Análise da reparação de fraturas em fêmures de ratas osteoporóticas em função de placas de fixação submetidas ao método de texturização por plasma eletrolítico e incorporação de íons cálcio e fósforo.
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2020-09-02
Autores
Barbosa, Stéfany [UNESP]
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Universidade Estadual Paulista (Unesp)
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O objetivo do presente trabalho foi analisar o potencial osteocondutor de miniplacas com texturização de superfície por meio da oxidação por plasma eletrolítico, no reparo ósseo de fraturas femorais simuladas em ratas osteoporóticas. Para tanto, 24 ratas Wistar, fêmeas, com 6 meses de idade, foram submetidas à ovariectomia bilateral (OVX) e mais 24 passaram por cirurgia fictícia de ovariectomia (SHAM), totalizando uma amostra de 48 animais. Após um período de 3 meses de proservação para indução de osteoporose, seguiu-se com osteotomia para confecção de fratura em ambos os fêmures e fixação com miniplacas e parafusos do sistema 1,5mm, sendo metade da amostra fixada com miniplacas texturizadas pela oxidação por plasma eletrolítico (PEO) (grupo experimental) e a outra metade com miniplacas superfície usinada (CONV) (grupo controle). Nos períodos de 14 e 42 dias pós-operatório realizou-se aplicação dos fluorocromos calceína e alizarina, respectivamente. A eutanásia de todos os animais foi realizada aos 60 dias pós-operatória, com coleta dos fêmures, coleta de sangue para dosagem de estrógeno e biópsia de órgãos de metabolização. Os fêmures foram encaminhadas para o processamento laboratorial para escaneamento em microtomografia computadorizada para avaliação volumétrica (BV/TV) e de qualidade óssea (Tb.Th, Tb.Sp e Tb.N), escaneamento por microscopia confocal a laser, análise histométrica e análise biomecânica. Além disso, no período baseline, realizou-se Microscopia Eletrônica de Varredura (MEV) e Espectroscopia de Energia Dispersiva (EDS) para observação dos efeitos superficiais do tratamento. A caracterização da superfície evidenciou a distribuição homogênea de poros semelhantes a vulcões por toda a miniplaca. A partir da microtomografia computadorizada observou-se que o grupo OVX/PEO obteve maior valor para os parâmetros Tb.Th, Tb.N e Tb.Sp quando comparado ao grupo OVX/CONV. A análise histométrica constatou formação óssea mais significante para o grupo OVX/PEO, do que o obtido pelo grupo OVX/CONV (p<0,05- Teste de Tukey). Em relação a área de fluorocromo, houve uma maior precipitação de calceína do que de alizarina para os grupos OVX (PEO e CONV). OVX/PEO demonstrou ainda, maiores valores de resiliência óssea em relação aos outros grupos (P<0,05). Conclui-se que a texturização por PEO leva a uma otimização do reparo ósseo em fraturas femorais de ratas osteoporóticas.
The objective of the present work was to analyze the osteoconductive potential of miniplates with surface coating by means of plasma electrolytic oxidation, in the bone repair of simulated femoral fractures in osteoporotic rats. Therefore, 24 female Wistar rats, 6 months old, were submitted to bilateral ovariectomy (OVX) and another 24 underwent fictitious ovariectomy surgery (SHAM), totaling a sample of 48 animals. After a period of 3 months of proservation to induce osteoporosis, an osteotomy for femoral fractures design was performed in both femurs and fixation with 1.5mm mini-plates and screws, half of the sample fixed with mini-plates textured by plasma oxidation electrolytic (PEO) (experimental group) and the other half with machined surface mini plates (CONV) (control group). In the periods of 14 and 42 days postoperatively, the fluorochromes calcein and alizarin were applied, respectively. The euthanasia of all animals was performed at 60 days postoperatively, with collection of femurs, collection of blood for estrogen measurement and biopsy of metabolizing organs. The femurs were sent to laboratory processing for scanning using computerized microtomography for volumetric (BV / TV) and bone quality assessment (Tb.Th, Tb.Sp and Tb.N), scanning by laser confocal microscopy, histometric analysis and biomechanics analysis. In addition, in the baseline period, Scanning Electron Microscopy (SEM) and Dispersive Energy Spectroscopy (EDS) were performed to observe the surface effects of the treatment. The characterization of the surface showed the homogeneous distribution of pores like volcano throughout the miniplate. From the computed microtomography, it was observed that the OVX / PEO group obtained a higher value for the parameters Tb.Th, Tb.N and Tb.Sp when compared to the OVX / CONV group. The Histometric analysis found greater bone formation for OVX / PEO group when compared to OVX / CONV group (P <0.05 - Tukey test). Regarding the fluorochrome area, there was a greater precipitation of calcein than of alizarin for the OVX groups (PEO and CONV). The OVX / PEO also demonstrated higher bone turnover values in relation to the other groups (P <0.05). It is concluded that PEO coating leads to an optimization of bone repair in femoral fractures of osteoporotic rats.
The objective of the present work was to analyze the osteoconductive potential of miniplates with surface coating by means of plasma electrolytic oxidation, in the bone repair of simulated femoral fractures in osteoporotic rats. Therefore, 24 female Wistar rats, 6 months old, were submitted to bilateral ovariectomy (OVX) and another 24 underwent fictitious ovariectomy surgery (SHAM), totaling a sample of 48 animals. After a period of 3 months of proservation to induce osteoporosis, an osteotomy for femoral fractures design was performed in both femurs and fixation with 1.5mm mini-plates and screws, half of the sample fixed with mini-plates textured by plasma oxidation electrolytic (PEO) (experimental group) and the other half with machined surface mini plates (CONV) (control group). In the periods of 14 and 42 days postoperatively, the fluorochromes calcein and alizarin were applied, respectively. The euthanasia of all animals was performed at 60 days postoperatively, with collection of femurs, collection of blood for estrogen measurement and biopsy of metabolizing organs. The femurs were sent to laboratory processing for scanning using computerized microtomography for volumetric (BV / TV) and bone quality assessment (Tb.Th, Tb.Sp and Tb.N), scanning by laser confocal microscopy, histometric analysis and biomechanics analysis. In addition, in the baseline period, Scanning Electron Microscopy (SEM) and Dispersive Energy Spectroscopy (EDS) were performed to observe the surface effects of the treatment. The characterization of the surface showed the homogeneous distribution of pores like volcano throughout the miniplate. From the computed microtomography, it was observed that the OVX / PEO group obtained a higher value for the parameters Tb.Th, Tb.N and Tb.Sp when compared to the OVX / CONV group. The Histometric analysis found greater bone formation for OVX / PEO group when compared to OVX / CONV group (P <0.05 - Tukey test). Regarding the fluorochrome area, there was a greater precipitation of calcein than of alizarin for the OVX groups (PEO and CONV). The OVX / PEO also demonstrated higher bone turnover values in relation to the other groups (P <0.05). It is concluded that PEO coating leads to an optimization of bone repair in femoral fractures of osteoporotic rats.
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Palavras-chave
Osteoporose, Regeneração óssea, Titânio, Osteoporosis