| Background and Objectives:The ultimate goal of periodontal treatment is to regenerate the destructed tooth-supporting tissues.Periodontal ligament stem cells(PDLSCs),the adult stem cell population in tooth-supporting tissues has widely been studied and used for periodontal tissue regeneration.However,because of the lower rate of cell survival after MSC transplantation in various disease models,paracrine factions of MSCs have been receiving increased attentions as a regenerative mechanism.It has been documented that transplantation of conditoned medium,which inclued paracrine factions from periodontal ligament stem cells(PDLSCs-CM)acquired better periodontal tissue regeneration.Gingiva-derived mesenchymal stromal cells(GMSCs)have been considered as a promising alternative strategy for periodontal regeneration due to their potential for multilineage differentiation in vitro and the ability to form new bone in vivo.Moreover,gingiva-derived mesenchymal stem cells(GMSCs)are more readily available than PDLSCs.In this study,the effect and mechanism of GMSCs-CM on periodontal defect regeneration were studied by using periodontal tissue defect in rats,and compared with that of PDLSCs-CM.We aim to provide theoretical basis for the application of GMSCs-CM in the future.Methods:Human GMSCs were isolated from healthy gingival tissues by the finite dilution method and then cloned and cultured.Human gingival fibroblasts(GFs)were isolated from healthy gingival tissues with just passaging to P7.PDLSCs were a gift from Zhang Chunshu.When the cells cultured in a-MEM containing fetal serum grew to 70-80%fusion,the medium were replaced by serum-free a-MEM and cells were continued to culture for another 48 hours.Cell-free CM was collected from PDLSCs,GMSCs and GFs using ultracentrifugation.The conditoned medium was condensed 100 times.Periodontal tissue defect were created on the buccal side of the first molar in the left mandible of rats by surgical method.Bio-gide membrane loaded with concentrated CMs(a-MEM,GFs-CM,GMSCs-CM,PDLSCs-CM)were respectively transplanted into periodontal defects.1,2,4 weeks after the transplantation,animals were executed and the specimen including the left mandibular first molar and its around periodontal tissue were seperated and then decalcified.HE and Masson staining were processed to evaluating periodontal regeneration.TNF-?,IL-1? and IL-10 were immunohistochemically stained to analyze the expression of inflammatory factors in each group.Immunohistochemistry of BSP-II and Runx2 were processed to analyze osteoblast differentiation.Results:Histological observations showed that defects of each group was mainly occupied by inflammatory cells at 1 week.At 2 weeks,the newly formed bone trabeculae was obvious.Periodontal connective tissue was along the root surface and seemed loosely.At 4 weeks,the bone trabecular became more dense,the height of the new alveolar bone increased significantly,and the connective tissue was arranged in an orderly manner.At 4 weeks,as the area and height of neonatal alveolar bone were concerned,there were no significant difference between the GMSCs-CM group and the PDLSCs-CM group.But the area and height of neonatal alveolar bone in GMSCs-CM group and the PDLSCs-CM group were significantly higher than those of the other three groups.At 1 and 2 weeks,the expression of TNF-a and IL-1? in GMSCs-CM Group and PDLSC-CM group was significantly lower than those of other three groups,and there was no significant difference between these two groups.IL-10 expression was significantly higher in GMSCs-CM group than in PDLSCS-CM Group and other three groups.At 1,2 and 4 weeks,BSP-? and Runx2 expression in GMSCs-CM Group and PDLSCs-CM group were significantly higher than those of other three groups,with no significant difference between the two groups.Conclusions:Our results show GMSCs-CM transplantation can significantly promote periodontal defect regeneration in rats and achieve the same effect as PDLSCs-CM.The promotion mechanism of periodontal regeneration may be related to the regulation of inflammatory factors by conditoned medium derived from mesenchymal stem cells and its promotion of osteogenesis differentiation of bone progenitor cells in the wound region. |
PDF Full Text Request