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Previous issue date: 2016-03-23 / Biomaterials, as an alternative to autogenous bone and other biological tissues, have been
widely used in oral and maxillofacial surgery. In this context, a biomaterial that functions as
a scaffold (osteoconductor), combined with a growth factor (osteoinductor), would be of
great interest for clinical application. Biodegradable polymers used for slow drug release
have been investigated, demonstrating good results and interesting potential. Growth
hormone (rhGH) may be released by incorporating it into these polymers. This study
aimed to evaluate cell adhesion and proliferation of a polymeric biomaterial for slow
release of rhGH. PLGA and PLGA/PCL (at a 70/30 ratio of PLGA to PCL) matrices were prepared by the
solvent evaporation method, combined or not with GH. The biomaterials were tested for
toxicity and cell viability using an MTT assay with NIH3T3 mouse cells (ATCC). Cell toxicity
was assessed at 24, 48, 72 hours, and 7 days of biomaterial exposure to culture medium.
After were tested?for cell adhesion and proliferation by culture in mesenchymal stem cells
derived from Wistar rat bone marrow, DAPI staining, and subsequent cell counting, in
addition to scanning electron microscopy. Cell adhesion and proliferation was assessed at
24 and 72 hours of biomaterial exposure to culture medium. All polymers had high cell viability rates. However, from 48 hours onwards, the groups with
rhGH-polymer combinations had better results than the polymer groups without
association with GH when compared to the control group. At 7 days of culture, only the
pure PLGA matrix showed a significant difference from the control group. These results
may suggest a preference of cells for the presence of rhGH in the biomaterial in culture
medium? especially in the PLGA matrix. GH appeared to contribute to the increase in cell
viability observed at some assessment time points, especially when combined with PLGA
as compared to pure PLGA. All tested polymers exhibited cell adhesion and proliferation.
However, PLGA-based biomaterials, especially when combined with rhGH, showed greater cell proliferation when the difference in growth from 24 to 72 hours was evaluated.
rhGH appeared to modify the polymer surface, with increased roughness and
microporosity. This feature was more evident in the PLGA+rhGH combination. Further
studies are required to clarify this potential for development of new biomaterials. / Biomateriais como alternativas ao osso aut?geno e outros tecidos biol?gicos, s?o muito
utilizados no tratamento de pacientes na rotina cir?rgica da regi?o maxilofacial. Neste
contexto, um biomaterial com caracter?sticas de arcabou?o (osteocondutor), e associado ?
um fator de crescimento (osteoindutor), seria de grande interesse para pesquisa e
aplica??o cl?nica. Pol?meros biodegrad?veis, utilizados para a libera??o lenta de
medicamentos, vem sendo estudados, demonstrando bons resultados e interessante
potencial. o rhGH pode ser liberado atrav?s da sua incorpora??o ? estes pol?meros.
Desta forma, se faz necess?rio a avalia??o da biocompatibilidade e toxicidade de um
biomaterial polim?rico para libera??o lenta do medicamento. Atrav?s da t?cnica de evapora??o de solvente foram preparados matrizes de PLGA e
PLGA/PCL na raz?o 70/30 de PLGA e PCL, respectivamente, associados ou n?o ao
rhGH. Os biomateriais foram testados relacionados ? sua toxicidade e viabilidade celular,
atrav?s de um ensaio de MTT com c?lulas de camundongo NIH 3T3 ATCC. A avalia??o
da toxicidade celular foi realizada nos tempos de 24 horas, 48 horas, 72 horas e 7 dias de
exposi??o dos biomateriais com o meio de cultura. Ap?s, os biomateriais foram testados
relacionados ? sua ades?o e prolifera??o celular, atrav?s do cultivo em c?lulas-tronco
mesenquimais de rato Wistar, com ensaio de colora??o DAPI e posterior contagem
celular, al?m de microscopia eletr?nica de varredura. A avalia??o da ades?o e
prolifera??o celular foi realizada nos tempos de 24 e 72 horas de exposi??o dos
biomateriais com o meio de cultura. Todos os pol?meros testados apresentaram altas taxas de viabilidade celular, por?m, os
grupos associados ao rhGH parecem demonstrar melhores resultados do que os grupos
de pol?meros sem associa??o ao horm?nio quando comparados ao grupo controle em
alguns per?odos do experimento. O que pode sugerir uma prefer?ncias das c?lulas ?
presen?a do rhGH no biomaterial presente no meio de cultura, principalmente na matriz de PLGA. Os pol?meros testados, apresentaram ades?o e prolifera??o celular, por?m, os
biomateriais ? base de PLGA, principalmente associados ao rhGH pareceram demonstrar
maior prolifera??o celular quando avaliada a diferen?a do crescimento de 24 para
72horas. O GH modificou a superf?cie do pol?mero, aumentando a rugosidade e
microporosidade. Aspecto visualizado principalmente quando incorporado ao PLGA. Mais
estudos s?o necess?rios para verificar alternativas de novos biomateriais para libera??o
lenta de f?rmacos.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/6678 |
| Date | 23 March 2016 |
| Creators | Gerzson, Alexandre da SIlveira |
| Contributors | Pagnoncelli, Rog?rio Miranda |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Odontologia, PUCRS, Brasil, Faculdade de Odontologia |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | -8096554818733665164, 600, 600, 600, 4673435736271820140, -2070498469879244349 |
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