RESUMO
Electrospun ultrathin fibrous scaffold filed with synthetic nanohydroxyapatite (nHAp) and graphene nanoribbons (GNR) has bioactive and osteoconductive properties and is a plausible strategy to improve bone regeneration. Poly(butylene-adipate-co-terephthalate) (PBAT) has been studied as fibrous scaffolds due to its low crystallinity, faster biodegradability, and good mechanical properties; however, its potential for in vivo applications remains underexplored. We proposed the application of electrospun PBAT with high contents of incorporated nHAp and nHAp/GNR nanoparticles as bone grafts. Ultrathin PBAT, PBAT/nHAp, and PBAT/nHAp/GNR fibers were produced using an electrospinning apparatus. The produced fibers were characterized morphologically and structurally using scanning electron (SEM) and high-resolution transmission electron (TEM) microscopies, respectively. Mechanical properties were analyzed using a texturometer. All scaffolds were implanted into critical tibia defects in rats and analyzed after two weeks using radiography, microcomputed tomography, histological, histomorphometric, and biomechanical analyses. The results showed through SEM and high-resolution TEM characterized the average diameters of the fibers (ranged from 0.208 µm ± 0.035 to 0.388 µm ± 0.087) and nHAp (crystallite around 0.28, 0.34, and 0.69 nm) and nHAp/GNR (200-300 nm) nanoparticles distribution into PBAT matrices. Ultrathin fibers were obtained, and the incorporated nHAp and nHAp/GNR nanoparticles were well distributed into PBAT matrices. The addition of nHAp and nHAp/GNR nanoparticles improved the elastic modulus of the ultrathin fibers compared to neat PBAT. High loads of nHAp/GNR (PBATnH5G group) improved the in vivo lamellar bone formation promoting greater radiographic density, trabecular number and stiffness in the defect area 2 weeks after implantation than control and PBAT groups.
RESUMO
Objetivo: Dados estatísticos nacionais e mundiais demonstram que o número de indivíduos idosos tende a crescer de maneira exponencial nos próximos anos, tornando-se uma população significativamente e proporcionalmente maior que as demais. Entre as doenças mais comuns nessa faixa estaria encontra-se a osteoporose, doença que reduz a massa esquelética e deteriora a microarquitetura do osso causando fragilidade e aumentando o risco de fraturas. Material e Métodos: Este estudo teve como proposta avaliar o efeito da Arnica montana fitoterápica e homeopática no reparo de lesões ósseas, visando uma possível forma de tratamento de fraturas na vigência da osteoporose. Os ensaios experimentais foram realizados em ratas Wistar adultas, divididas em quatro grupos: ovariectomizado tratado com Arnica montana 6CH homeopática (OVZ 6CH); ovariectomizado tratado com extrato fitoterápico de Arnica montana (OVZ TM); ovariectomizada tratado com placebo (OVZ PL) falsa cirurgia de ovariectomia e tratado com placebo (Sham PL). Após 45 dias da cirurgia sham ou de ovariectomia, foi realizada uma lesão óssea monocortical. Os animais foram eutanasiados após 6, 12, 18 e 28 dias e as tíbias retiradas para avaliação das suas dimensões e analise do reparo ósseo através de densidade óssea radiográfica, ensaios biomecânicos e microscopia eletrônica de varredura (MEV). Os dados do teste de flexão foram submetidos à analise estatística pelos testes de ANOVA e Tukey (p< 5%). Resultados: Conclui-se que o tratamento com arnica 6CH foi melhor que o com arnica TM quanto à resistência e à qualidade de regeneração óssea, enquanto a TM mostrou melhor valor de densidade óptica. Conclusão: Esse estudo concluiu que o tratamento com Arnica montana homeopática foi mais eficiente que com Arnica fitoterápica na regeneração óssea de ratas com osteoporose (AU)
Objective: National and international data show that in the next years the elder population tends to have an exponential increase becoming to be significantly higher than other ages. Among the frequent diseases in the elderly, osteoporosis is a disease that decreases bone mass and deteriorates bone structure causing fragility and a high risk of fracture. This study aimed to evaluate the effect of phytotherapic and homeopathic Arnica montana on bone repair quality and its possible use in the treatment of bone fracture in patients with osteoporosis. Material and Methods: This experimental study was performed in Wistar adult female rats divided in 4 groups according to the following treatments: ovariectomized treated with homeopathic A. montana 6CH (OVZ 6CH); ovariectomized treated with phytotherapic A. montana (OVZ TM); ovariectomized with placebo (OVZ PL) and rats with sham surgery and placebo (Sham PL). In a period of 45 days after ovariectomy or sham surgery, all animals got a monocortical lesion. They were euthanized after 6, 12, 18 and 28 days and had the tibiae removed to evaluate dimensions and bone repair by radiographic density, biomechanical test and scanning electronic microscopy (SEM). Data were analyzed by ANOVA and TUKEY tests (p < 0.05). Results: Results showed that treatment with Arnica 6CH was better than Arnica TM considering bone resistance and bone repair quality. Conclusion: This study concluded that treatment with homeopathic A. montana was more efficient than with phytotherapic Arnica in bone regeneration in rats with osteoporosis.(AU)
