Avaliação de matriz óssea humana mineralizada e desmineralizada como Scaffold para bioengenharia tecidual óssea

• Ano de defesa: 2017
• Autor(a) principal: Bruno Machado Bertassoli
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; Brasil; Programa de Pós-Graduação em Biologia Celular; UFMG
• Palavras-chave em Português: Banco de osso humano; Bioengenharia tecidual óssea; Células-tronco da polpa dentária; Scaffods; Matriz óssea desmineralizada; Matriz óssea mineralizada; Biologia Celular; Bioengenharia; Células-Tronco; Matriz Óssea
• Link de acesso: http://hdl.handle.net/1843/65660

The search for solutions for the bone loss or lesions has been stimulating researches to improve or develop new biomaterials to be used as bone grafts. Currently, allogeneic grafts represent an important alternative and have been widely used in orthopedic and odontologic clinics. Allogene bone has been utilized as biomaterial to fill the lesion site, promoting osteoconduction and osteoinduction. However, the potential of the use of the organic demineralized matrix has not been fully investigated thus far. Bone tissue bioengenering research has improved with the association of different cell types with modified 3D matrix. In this work, the potential of human bone matrix in mineralized (MHB) and demineralized (DHB) forms to induce dental pulp stem cell (DPSC) and osteogenic cell line (primary - PO; and immortalized - IO osteoblasts) proliferation and differentiation were evaluated in 3D culture. DPSC were isolated from Wistar rat incisive teeth; PO from 3 day-old rat calvariae; and the IO were commercialy obtained. Bone fragments were obtained from the Musculoskeletics Tissue Bank, at the University of Marília (SP, UNIOSS). The demineralized form of the bone graft was obtained in the lab using 10% EDTA as quelant solution. DPSC showed immunophenotipic and differentiation capacity characteristics similar to mesenchymal stem cells. PO and IO were confirmed by the expression of Osteopontin, BMP4, Type I Collagen and Runx2 and by their mineralization capacity after 21 days of culture in osteogenic media. In the characterization of the bone grafts, the MHB showed an opaque structure, with 55% of their pores > 500 μm while the DHB was found to be translucid, showing 76% of their pores > 500 μm. The demineralization process preserved the components of the organic matrix, as revealed by positive immunofluorescence for bone markers. PO and IO showed higher viability indexes when cultivated onto scaffolds of DHB compared to the data obtained with MHB. DPSC, however, showed the opposite result: viabilty indexes of these cells were higher when they were cultivated onto MHB as scaffolds. Scanning eletronic microscopy (SEM) revealed that all cell types could adhere and form a continuous layer on both scaffolds. The DHB was also able to induce higher alkaline fosfatase activity and larger mineralization nodules in all cell types (DPSC, PO and IO), compared to the data obtained with MHB. Therefore, these results showed an important potential of demineralized human bone matrix as a scaffold in bone tissue bioengenering.