Departamento de Clínica Infantil, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, Monte Alegre, 14040-904, Ribeirão Preto, São Paulo, Brazil.
Departamento de Biologia Celular, Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, Monte Alegre, 14049-900, Ribeirão Preto, São Paulo, Brazil.
Lasers Med Sci. 2021 Jun;36(4):913-926. doi: 10.1007/s10103-020-03180-2. Epub 2020 Nov 4.
Antimicrobial photodynamic therapy (aPDT) is a complementary therapeutic modality for periodontal and endodontic diseases, in which Gram-negative bacteria are directly involved. Currently, there are few evidences regarding the effects of aPDT on bacterial components such as lipopolysaccharide (LPS) and it would represent a major step forward in the clinical use of this therapy. In this context, this study aimed to evaluate the efficacy of different photosensitizers (PSs) used in aPDT in LPS inhibition. Four PSs were used in this study: methylene blue (MB), toluidine blue (TBO), new methylene blue (NMB), and curcumin (CUR). Different approaches to evaluate LPS interaction with PSs were used, such as spectrophotometry, Limulus amebocyte lysate (LAL) test, functional assays using mouse macrophages, and an in vivo model of LPS injection. Spectrophotometry showed that LPS decreased the absorbance of all PSs used, indicating interactions between the two species. LAL assay revealed significant differences in LPS concentrations upon pre-incubation with the different PSs. Interestingly, the inflammatory potential of LPS decreased after previous treatment with the four PSs, resulting in decreased secretion of inflammatory cytokines by macrophages. In vivo, pre-incubating curcumin with LPS prevented animals from undergoing septic shock within the established time. Using relevant models to study the inflammatory activity of LPS, we found that all PSs used in this work decreased LPS-induced inflammation, with a more striking effect observed for NMB and curcumin. These data advance the understanding of the mechanisms of LPS inhibition by PSs.
抗菌光动力疗法 (aPDT) 是一种牙周病和牙髓病的辅助治疗方法，其中革兰氏阴性菌直接参与其中。目前，关于 aPDT 对细菌成分（如脂多糖 (LPS)）的影响的证据很少，这将是该疗法临床应用的重要一步。在这种情况下，本研究旨在评估不同光敏剂 (PS) 在 LPS 抑制中的疗效。本研究使用了四种 PS：亚甲蓝 (MB)、甲苯胺蓝 (TBO)、新亚甲蓝 (NMB) 和姜黄素 (CUR)。使用了不同的方法来评估 LPS 与 PS 的相互作用，例如分光光度法、鲎试剂 (LAL) 试验、使用小鼠巨噬细胞的功能测定以及 LPS 注射的体内模型。分光光度法表明 LPS 降低了所有使用的 PS 的吸光度，表明两种物质之间存在相互作用。LAL 试验显示，LPS 与不同 PS 预孵育后 LPS 浓度存在显着差异。有趣的是，四种 PS 预处理后 LPS 的炎症潜力降低，导致巨噬细胞分泌的炎症细胞因子减少。在体内，在 LPS 中预先孵育姜黄素可防止动物在既定时间内发生感染性休克。使用相关模型研究 LPS 的炎症活性，我们发现本工作中使用的所有 PS 均降低了 LPS 诱导的炎症，其中 NMB 和姜黄素的作用更为明显。这些数据加深了对 PS 抑制 LPS 机制的理解。
