Faculty of Dentistry, Dental Research Institute, University of Toronto, Toronto, Ontario, Canada.
Ontario Centre for the Characterization of Advanced Materials (OCCAM), Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario, Canada.
Int Endod J. 2020 Jun;53(6):859-870. doi: 10.1111/iej.13283. Epub 2020 Mar 13.
To characterize a lipopolysaccharide (LPS)-treated dentine tissue model (LPS dentine) to analyse the efficacy of polycationic chitosan nanoparticles (CSnp) and/or dexamethasone conjugate chitosan nanoparticles (Dex-CSnp) on the viability/differentiation potential of stem cells from apical papilla (SCAP) when exposed to LPS dentine. A further aim was to understand the effect of macrophage-dependent inflammation on SCAP migration in the presence of LPS dentine.
A total of 88 dentine slabs were used. TOF-SIMS analysis was performed amongst the LPS-treated and untreated dentine groups (n = 2/group). The study was conducted using four dentine groups: no treatment (control); LPS treatment only; LPS treatment followed by CSnp conditioning; and LPS treatment followed by Dex-CSnp conditioning groups. SCAP adherence, viability, differentiation and biomineralization potential on dentine from different groups were studied using fluorescent and scanning electron microscopy. Inflammation by macrophages in response to LPS dentine was quantified, and effect on SCAP migration was analysed. Statistical analysis was performed using Student's t-test with a significance level of P < 0.05.
TOF-SIMS analysis confirmed LPS contamination. LPS dentine affected SCAP viability but not adherence to dentine (P < 0.001). Conditioning of LPS dentine with either nanoparticles improved SCAP viability (P < 0.01) and rescued other LPS related adverse effects on SCAPs, such as F-actin disruption, decrease in differentiation/biomineralization potential. IL-6 produced by macrophages in response to LPS-treated dentine impeded SCAP migration (P < 0.001), diminished on CSnp and Dex-CSnp conditioning groups (P < 0.01).
This study developed an LPS-dentine model and highlighted the ability of CSnp and Dex-CSnp to promote stem cell viability, migration, differentiation potential and reduce inflammation, providing an environment conducive for tissue regeneration/repair.
对脂多糖（LPS）处理牙本质组织模型（LPS 牙本质）进行特征分析，以研究聚阳离子壳聚糖纳米颗粒（CSnp）和/或地塞米松结合壳聚糖纳米颗粒（Dex-CSnp）在 LPS 牙本质存在的情况下对根尖乳头干细胞（SCAP）活力/分化潜能的作用。本研究的另一个目的是了解巨噬细胞依赖性炎症对 LPS 牙本质存在时 SCAP 迁移的影响。
本研究共使用了 88 个牙本质板。在 LPS 处理组和未处理组（每组 n=2）中进行了时飞行二次离子质谱（TOF-SIMS）分析。本研究共使用了 4 种牙本质组：无处理（对照）；仅 LPS 处理；LPS 处理后用 CSnp 调理；以及 LPS 处理后用 Dex-CSnp 调理组。通过荧光和扫描电子显微镜研究了来自不同组的牙本质上 SCAP 的黏附、活力、分化和生物矿化潜能。通过定量分析巨噬细胞对 LPS 牙本质的炎症反应，分析其对 SCAP 迁移的影响。采用 Student's t 检验进行统计学分析，显著性水平 P<0.05。
TOF-SIMS 分析证实了 LPS 的污染。LPS 牙本质影响 SCAP 的活力，但不影响其对牙本质的黏附（P<0.001）。用纳米颗粒对 LPS 牙本质进行调理可提高 SCAP 的活力（P<0.01），并挽救了 LPS 对 SCAP 的其他不利影响，如 F-肌动蛋白破坏、分化/生物矿化潜能降低。LPS 处理牙本质引发的巨噬细胞产生的白细胞介素 6（IL-6）阻碍了 SCAP 的迁移（P<0.001），但在 CSnp 和 Dex-CSnp 调理组中减弱（P<0.01）。
本研究建立了 LPS 牙本质模型，并强调了 CSnp 和 Dex-CSnp 促进干细胞活力、迁移、分化潜能和减少炎症的能力，为组织再生/修复提供了有利的环境。
