Shi Hang, Li Jiyang, Zhang Hui, Zhang Jie, Sun Hongying
Department of Stomatology, Huashan Hospital, Fudan University, No. 12, Rd Wulumuqi, Huahan Hospital, Shanghai, China.
School of Pharmacy, Fudan University, No. 826, Rd Zhangheng Shanghai, China.
Photodiagnosis Photodyn Ther. 2016 Sep;15:40-5. doi: 10.1016/j.pdpdt.2016.04.011. Epub 2016 Apr 30.
In this study, the photoinactivation of 5-aminolevulinic acid (ALA) has been investigated on Candida albicans biofilms in vitro.
After culture and proliferation of Candida albicans biofilms in vitro, the metabolic activity was confirmed using XTT reduction assay. Then, the suitable incubation time and concentration of ALA were determined by measuring PpIX accumulation quantities. Photosensitivity of the biofilms treated with ALA solution was studied in optical doses of 50, 100, 200 and 300J/cm(2) while light irradiation was applied by a red light semiconductor. Finally, rapid immunofluorescence staining method using the LIVE/DEAD FungaLight Yeast Viability Kit and XTT assay were conducted to visualize and quantify the antifungal effect of ALA-PDT on Candida albicans biofilms.
A 5h incubation time and 15mM ALA concentration were determined for this study. Photoinactivation of ALA-PDT on Candida albicans biofilms showed a significant increase of protoporphyrin IX (PpIX) in the biofilms. The metabolic activity of Candida albicans biofilms tread with ALA-PDT confirmed the inhibition efficacy compared with control groups. Upon radiation at 300J/cm(2), cells in Candida albicans biofilms were 74.45% inhibited.
PpIX can be absorbed in biofilm-grown Candida albicans in vitro and under appropriate parameters, photochemistry can be triggered by light in combination with ALA and inhibits Candida albicans biofilms effectively.
本研究对5-氨基酮戊酸（ALA）在体外对白色念珠菌生物膜的光灭活作用进行了研究。
体外培养并增殖白色念珠菌生物膜后，采用XTT还原试验确认其代谢活性。然后，通过测量原卟啉IX（PpIX）积累量来确定ALA的合适孵育时间和浓度。在用半导体红光照射时，研究了用ALA溶液处理的生物膜在50、100、200和300J/cm²光剂量下的光敏性。最后，使用LIVE/DEAD FungaLight酵母活力试剂盒和XTT试验的快速免疫荧光染色方法来可视化和量化ALA光动力疗法（ALA-PDT）对白色念珠菌生物膜的抗真菌作用。
本研究确定孵育时间为5小时，ALA浓度为15mM。ALA-PDT对白色念珠菌生物膜的光灭活显示生物膜中原卟啉IX（PpIX）显著增加。与对照组相比，用ALA-PDT处理的白色念珠菌生物膜的代谢活性证实了其抑制效果。在300J/cm²辐射下，白色念珠菌生物膜中的细胞受到74.45%的抑制。
PpIX可在体外被生物膜生长的白色念珠菌吸收，在适当参数下，光可与ALA结合引发光化学反应并有效抑制白色念珠菌生物膜。
