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Propolis has a long ethnopharmacological history for oral periodontal diseases treatment. Propolis flavonoids are main active components for anti-inflammation and tissue protection. However, the intractable dissolution properties of propolis flavonoids and complex oral environment pose great challenges for periodontal delivery. In addition, the therapeutic mechanism as well as the therapeutic correlation of inflammation resolution and tissue regeneration remain unclear for propolis flavonoids. In this study, we constructed an in situ thermosensitive depot systems using total flavonoids from propolis-loaded cubic liquid crystals (TFP-CLC) hydrogel for periodontal delivery. TFP-CLC inhibited inflammatory cell infiltration, reactive oxygen species and the expression of inflammatory cytokines of NF-κB and IL-1β. In addition, alveolar bone and collagen were significantly regenerated after TFP-CLC administration according to micro-CT and immunohistochemistry. Mechanism studies suggested that TFP-CLC alleviated inflammation and promoted alveolar bone repair via regulating TLR4/MyD88/NF-κB p65 and RANK/NF-κB signaling pathways, respectively. Correlation analysis further confirmed that the inflammatory resolution produced by TFP-CLC could accelerate periodontal tissue regeneration. In summary, TFP-CLC is a promising multifunctional in situ thermo-sensitive hydrogel depots for periodontitis treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • We developed an ROS-responsive and scavenging bifunctional injectable CC-B-CAPE@CY-NPs hydrogel for periodontitis treatment. • The CC-B-CAPE@CY-NPs hydrogel was capable of scavenging excessive ROS and modulating polarization of M1 macrophages via regulating NF-κB signaling. • The CC-B-CAPE@CY-NPs hydrogel promotes the repair of alveolar bone by accelerating osteogenic transformation. Periodontitis is characterized by local inflammatory response and the resultant alveolar bone resorption. The elevated reactive oxygen species (ROS) level not only aggravates local inflammation but also prohibits osteogenesis. Hence, simultaneously scavenging ROS and triggering the activity of osteoblasts may produce synergism in periodontium regeneration. Herein, we developed an injectable hydrogel system, CC-B-CAPE@CY-NPs, for periodontitis treatment, in which caffeic acid phenethyl ester (CAPE), a naturally-occurring anti-inflammatory ingredient, was caged by aryl borate for ROS-responsive release. Meanwhile, the nanoparticles incorporating Chrysin (CY), another natural product with osteogenetic property, were also coated in the hydrogel. In vitro, the hydrogel was capable of scavenging the excessive ROS and modulating the polarization of M1 macrophages, highlighting its anti-inflammatory potency. In addition, its osteogenetic effect was verified by the increased ALP activity in the hydrogel-treated periodontal ligament stem cells (PDLSCs). Our studies revealed the anti-inflammatory stemmed from its ablation of NF-κB signaling, while the activation of Wnt/β-catenin cascade accounted for its osteogenetic potency. In a rat periodontitis model, the capability of reducing ROS levels, modulating macrophage polarization, and promoting osteogenesis was transformed into the recovery of destructed alveolar bone. All above, the hydrogel possesses great potential as a promising remedy for periodontitis. [ABSTRACT FROM AUTHOR]