Biocompatibility and osteogenesis of the castor bean polymer doped with silica (SiO2) or barium titanate (BaTiO3) nanoparticles

PURPOSE: To evaluate the biocompatibility and osteogenesis of castor oil polymer doped with SiO2 or BaTiO3 nanoparticles.METHODS: Twenty four male rats Wistar were submitted to bone defect filled with castor oil polymer. The animals were distributed in two experimental groups had been formed with 12 animals each: Group 1 - Castor oil polymer doped with 0.30 grams of SiO2 replacing 0.30 grams of CaCO3. Group 2 - Castor oil polymer doped with 0.30 grams of BaTiO3 replacing 0.30 grams of CaCO3. Euthanasia occurred 30 and 60 days after surgery and the femurs were sent to histological analysis and MEV.RESULTS:The implants were biocompatible and allowed for progressive osteogenesis through osteoconduction in both observation periods. There was significant bone neoformation at 30 and 60 days in both groups within the histomorphometric evaluation, but group 1's osteogenesis was lesser in the 30 and 60-day periods observed when compared to the animals of group 2. The MEV morphometric evaluation evidenced a lesser percentage of osseous tissue filling within the BaTiO2-doped polymer.CONCLUSION:The castor oil polymer doped with SiO2 or BaTiO3 remained biocompatible and allowed for progressive osteogenesis in both observation periods.(AU)

Castor oil polyurethane containing silica nanoparticles as filling material of bone defect in rats / Poliuretana de mamona contendo nanopartículas de sílica como material de preenchimento de defeito ósseo em ratos

PURPOSE: To evaluate the biologic behavior of the castor polymer containing silica nanoparticles as a bone substitute in diafisary defect. METHODS: Twenty seven male rattus norvegicus albinus wistar lineage were submitted to bone defect filled with castor oil polymer. Three experimental groups had been formed with nine animals each: (1) castor oil polymer containing only calcium carbonate; (2) castor oil polymer with calcium carbonate and doped with 5 percent of silica nanoparticles; (3) castor polymer with calcium carbonate doped with 10 percent of silica nanoparticles; 3 animals of each group were submitted to euthanasia 15, 30 and 60 days after experimental procedure, and their femurs were removed to histological evaluation. RESULTS: there was bone growth in all the studied groups, with a greater tendency of growth in the group 1. After 30 days all the groups presented similar results. After 60 days a greater amount of fibroblasts, osteoblasts, osteocytes and osteoclasts in group 3 was observed, with integrated activity of 3 kinds of cells involved in the bone activation-reabsorption-formation. CONCLUSIONS: The castor polymer associated to the silica nanoparticles is biocompatible and allows osteoconduction. The presence of osteoprogenitors cells suggests silica osteoinduction capacity.(AU)

OBJETIVO: Avaliar o comportamento biológico do polímero de mamona contendo nanopartículas de sílica como substituto ósseo. MÉTODOS: Vinte e sete rattus norvergicus albinus, Wistar foram submetidos a defeito ósseo preenchido com polímero de mamona. Foram formados três grupos experimentais, com nove ratos cada: (1) Polímero com carbonato de cálcio; (2) Polímero com carbonato de cálcio dopado com 5 por cento de nanopartículas de sílica; (3) Polímero com carbonato de cálcio dopado com 10 por cento de nanopartículas de sílica; três animais de cada grupo foram submetidos à eutanásia 15, 30 e 60 dias após o procedimento experimental e os fêmures removidos e submetidos à avaliação histológica. RESULTADOS: Houve crescimento ósseo em todos os grupos estudados, com maior tendência de crescimento no grupo contendo polímero de mamona acrescido apenas por carbonato de cálcio. Aos 30 dias, todos os grupos apresentaram resultados semelhantes. Aos 60 dias, notou-se maior presença de fibroblastos, osteoblastos, osteócitos e osteoclastos no grupo 3, com persistência da atividade integrada dos três tipos de células envolvidas no processo de ativação-reabsorção-formação óssea. CONCLUSÕES: O polímero de mamona associado com nanopartículas de sílica é biocompatível e permite a osteocondução. A presença de células osteoprogenitoras nos implantes contendo 10 por cento de sílica indica sua capacidade osteoindutora.(AU)