Photodynamic effects using a diode laser with mono-L-aspartyl Chlorin e6 for implanted mice tumor

使用光敏剂药物Photofrin的光动力疗法（PDT）最近被日本卫生和福利部批准用于治疗早期肺癌、食管癌、胃癌、子宫癌和子宫发育不良。作者使用二极管激光和另一种光敏剂单l -天冬氨酸氯e6 （NPe6）对小鼠植入式纤维肉瘤进行了光动力治疗，避免了任何热效应，并取得了肿瘤治疗效果。在100mW/cm^2光照下，组织温升为3.8 C，低于热疗的温度范围。在本研究中，PDT在给药5.0 mg/kg NPe6 5小时后进行。分别为50,100,150和200 J/cm^2，肿瘤治愈率分别为20%，50%，70%和90%。此外，当激光照射量为1.25、2.5、5.0、7.5和10.0 mg/kg NPe6，照射量为100 J/cm^2时，肿瘤治愈率分别为0、20、50、70和90%。在一些动物中，肿瘤复发似乎发生在肿瘤的较深层。因此，我们研究了PDT的影响与PDT手术后肿瘤深部NPe6残留量之间的关系。我们使用CCD摄像系统测量荧光强度，以评估NPe6在距肿瘤表面3mm处的残留量。激光照射50j、100j、150 j和200J/cm^2后NPe6残留量与无激光照射的比值分别为73.4、36.0、22.0和15.9%。这些结果表明，肿瘤组织中NPe6水平的一定提高和到达肿瘤深层的激光照射剂量的一定增加导致治愈率的提高。此外，PDT的有效性以及PDT后的肿瘤复发率在一定程度上取决于到达肿瘤深层的总激光剂量。此外，PDT的效果往往与PDT的光漂白量有关。

Photodynamic therapy (PDT) using the photosensitizer drug Photofrin has recently been approved for the treatment of early stage lung cancer, esophageal cancer, gastric cancer, uterine cancer and uterine dysplasia by the Japanese Ministry of Health and Welfare. The authors performed photodynamic therapy, avording any hyperthermic effects, using a diode laser and another photosensitizer mono-L-aspartyl chlorin e6 (NPe6) in an implanted fibrosarcoma in mice and achieved tumor therapeutic effects. The tissue temperature rise was 3.8ﾟC when 100mW/cm^2 light was delivered, this temperature being below the temperature range of hyperthermia. In the present study, PDT was performed 5 hours following the administration of 5.0 mg/kg NPe6. With 50,100,150 and 200 J/cm^2, tumor cure rates were 20,50,70 and 90%, respectively. In addition, when PDT was performed with administration of 1.25,2.5,5.0,7.5 and 10.0 mg/kg NPe6 with 100 J/cm^2 laser exposure, tumor cure rates were 0,20,50,70 and 90%, respectively. In some arimals, tumor recurrence seemed to occur from deeper layr of tumors. Therefore, the relationship between the effects of PDT and residual amounts of NPe6 in the deeper level of tumors following the PDT procedure were examined. We used a CCD camera system to measure the fluorescence intensity to evaluate the residual amount of NPe6 at 3mm from the tumor surface. The ratio of the residual amount of NPe6 following 50,100,150 and 200J/cm^2 laser exposure to no laser exposure were 73.4,36.0,22.0 and 15.9% respectively. These results suggest that a certain increase in the tumor tissue level of NPe6 and a certain increase of laser light dose reaching deeper layr of tumor caused an increase in percent cure. In addition, the effectiveness of PDT and also tumor recurrence following PDT depend to some extent on the total laser laser dose reaching deeper layrs of tumors. Furthermore, the effectiveness of PDT tends to correlate with the amount of photobleaching by PDT.