Hussein Hebatullah, Kishen Anil
The Kishen Lab, Dental Research Institute, University of Toronto, Toronto, ON M5G 1G6, Canada.
Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada.
J Clin Med. 2020 Mar 9;9(3):730. doi: 10.3390/jcm9030730.
The biological aim of root canal treatment is to facilitate periapical tissue healing following endodontic therapy. This study aimed to develop an organotypic infected root canal model to understand the interaction of bacterial biofilm with macrophages and study the therapeutic effect of engineered bioactive chitosan nanoparticles (CSnp) on macrophages. Ex-vivo experiments were conducted in two phases; Phase-1: biofilms (two and six weeks old) developed in organotypic root canal model were used to characterize residual biofilm after conventional chemical treatment alone and combined with CSnp utilizing Confocal Laser Scanning Microscopy, Scanning Electron Microscopy and colony-forming units from pulverized dentin. Phase-2: The interaction of post-treatment biofilm and RAW macrophages was evaluated regarding pro/anti-inflammatory markers, cell viability and spreading at 24, 48 and 72 h. Compared to conventionally disinfected six-week-old biofilm, CSnp resulted in less viable bacteria ( < 0.01). Scanning electron micrographs demonstrated disruption of the biofilm. CSnp exhibited less residual bacterial load in pulverized dentin ( < 0.001). Macrophage interaction with CSnp-treated biofilm reduced proinflammatory markers (nitric oxide, TNF-α, IL-1β, and IL-6), increased anti-inflammatory marker (TGF-β1) and enhanced cell survival and spreading over time ( < 0.01 at 72 h). Engineered chitosan nanoparticles concurrently inactivated biofilm and altered the inflammatory response of macrophages that would promote healing.
根管治疗的生物学目的是促进牙髓治疗后根尖周组织的愈合。本研究旨在建立一种器官型感染根管模型，以了解细菌生物膜与巨噬细胞的相互作用，并研究工程化生物活性壳聚糖纳米颗粒（CSnp）对巨噬细胞的治疗效果。体外实验分两个阶段进行；第一阶段：利用共聚焦激光扫描显微镜、扫描电子显微镜和粉碎牙本质中的菌落形成单位，对在器官型根管模型中形成的生物膜（两周和六周龄）进行常规化学处理单独处理以及与CSnp联合处理后，表征残留生物膜。第二阶段：在24、48和72小时评估处理后生物膜与RAW巨噬细胞的相互作用，涉及促炎/抗炎标志物、细胞活力和细胞铺展情况。与传统消毒的六周龄生物膜相比，CSnp导致存活细菌减少（<0.01）。扫描电子显微镜照片显示生物膜受到破坏。CSnp在粉碎牙本质中的残留细菌载量较低（<0.001）。巨噬细胞与经CSnp处理的生物膜相互作用可降低促炎标志物（一氧化氮、TNF-α、IL-1β和IL-6），增加抗炎标志物（TGF-β1），并随着时间的推移提高细胞存活率和促进细胞铺展（72小时时<0.01）。工程化壳聚糖纳米颗粒同时使生物膜失活并改变巨噬细胞的炎症反应，从而促进愈合。
