5-ALA光动力疗法治疗裸鼠鼻咽癌移植瘤的疗效观察

5-Aminolevulinic Acid Mediated Photodynamic Therapy of Human Nasopharyngeal Carcinoma-bearing Nude Mice

目的观察5-ALA在体内合成PpⅨ及其分布情况,及局部和腹腔给药方式下,5-ALA-PDT对肿瘤生长的抑制作用。方法建立鼻咽癌移植瘤模型,利用荧光分光光度计检测5-ALA在荷瘤小鼠各脏器和组织中合成PpⅨ的情况,确定最适给药后最佳辐照时间;观察局部给药及腹腔给药(100mg/kg),两种方式下5-ALA-PDT3.0～3.5h后波长630nm功率密度100mW/cm2,能量密度100J/cm2辐照对裸鼠移植瘤生长的抑制作用;观察PDT后肿瘤细胞的组织病理学及超微结构的变化。结果5-ALA摄入后主要在肝脏和肿瘤组织中合成PpⅨ,3h左右PpⅨ在肿瘤组织中达峰值,是最适给药辐照时间;局部给药5-ALA-PDT抑制肿瘤生长的效果较好;5-ALA-PDT以诱导细胞凋亡及坏死为主要作用方式。结论3h左右是最适5-ALA给药辐照间隔时间;5-ALA-PDT是可行的鼻咽癌辅助治疗手段,且局部给药效果较好。

Objective To investigate the effect of photodynamic therapy （PDT） with 5-aminolevulinc acid （5-ALA） as a photosensitizer on naso-pharyngeal carcinoma. Methods The effect of 5-ALA-PDT on subcutaneously implanted CNE2 nasopharyngeal carcinoma cells in BALB/c nude mice was studied. Fluorescence spectrophotometer was applied to detect metabolic process of 5-ALA in nude mice bearing tumor. ALA at a dose of 100mg/kg was given intratumorally or intraperitoneally, and 3.0-3.5 h later tumors were subjected to laser irradiation （630 nm, 100 mW/cm62, 100 J/cm^2 ）. Tumor volume was calculated by the formula length × width × depth ×π/6 in the 1,3,7,10 and 14th days after irradiation. Two weeks after irradiation, the mice were sacrificed, tumor tissues were removed and detected under transmission electro- scope, and embedded in paraffin, slices were prepared and studied pathologically. Results 5-ALA mainly accumulated in tumor tissue and liver of nude mice after administration, and then turned into PplX. In tumor tissue, PpIX was detected 1 hour after 5-ALA administration, and gradually increased to summit at the time point of 3 hours, dropping thereafter. Tumor volume of ALA-PDT treated group was markedly smaller than the control groups, on the 14th day after PDT, tumor weight（gram） was 1. 353 ±0. 204, 2. 105 ±0. 255 and 3. 124 ±0. 380,with significant difference（P =0. 000）. The results of trans- mission electroscope confirmed that 5-ALA PDT induced apoptosis and necrosis of CNE2 cells. Conclusions Our results support the hypothesis that 5-ALA-PDT has potential for arresting the growth of human nasopharyngeal carcinoma.