This study aimed to examine whether the implantation of mesenchymal stem cells (MSCs) with endothelial cells (ECs) accelerates pulp tissue regeneration/healing and induces dentin bridge formation in a rat model of molar coronal pulp regeneration.Methods
The maxillary first molars of Wistar rats were subjected to pulpotomy. Then, pulp chambers were implanted with biodegradable hydrogel-made scaffolds carrying MSCs together or without dermal microvascular ECs, and the cavities were sealed with mineral trioxide aggregate. After 14 days, pulp samples were analyzed by immunohistochemistry; messenger RNA expression of B-cell lymphoma 2 (Bcl-2), chemokine (C-X-C motif) ligand 1 (Cxcl1), CXC receptor 2 (Cxcr2), and dentin sialophosphoprotein (Dspp) by quantitative polymerase chain reaction, and protein expression of nestin and vascular endothelial growth factor by Western blotting.Results
Teeth coimplanted with MSCs and ECs showed pulp healing with complete dentin bridge formation, whereas those implanted with MSCs alone had incomplete dentin bridges. Bcl-2, Cxcl1, Cxcr2, and Dspp messenger RNA levels were significantly up-regulated in the pulp of MSC/EC-implanted teeth compared with those in MSC-implanted teeth. Immunohistochemical analysis revealed the expression of nestin in odontoblastlike cells under dentin bridges in the MSC/EC coimplanted group. The density of CD31-expressing ECs and the expression of nestin and vascular endothelial growth factor proteins were significantly up-regulated in the MSC/EC-implanted pulp compared with the MSC-implanted pulp.Conclusions
The implantation of ECs with MSCs accelerated pulp tissue regeneration/healing and dentin bridge formation, up-regulated the expression of proangiogenic factors, and increased the density of ECs in pulpotomized rat molars.