Injectable Immunomodulatory Hydrogel Combined With Dental Pulp Stem Cell Secretome for Regenerative Endodontic Therapy: A Preclinical Translational Study

Abstract

Regenerative endodontic procedures have demonstrated potential for continued root development and tissue repair, but predictable restoration of functional pulp–dentin architecture remains limited by persistent inflammation, inadequate vascularization, and insufficient control of bacterial contamination. This translational study proposes to evaluate an injectable immunomodulatory hydrogel containing dental pulp stem cell-derived secretome as a cell-free strategy for enhancing pulp–dentin regeneration. A biodegradable hydrogel will be engineered to provide sustained release of angiogenic, immunoregulatory, and odontogenic bioactive factors while maintaining clinically appropriate injectability and degradation characteristics. Material properties will initially be characterized through rheological testing, degradation kinetics, swelling behavior, cytocompatibility, antibacterial assays, and controlled-release analysis. Human dental pulp stem cells and endothelial cells will subsequently be used to investigate cell migration, viability, odontogenic differentiation, tube formation, and inflammatory responses under simulated infected and hypoxic conditions. Expression of dentinogenic and angiogenic markers will be quantified using real-time polymerase chain reaction, immunofluorescence, and protein assays. The regenerative capacity of the optimized formulation will then be evaluated in an established immature-tooth animal model following canal disinfection. Experimental groups will compare hydrogel-secretome therapy with hydrogel alone, conventional blood-clot-based regenerative treatment, and untreated controls. Histomorphometric and micro-computed tomography analyses will assess intracanal tissue formation, root-wall thickening, apical closure, mineralized tissue deposition, vascularization, and inflammatory cell infiltration. Spatial immunohistochemistry will characterize macrophage polarization and the distribution of neural, vascular, and odontogenic markers within newly generated tissues. The proposed study addresses a major limitation of current regenerative endodontics by simultaneously targeting inflammation resolution, angiogenesis, antimicrobial protection, and tissue differentiation. A successful cell-free regenerative platform could simplify clinical translation compared with direct stem-cell transplantation while retaining important paracrine regenerative effects. The findings may establish a mechanistically informed biomaterial strategy for biologically based endodontic treatment of immature permanent teeth with pulp necrosis.