The combined application of rat bone marrow mesenchymal stem cells and bioceramic materials in the regeneration of dental pulp-like tissues

Background: To observe the effects of combined application of rat bone marrow mesenchymal stem cells (rBMSCs) and a bioceramic material on pulp-like tissue formation. Methods: Rat incisor root fragments without pulp tissues were prepared and filled with a collagen scaffold seeded with rBMSCs, while one side of the root segment was covered by a bioceramic material (iRoot BP). After culture for 12 h, the root fragments were implanted subcutaneously for 3 months. Hematoxylin and eosin (HE) staining was applied to observe biocompatibility and the formation of pulp-like tissues. Incisor root fragments were divided into three parts (BP1/3 , M1/3, and D1/3) to analyze the area and number of new vessels. Immunohistochemical staining of neuroendocrine marker PGP9.5, dentin sialophosphoprotein ( DSPP ), and vascular endothelial growth factor (VEGF) was applied to observe the formation of pulp-like tissues. Root fragments filled with the collagen scaffold only were used as a control. Results: Three months after implantation, root fragments were collected, which were surrounded by a transparent tissue membrane with a good blood supply. The root fragment cavity was filled with pink vascularized pulp-like tissue. According to HE results, iRoot BP had good biocompatibility with new pulp-like tissues and few infiltrating inflammatory cells. Increases in the number and area of new blood vessels were observed in BP1/3 compared with the other two parts. Expression of PGP9.5 and DSPP showed that the newly formed tissues were similar to normal pulp tissues. Conclusion: iRoot BP has good biocompatibility and increases the number and area of new blood vessels. The combined application of stem cells and bioceramic materials may be a better method for pulp revascularization .