Department of Laser Medicine, Chinese PLA General Hospital, Beijing 100853, China.
Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
Photodiagnosis Photodyn Ther. 2018 Jun;22:178-186. doi: 10.1016/j.pdpdt.2018.04.001. Epub 2018 Apr 4.
The incidence of Candida infections has increased for various reasons, including, the more frequent use of immunosuppresants or broad-spectrum antibiotics. Photodynamic inactivation (PDI) is a promising approach for treating localized Candida infections.
The PDI efficacies of three benzylidene cyclopentanone-based (BCB) photosensitizers (PSs: P1, P2 and Y1) against three fluconazole-resistant C. albicans (cal-1, cal-2, and cal-3) and one control C. albicans (ATCC 90028), respectively, were evaluated using an established plate dilution method. The binding of PSs to C. albicans was determined by fluorescence spectroscopy. The mechanism of antifungal PDI was investigated using confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM).
Three BCB PSs all bound rapidly to C. albicans. After incubation with PSs for 30 min and irradiation with a 532 nm laser for 10 min (40 mW cm, 24 J cm), the fungicidal activity was achieved as 7.5 μM for P1 and P2, and 25 μM for Y1. CLSM confirmed that P1 and Y1 were located in intracellular components, including mitochondria, while P2 bound to the protoplast exterior and failed to enter the cells. TEM revealed the damage of mitochondria ultrastructures after P1- or Y1-mediated PDI, consistenting with the CLSM results. However, most cells became edematous, enlarged or deformation after P2-mediated PDI.
The three BCB PSs all have remarkable PDI effects on C. albicans. The best effect is obtained by P1, which has one cationic charge with a proper lipophilicity. The respective subcellular localization of the three PSs led to different PDI mechanisms.
由于免疫抑制剂或广谱抗生素的使用频率增加等多种原因，念珠菌感染的发病率有所上升。光动力灭活（PDI）是治疗局部念珠菌感染的一种很有前途的方法。
采用已建立的平板稀释法，评价三种苯并环戊酮基（BCB）光敏剂（PS：P1、P2 和 Y1）对三种氟康唑耐药白色念珠菌（cal-1、cal-2 和 cal-3）和一株对照白色念珠菌（ATCC 90028）的 PDI 疗效。通过荧光光谱法测定 PS 与白色念珠菌的结合。通过共聚焦激光扫描显微镜（CLSM）和透射电子显微镜（TEM）研究抗真菌 PDI 的机制。
三种 BCB PS 均迅速与白色念珠菌结合。用 PS 孵育 30 分钟，然后用 532nm 激光照射 10 分钟（40mW/cm，24J/cm）后，P1 和 P2 的杀菌活性达到 7.5μM，Y1 达到 25μM。CLSM 证实 P1 和 Y1 位于细胞内成分（包括线粒体）中，而 P2 结合于原生质体外，无法进入细胞。TEM 显示 P1 或 Y1 介导的 PDI 后线粒体超微结构受损，与 CLSM 结果一致。然而，用 P2 介导 PDI 后，大多数细胞变得水肿、增大或变形。
三种 BCB PS 对白色念珠菌均具有显著的 PDI 作用。效果最好的是 P1，它带有一个正电荷和适当的亲脂性。三种 PS 的亚细胞定位导致了不同的 PDI 机制。
