Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar, Germany.
Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Sci Rep. 2017 Mar 15;7:44537. doi: 10.1038/srep44537.
Following corneal epithelium scratches, mouse corneas were infected with the multidrug resistant (MDR) P. aeruginosa strain PA54. 24 hours later, 0% (for control group), 0.01%, 0.05% or 0.1% Chlorin e6 (Ce6), a second generation photosensitizer derived from chlorophyll, was combined with red light, for photodynamic inactivation (PDI). 1 hour or 2 days later, entire mouse eyes were enucleated and homogenized for counting colony forming units (CFU) of P. aeruginosa. For comparison, 0.1% Ce6 mediated PDI was started at 12 hours post infection, and 0.005% methylene blue mediated PDI 24 hours post infection. Clinical scores of corneal manifestation were recorded daily. Compared to the control, CFU 1 hour after PDI started 24 hours post infection in the 0.01% Ce6 and 0.05% Ce6 groups were significantly lower (more than one log reduction), the CFU 2 days post PDI higher in the 0.1% Ce6 group, clinical score lower in the 0.1% Ce6 group at 1 day post PDI. These findings suggest that PDI with Ce6 and red light has a transient efficacy in killing MDR-PA in vivo, and repetitive PDI treatments are required to fully resolve the infection. Before its clinical application, the paradoxical bacterial regrowth post PDI has to be further studied.
在角膜上皮划痕后，用多药耐药（MDR）铜绿假单胞菌菌株 PA54 感染小鼠角膜。24 小时后，用 0%（对照组）、0.01%、0.05%或 0.1%氯代叶绿素 e6（Ce6）与红光联合进行光动力失活（PDI），后者是从叶绿素衍生而来的第二代光敏剂。1 小时或 2 天后，将整个小鼠眼球取出并匀浆，以计数铜绿假单胞菌的菌落形成单位（CFU）。为了进行比较，在感染后 12 小时开始 0.1%Ce6 介导的 PDI，在感染后 24 小时开始 0.005%亚甲蓝介导的 PDI。每天记录角膜表现的临床评分。与对照组相比，在感染后 24 小时开始 PDI 后 1 小时，0.01%Ce6 和 0.05%Ce6 组的 CFU 明显降低（减少一个对数级以上），0.1%Ce6 组的 PDI 后 2 天的 CFU 较高，PDI 后 1 天的 0.1%Ce6 组的临床评分较低。这些发现表明，Ce6 和红光的 PDI 对体内 MDR-PA 具有短暂的杀伤作用，需要重复进行 PDI 治疗才能完全解决感染。在其临床应用之前，还需要进一步研究 PDI 后细菌的反常再生长现象。
