目的研究ALA-PpⅨ在皮肤癌细胞中的药代动力学规律,分析ALA-PDT对皮肤癌细胞的光动力作用机制。方法利用荧光光谱技术测量皮肤癌细胞A431和A375的ALA-PpⅨ的荧光强度。利用激光共聚焦显微技术研究ALA-PpⅨ在皮肤癌细胞中的分布。用倒置相差显微镜观察ALA-PDT作用后细胞的形态学变化。使用CCK-8(Cell Counting Kit-8)比色法测定ALA-PDT后细胞的存活率。结果两种皮肤癌细胞内ALA-PpⅨ的含量随着ALA浓度的增大而增加,当ALA浓度为0.6 mM时,ALA-PpⅨ的含量已基本达到饱和,0.6 mM为最佳的药物孵育浓度。给予细胞0.6 mM ALA孵育4 h后,检测到ALA-PpⅨ弥散分布于两种皮肤癌细胞的胞浆内和细胞膜上。两种细胞经ALA-PDT后的形态发生显著变化。在光剂量增加到1.74 J/cm2时,A431和A375细胞的存活率均下降到25%以下。结论两种皮肤癌细胞吸收ALA后合成PpⅨ的特性没有显著差异。在相同孵育时间条件下,A431合成PpⅨ的含量比A375高。A431和A375对ALA-PpⅨ的最佳药物孵育浓度为0.6 mM。ALA-PDT对两株皮肤癌细胞均有明显的抑制作用,A431对ALA-PDT更敏感。 Objective To study the pharmacokinetics of ALA-PpⅨ in skin cancer cells and analyze the mechanism of action of ALA-PDT on skin cancer cells. Methods The fluorescence intensity of ALA-PpⅨ in skin cancer cells A431 and A375 was measured by fluorescence spectroscopy. The distribution of ALA-PpⅨ in human skin cancer cells was studied by laser confocal microscopy. The morphological changes of cells after ALA-PDT treatment were observed by inverted phase contrast microscope. Cell viability was measured after ALA-PDT using the CCK-8 (Cell Counting Kit-8) colorimetric assay. Results The content of ALA-PpⅨ in both skin cancer cells increased with the increase of ALA concentration. When the ALA concentration was 0.6 mM, the content of ALA-PpⅨ was almost saturated, and 0.6 mM was the best concentration. ALA-PpIX was found diffusely distributed in the cytoplasm and the cell membrane of both skin cancer cells after incubation of cells with 0.6 mM ALA for 4 h. Both cells undergo significant morphological changes after ALA-PDT. At light doses up to 1.74 J / cm2, the viability of both A431 and A375 cells dropped below 25%. Conclusion There was no significant difference in the characteristics of PpⅨ after two kinds of skin cancer cells absorbed ALA. Under the same incubation time, A431 synthesized PpIX content higher than A375. The optimal drug incubation concentration for ALA-PpIX by A431 and A375 was 0.6 mM. ALA-PDT significantly inhibited both skin cancer cells and A431 was more sensitive to ALA-PDT.