose and the corresponding PDT damage both increase with decreasing fluence rate. We therefore suggest that the definition of a bleaching dose as the fight dose that causes a 1/e reduction in fluorescence signal is insufficient to describe the dynamics of photobleaching and PDT-induced damage, We have detected the formation of PpIX photoproducts during the initial period of irradiation that were themselves subsequently photobleached. In the absence of oxygen, PpIX and its photoproducts are not photobleached. We present a method of calculating a therapeutic dose delivered during superficial PDT that demonstrates a strong correlation with PDT damage.