Injectable CNPs/DMP1-loaded self-assembly hydrogel regulating inflammation of dental pulp stem cells for dentin regeneration.

Vital pulp preservation, which is a clinical challenge of aseptic or iatrogenic accidental exposure of the pulp, in cases direct pulp capping is the main technology. Human dental pulp stem cells (hDPSCs) play a critical role in pulp tissue repair, but their differentiative ability could be inhibited by the potential infection and inflammatory response of the exposed pulp. Therefore, inflammatory regulation and differentiated promotion of hDPSCs are both essential for preserving living pulp teeth. In this study, we constructed a functional dental pulp-capping hydrogel by loading cerium oxide nanoparticles (CNPs) and dentin matrix protein-1 (DMP1) into an injectable Fmoc-triphenylalanine hydrogel (Fmoc-phe3 hydrogel) as CNPs/DMP1/Hydrogel for in situ drugs delivery. With a view to long-term storage and release of CNPs (anti-inflammatory and antioxidant) to regulate the local inflammatory environment and DMP1 to promote the regeneration of dentin. Results of CCK-8, LDH release, hemolysis, and Live/Dead assessment of cells demonstrated the good biocompatibility of CNPs/DMP1/Hydrogel. The levels of alkaline phosphatase activity, quantification of the mineralized nodules, expressions of osteogenic genes and proteins demonstrated CNPs/DMP1/Hydrogel could protect the activity of hDPSCs' osteogenic/dentinogenic differentiation by reducing the inflammation response via releasing CNPs. The therapy effects were further confirmed in rat models, CNPs/DMP1/Hydrogel reduced the necrosis rate of damaged pulp and promoted injured pulp repair and reparative dentin formation with preserved vital pulps. In summary, the CNPs/DMP1/Hydrogel composite is an up-and-coming pulp-capping material candidate to induce reparative dentin formation, as well as provide a theoretical and experimental basis for developing pulp-capping materials.

Effect and mechanism of reactive oxygen species-responsive nanoparticles on the regulation of human gingival fibroblast function and inflammation induced by lipopolysaccharide / 口腔疾病防治

Objective@#To investigate the effects of PssL-NAC reactive oxygen species (ROS)-responsive nanoparticles on intracellular ROS production, inflammatory factor levels, collagen production, cell function and Toll-like receptor 4 (TLR4), NF-κB nuclear factor-κB (p65) pathway protein expression in human gingival fibroblasts (HGFs) induced by Porphyromonas gingivalis-lipopolysaccharide (P.g-LPS).@*Methods@#This study was reviewed and approved by the ethics committee. PssL-NAC microspheres containing oil soluble antioxidant N-acetylcysteine (NAC) were obtained by connecting the hydrophobic end of polycaprolactone (PCL) and the hydrophilic end of polyethylene glycol (PEG) via thioketal (TK) bonds in response to ROS, and self loading in the aqueous and oil phases. After preparation of the PssL-NAC microspheres and aqueous NAC solution, successful synthesis of the nanoparticles was verified by transmission electron microscopy. Then, HGFs were exposed to P.g-LPS (0, 5, or 10 μg/mL), P.g-LPS (0, 5, or 10 μg/mL)+NAC, and P.g-LPS (0, 5, or 10 μg/mL)+PssL-NAC, and the ROS levels in the different groups were observed under confocal microscopy to determine the concentration of P.g-LPS for use in subsequent experiments. The groups were as follows: control group (no treatment), P.g-LPS group (HGFs treated with P.g-LPS), NAC group (HGFs treated with P.g-LPS and NAC), and PssL-NAC group (HGFs treated with P.g-LPS and PssL-NAC). Cell counting kit-8 (CCK-8) assays verified the biosafety of PssL-NAC. The ROS levels in the different groups were detected by DCFH-DA probes and observed via confocal microscopy. Real-time qPCR (RT-qPCR) was used to monitor the gene expression levels of the intracellular inflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), collagen 1 (COL1) and collagen 3 (COL3). The effect of PssL-NAC on the migration of HGFs was observed via the scratch test. The protein expression of TLR4-NF-κB, and phosphorylated p65 (p-p65) in the TLR4-NF-κB pathway was evaluated by Western blot.@*Results@#PssL-NAC had no significant effect on HGF proliferation (P>0.05). At elevated P.g-LPS concentrations, PssL-NAC maintained intracellular ROS levels approximately twice those in the control group (P<0.001). PssL-NAC significantly decreased P.g-LPS-induced IL-6 (P<0.001) and TNF-α (P<0.001) gene expression and increased COL1 gene expression (P<0.001). After P.g-LPS stimulation, PssL-NAC restored cell migration to the control level (P>0.05) and decreased the protein expression of TLR4 (P<0.001), p65 (P = 0.006), and p-p65 (P = 0.017) in the TLR4-NF-κB pathway.@*Conclusion@#PssL-NAC maintains the appropriate intracellular ROS concentration, alleviates P.g-LPS-induced inflammation in HGFs through the TLR4-NF-κB pathway, and restores the cell functions of collagen production and migration in an inflammatory environment.

Combined Black Phosphorus Nanosheets with ICG/aPDT is an Effective Anti-Inflammatory Treatment for Periodontal Disorders.

Introduction: Antibacterial photodynamic treatment (aPDT) has indispensable significance as a means of treating periodontal disorders because of its extraordinary potential for killing pathogenic bacteria by generating an overpowering amount of reactive oxygen species (ROS). The elevated ROS that may result from the antibacterial treatment procedure, however, could exert oxidative pressure inside periodontal pockets, causing irreparable damage to surrounding tissue, an issue that has severely restricted its medicinal applications. Accordingly, herein, we report the use of black phosphorus nanosheets (BPNSs) that can eliminate the side effects of ROS-based aPDT as well as scavenge ROS to produce an antibacterial effect. Methods: The antibacterial effect of ICG/aPDT was observed by direct microscopic colony counting. A microplate reader and confocal microscope enabled measurements of cell viability and the quantification of ROS fluorescence. BPNS administration regulated the oxidative environment. IL-1ß, IL-6, TNF-α, IL-10, TGF-ß, and Arg-1 mRNA expression levels were used to assess the inflammatory response after BPNS treatment. In vivo, the efficacy of the combination of BPNSs and ICG/aPDT was evaluated in rats with periodontal disease by histomorphometric and immunohistochemical analyses. Results: The CFU assay results verified the antibacterial effect of ICG/aPDT treatment, and ROS fluorescence quantification by CLSM indicated the antioxidative ability of the BPNSs. IL-1ß, IL-6, TNF-α, IL-10, TGF-ß, and Arg-1 mRNA expression levels were significantly decreased after BPNS treatment, confirming the in vitro anti-inflammatory effect of this nanomaterial. The histomorphometric and immunohistochemical analyses showed that the levels of proinflammatory factors decreased, suggesting that the BPNSs had anti-inflammatory effects in vivo. Conclusion: Treatment with antioxidative BPNSs gives new insights into future anti-inflammatory therapies for periodontal disease and other infection-related inflammatory illnesses and provides an approach to combat the flaws of aPDT.

High glucose levels contribute to vascular fibrosis via the activation of the endothelial-to-mesenchymal transition in periodontitis.

OBJECTIVE: To determine the changes of Porphyromonas gingivalis (P. gingivalis) growth and metabolism and identify whether the vascular epithelium change could be induced in diabetic periodontitis. BACKGROUND: Maintaining favourable vascular function is a precondition for periodontal regeneration. In diabetic periodontitis, high glucose levels could enhance the metabolism of pathogens, and a complex condition involving inflammation and high glucose levels would disrupt homeostasis of the epithelium and promote fibrosis by endothelial-to-mesenchymal transition (EndMT). METHODS: Porphyromonas gingivalis was cultured with glucose to judge its metabolic activity. Human umbilical vein endothelial cells (HUVECs) were treated with P. gingivalis-lipopolysaccharide (LPS) (10 µg/ml) and/or high glucose concentrations (25 mM), and transforming growth factor (TGF)-ß inhibitor was used to block EndMT. Inflammation level was assessed by flow cytometry. Multiple biological functions including EndMT, angiopoiesis, and cell migration were analysed. Additionally, gene expressions and protein levels were determined with qPCR and western blot, respectively. Finally, blood vessels were cultured ex vivo, and EndMT and fibrosis markers were detected by immunohistochemistry. RESULTS: Glucose could promote P. gingivalis growth and biofilm formation as well as the expression of virulence factor genes including FimA, RgpA, RgpB, and Kgp. P. gingivalis-LPS and glucose could increase intracellular reactive oxygen species (ROS) and promote fibrosis via EndMT in HUVECs, along with attenuating angiopoiesis and cell migration, which could be resumed by blocking EndMT with TGF-ß inhibitor. Vascular fibrosis was observed after the addition of glucose via EndMT regulation. CONCLUSION: Glucose augmented the growth and metabolism of P. gingivalis and promoted fibrosis by the activation of EndMT, as well as the inhibition of angiopoiesis and cell migration.