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.