Alkaline Treatment Enhances the Anti-Inflammatory and Reparative Potential of Dentin Matrix Proteins in Inflamed Pulp.

Introduction: To investigate the effects of dentin matrix-extracted complex proteins (DMEPs), especially basic-extracted DMEP (bDMEP), on the regulation of pulp inflammation and repair processes.

Methods: Protein components of neutral-extracted DMEP (nDMEP) and bDMEP were analyzed using a cytokine array and ELISA. Human dental pulp cells stimulated by lipopolysaccharide (LPS-hDPCs) were treated with nDMEP and bDMEP. CCK-8 and transwell experiments were employed to assess cell proliferation and migration. The expression levels of genes and proteins related to inflammation and odontogenic differentiation were analyzed through quantitative real-time polymerase chain reaction, ELISA, immunofluorescence staining, and western blot. In vivo, gelatin sponges containing nDMEP or bDMEP were employed as pulp-capping materials in a rat pulpitis model. Histological staining was performed to evaluate inflammation and tissue repair in inflamed pulp tissue.

Results: Compared with nDMEP, alkaline treatment significantly increased the content of multiple growth factors (C-X-C motif chemokine ligand 14, bone morphogenetic protein-2, transforming growth factor-beta1, transforming growth factor-beta2, osteopontin, insulin-like growth factor binding protein-2) and decreased some inflammatory mediators (macrophage inflammatory protein-1, interleukin (IL)-17, intercellular adhesion molecule-2, neural cell adhesion molecule-1) in DMEP. bDMEP enhanced the proliferation and chemotaxis of LPS-hDPCs. DMEP, especially bDMEP, inhibited the levels of proinflammatory cytokines (IL-1β, IL-6, tumor necrosis factor-α, CXCL10) while enhancing the expression of odontogenesis-related genes (dentin matrix protein 1, dentin sialophosphoprotein, collagen type I, alkaline phosphatase) in LPS-hDPCs. In vivo, bDMEP effectively reduced inflammatory infiltration and facilitated formation of dentin-like mineralization in a rat pulpitis model.

Conclusions: Alkaline treatment significantly improved the bioactivity of growth factors derived from the dentin matrix, alleviating the pulpal inflammatory response and facilitating biomimetic repair in inflamed pulp tissue.