RESUMO
Autologous bone is the most successful bone-grafting material; however, limited supply and donor site morbidity are problematic. Synthetic bone substitutes are effective, but healing is slow and unpredictable. Osseous wound healing may be enhanced if bone substitutes are combined with autologous bone marrow cells. To test this hypothesis, we created 40 calvarial defects in 20 12-week-old New Zealand White rabbits, divided into four groups: (1) unrepaired controls, (2) autologous bone grafts, (3) unseeded Caprotite (a polymer-ceramic composite) grafts, and (4) Caprotite grafts seeded with autologous bone marrow stromal cells. CT scans were obtained at 0, 6, and 12 weeks post-operatively, and defects were harvested for histology. Defects repaired with autologous bone had significantly (p < 0.05) more bone than the other three groups, although seeded Caprotite defects showed different wound-healing sequelae. Results suggest that seeded Caprotite scaffolds did not significantly enhance osseous defect healing compared with controls.
Assuntos
Transplante de Medula Óssea , Regeneração Óssea , Cicatrização , Implantes Absorvíveis , Análise de Variância , Animais , Substitutos Ósseos , Transplante Ósseo , Implantes Experimentais , Masculino , Modelos Animais , Osso Parietal/cirurgia , Coelhos , Estatísticas não Paramétricas , Engenharia TecidualRESUMO
A major cause of apical periodontitis after endodontic treatment is the bacterial infiltration which could have been challenged by the presence of a vital pulp. In this study, self-assembled, scaffoldless, three-dimensional (3D) tissues were engineered from dental pulp cells (DPCs) and assessed as a device for pulp regeneration. These engineered tissues were placed into the canal space of human tooth root segments that were capped on one end with calcium phosphate cement, and the entire system was implanted subcutaneously into mice. Histological staining indicated that after three- and five-month implantations, tooth roots containing 3D scaffoldless engineered tissues maintained a cellular, fibrous tissue throughout, whereas empty tooth roots remained predominantly empty. Immunostaining indicated that the tissue found in the root canals containing scaffoldless DPC engineered tissues was vascular, as characterized by the expression of CD31, and contained odontoblast-like cells organized along the length of the root wall as assessed by immunostaining for dentin sialoprotein. This study shows that 3D self-assembled scaffoldless DPC engineered tissues can regenerate a vital dental pulp-like tissue in a tooth root canal system and are therefore promising for endodontic therapy.
Assuntos
Polpa Dentária/citologia , Regeneração Tecidual Guiada/métodos , Tratamento do Canal Radicular/métodos , Engenharia Tecidual/métodos , Animais , Fosfatos de Cálcio/química , Técnicas de Cultura de Células , Microambiente Celular/fisiologia , Tecido Conjuntivo/irrigação sanguínea , Polpa Dentária/fisiologia , Cavidade Pulpar/citologia , Dentina/citologia , Proteínas da Matriz Extracelular/análise , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Odontoblastos/citologia , Fosfoproteínas/análise , Molécula-1 de Adesão Celular Endotelial a Plaquetas/análise , Agentes de Capeamento da Polpa Dentária e Pulpectomia/química , Preparo de Canal Radicular/métodos , Sialoglicoproteínas/análise , Tela Subcutânea/cirurgia , Fatores de Tempo , Alicerces Teciduais , Dente não Vital/patologiaRESUMO
The creation of novel bone substitutes requires a detailed understanding of the interaction between cells and materials. This study was designed to test certain polymers, specifically poly(caprolactone) (PCL), poly(D,L-lactic-CO-glycolic acid) (PLGA), and combinations of these polymers for their ability to support bone marrow stromal cell proliferation and differentiation. Bone marrow stromal cells were cultured from New Zealand White rabbits and were seeded onto glass slides coated with a thin layer of PCL, PLGA, and combinations of these two polymers in both a 40:60 and a 10:90 ratio. Growth curves were compared. At the end of 2 weeks, the cells were stained for both matrix mineralization and alkaline phosphatase activity. There was no statistically significant difference in growth rate of the cells on any polymer or polymer combination. However, there was a striking difference in Von Kossa staining and alkaline phosphatase staining. Cells on PCL did not show Von Kossa staining or alkaline phosphatase staining. However, in the 40:60 and 10:90 blends, there was both positive Von Kossa and alkaline phosphatase staining. These data indicate that PCL alone may not be a satisfactory material for the creation of a bone substitute. However, it may be used in combination with PLGA for the creation of a bone substitute material.
Assuntos
Materiais Biocompatíveis , Osteoblastos/citologia , Polímeros , Células Estromais/citologia , Animais , Diferenciação Celular , Células Cultivadas , CoelhosRESUMO
Blends of biodegradable polymers, poly(caprolactone) and poly(D, L-lactic-co-glycolic acid), have been examined as scaffolds for applications in bone tissue engineering. Hydroxyapatite granules have been incorporated into the blends and porous discs were prepared. Mechanical properties and degradation rates in vitro of the composites were determined. The discs were seeded with rabbit bone marrow or cultured bone marrow stromal cells and incubated under physiological conditions. Polymer/ceramic scaffolds supported cell growth throughout the scaffold for 8 weeks. Scanning and transmission electron microscopy, and histological analyses were used to characterize the seeded composites. This study suggests the feasibility of using novel polymer/ceramic composites as scaffold in bone tissue engineering applications.