Leite Ilaiáli S, Geralde Mariana C, Salina Ana C G, Medeiros Alexandra I, Dovigo Lívia N, Bagnato Vanderlei S, Inada Natalia M
University of São Paulo, São Carlos Institute of Physics, Group of Optics, Av. Trabalhador São-carlense, 400 São Carlos, SP, Brazil.
Federal University of São Carlos, PPGBiotec, São Carlos, SP, Brazil.
J Biophotonics. 2018 Jan;11(1). doi: 10.1002/jbio.201600283. Epub 2017 May 18.
Pneumonia is the main cause of children mortality worldwide, and its major treatment obstacle stems from the microorganisms increasing development of resistance to several antibiotics. Photodynamic therapy has been presenting, for the last decades, promising results for some subtypes of cancer and infections. In this work we aimed to develop a safe and efficient in vitro protocol for photodynamic inactivation of Streptococcus pneumoniae, one of the most commonly found bacteria in pneumonia cases, using two near-infrared light sources and indocyanine green, a FDA approved dye. Photodynamic inactivation experiments with bacteria alone allowed to determine the best parameters for microbial inactivation. Cytotoxicity assays with RAW 264.7 macrophages evaluated the safety of the PDI. To determine if the photodynamic inactivation had a positive or negative effect on the natural killing action of macrophages, we selected and tested fewer indocyanine green concentrations and 10 J/cm on macrophage-S. pneumoniae co-cultures. We concluded that ICG has potential as a photosensitizer for near-infrared photodynamic inactivation of S. pneumoniae, producing minimum negative impact on RAW 264.7 macrophages and having a positive interaction with the immune cell's microbicidal action.
肺炎是全球儿童死亡的主要原因，其主要治疗障碍源于微生物对多种抗生素的耐药性不断增强。在过去几十年中，光动力疗法在某些癌症和感染亚型的治疗中显示出了有前景的结果。在这项工作中，我们旨在开发一种安全有效的体外方案，使用两种近红外光源和FDA批准的染料吲哚菁绿，对肺炎链球菌（肺炎病例中最常见的细菌之一）进行光动力灭活。单独对细菌进行的光动力灭活实验有助于确定微生物灭活的最佳参数。用RAW 264.7巨噬细胞进行的细胞毒性试验评估了光动力灭活的安全性。为了确定光动力灭活对巨噬细胞的天然杀伤作用有正面还是负面影响，我们在巨噬细胞 - 肺炎链球菌共培养物中选择并测试了较低浓度的吲哚菁绿和10 J/cm²的剂量。我们得出结论，吲哚菁绿有潜力作为肺炎链球菌近红外光动力灭活的光敏剂，对RAW 264.7巨噬细胞产生最小的负面影响，并与免疫细胞的杀菌作用产生积极相互作用。
