Juzenas Petras, Sharfaei Soraya, Moan Johan, Bissonnette Robert
Division of Dermatology, Notre-Dame Hospital, Montreal University Hospital Center, 1560 Sherbrooke Street East, Rm. K-5201, Québec, H2L 4M1, Montreal, Canada.
J Photochem Photobiol B. 2002 May;67(1):11-7. doi: 10.1016/s1011-1344(02)00269-5.
Accumulation of protoporphyrin IX (PpIX) was investigated in normal skin and UV-induced tumours in hairless mice after topical application of a cream containing 2, 8 or 16% of 5-aminolevulinic acid methyl ester (ALA-Me). Higher levels of PpIX were measured in tumours compared to normal skin. The maximal amount of PpIX was reached at 1.5, 3 and 4 h after 2, 8 and 16% ALA-Me application, respectively. Higher tumour to normal skin PpIX fluorescence ratios were measured after application of 8 and 16% ALA-Me than after application of 2%. After irradiation with a broad spectrum of visible light from a slide projector, more than 90% of PpIX was bleached by fluences of 36 and 48 J/cm2, at fluence rates of 10 and 40 mW/cm2 respectively. At these fluences, the PpIX photobleaching rate was significantly higher (P<0.05) in normal mouse skin than in tumours. In addition, for a given fluence, more PpIX was photobleached at the lower fluence rate (10 mW/cm2) than at the higher fluence rate (40 mW/cm2) in normal skin (P<0.001) as well as in tumours (P<0.05) after exposure to 24 J/cm2 of light. In conclusion, the highest tumour to normal skin PpIX ratio was observed 3 h after application of 8% ALA-Me, suggesting that light exposure should be performed at this time in order to achieve an optimal PDT effect in this tumour model.
在无毛小鼠的正常皮肤和紫外线诱导的肿瘤中，研究了局部应用含2%、8%或16% 5-氨基乙酰丙酸甲酯（ALA-Me）的乳膏后原卟啉IX（PpIX）的蓄积情况。与正常皮肤相比，肿瘤中检测到的PpIX水平更高。分别在应用2%、8%和16% ALA-Me后1.5小时、3小时和4小时达到PpIX的最大量。应用8%和16% ALA-Me后测得的肿瘤与正常皮肤PpIX荧光比值高于应用2%后。在用幻灯机发出的广谱可见光照射后，分别以10和40 mW/cm²的光通量率，36和48 J/cm²的光通量可使90%以上的PpIX漂白。在这些光通量下，正常小鼠皮肤中PpIX的光漂白率显著高于肿瘤（P<0.05）。此外，对于给定的光通量，在正常皮肤（P<0.001）以及肿瘤（P<0.05）中，暴露于24 J/cm²光照后，较低光通量率（10 mW/cm²）下比高光通量率（40 mW/cm²）下有更多的PpIX被光漂白。总之，应用8% ALA-Me后3小时观察到肿瘤与正常皮肤的PpIX比值最高，这表明为了在该肿瘤模型中实现最佳的光动力治疗效果，应在此时间进行光照。
