Abstract: Objective: To investigate the changes in the extracellular matrix (ECM) of dental pulp in a high glucose microenvironment and its effect on the migratory capacity of dental pulp stem cells (DPSCs) and repair of pulpal injuries. Methods: Eight-week-old male Wistar rats and GK rats were selected and stained with hematoxylin-eosin (HE) to observe the morphology of the dental pulp. Matson staining and immunohistochemical staining were used to detect the collagen fiber content and cross-linking in the pulpal ECM. Bio-type AFM was used to detect the stiffness of the pulpal ECM. A model of pulpal damage repair was established, and Micro-CT scanning reconstruction and HE staining were used to evaluate the repair of pulpal damage. CD146 and STRO-1 immunofluorescence co-staining was used to locate DPSCs. Immunofluorescence staining, scratch assay, and Transwell assay were used to detect the morphology, migration ability, and expression of mechanical signalling molecules of hDPSCs in glucose cross-linked ECM. An in vitro and in vivo model of ALT-711 inhibition of glucose cross-linking in ECM was constructed, and the morphology, migration capacity, and mechanosignalling molecules of hDPSCs were examined in relation to the repair of pulpal injury. Results: In the high glucose group, the pulp cross-sectional area was reduced, collagen fiber content was increased, the expression of collagen I (COL 1) and advanced glycation end-products (AGEs) was up-regulated, and the stiffness was increased. After pulpal injury, the high glucose group did not form restorative dentin bridges, pulpal ectopic calcification was significant, and CD146⁺ STRO-1⁺ DPSCs were distributed far from the injury site. In the glucose cross-linked ECM, hDPSCs had reduced area and shape factor, decreased migration ability, and increased expression of ITG-alpha 5 beta 1 and Yes-associated protein (YAP). hDPSCs in the high-glucose group formed restorative dentin bridges, ectopic calcification was reduced, and CD146⁺ STRO-1⁺ DPSCs were distributed far from the injury site after the ALT-711 intervention. After ALT-711 intervention, the formation of restorative dentin bridges and ectopic calcification were reduced in the high glucose group, CD146⁺ STRO-1⁺ DPSCs were distributed near the injury site, and the morphology and migration of hDPSCs were improved and the mechanical signals were weakened. Conclusion: The high glucose microenvironment induces abnormal deposition and excessive cross-linking of pulpal ECM collagen, which in turn leads to impaired migration of DPSCs and impaired pulpal damage repair through activation of the ITG-YAP mechanical signalling axis. Targeted inhibition of ECM glucose cross-linking can rescue the impaired migration ability and abnormal mechanical signals of DPSCs and promote pulpal injury repair.

Key words: high glucose microenvironment, extracellular matrix, pulp injury and repair, dental pulp stem cells, migration