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1.
Biomed Mater ; 15(5): 055013, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32252046

RESUMO

Osteoporotic bone defects are a major challenge in clinics for bone regeneration. With the condition of osteoporosis, excessive bone absorption and impaired osteogenesis result in unexpectedly long healing procedures for defects. In order to simultaneously enhance bone formation and reduce bone resorption, a polydopamine-coated porous titanium scaffold was designed, to be integrated with anti-catabolic drug zoledronic acid nanoparticles (ZOL loaded gelatin NPs), which was able to achieve a local sustained release of ZOL as expected. The in vitro study demonstrated that extracts of the composite scaffolds would stimulate osteoblast differentiation; they also inhibited osteoclastogenesis at a ZOL loading concentration of 50 µmol l-1. In the subsequent in vivo study, the composite scaffolds were implanted into ovariectomy-induced osteoporotic rabbits suffering from femoral condyles defects. The results indicated that the composite scaffolds without ZOL loaded gelatin NPs only induced callus formation, mainly at the interface margin between the implant and bone, whereas the composite scaffolds with ZOL loaded gelatin NPs were capable of further enhancing osteogenesis and bone growth into the scaffolds. Moreover, the research proved that the promoting effect was optimal at a ZOL loading concentration of 50 µmol l-1. In summary, the present research indicated that a new type of porous titanium scaffold integrated with ZOL loaded gelatin NPs inherited a superior biocompatibility and bone regeneration capability. It would be an optimal alternative for the reconstruction of osteoporosis-related defects compared to a traditional porous titanium implant; in other words, the new type of scaffold offers a new effective and practical procedure option for patients suffering from osteoporotic bone defects.

2.
Int J Nanomedicine ; 8: 1855-65, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23690683

RESUMO

PURPOSE: Poly(lactic-co-glycolic acid) (PLGA) is excellent as a scaffolding matrix due to feasibility of processing and tunable biodegradability, yet the virgin scaffolds lack osteoconduction and osteoinduction. In this study, nano-hydroxyapatite (nHA) was coated on the interior surfaces of PLGA scaffolds in order to facilitate in vivo bone defect restoration using biomimetic ceramics while keeping the polyester skeleton of the scaffolds. METHODS: PLGA porous scaffolds were prepared and surface modification was carried out by incubation in modified simulated body fluids. The nHA coated PLGA scaffolds were compared to the virgin PLGA scaffolds both in vitro and in vivo. Viability and proliferation rate of bone marrow stromal cells of rabbits were examined. The constructs of scaffolds and autogenous bone marrow stromal cells were implanted into the segmental bone defect in the rabbit model, and the bone regeneration effects were observed. RESULTS: In contrast to the relative smooth pore surface of the virgin PLGA scaffold, a biomimetic hierarchical nanostructure was found on the surface of the interior pores of the nHA coated PLGA scaffolds by scanning electron microscopy. Both the viability and proliferation rate of the cells seeded in nHA coated PLGA scaffolds were higher than those in PLGA scaffolds. For bone defect repairing, the radius defects had, after 12 weeks implantation of nHA coated PLGA scaffolds, completely recuperated with significantly better bone formation than in the group of virgin PLGA scaffolds, as shown by X-ray, Micro-computerized tomography and histological examinations. CONCLUSION: nHA coating on the interior pore surfaces can significantly improve the bioactivity of PLGA porous scaffolds.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos/farmacologia , Durapatita/farmacologia , Ácido Láctico/farmacologia , Nanocompostos/química , Ácido Poliglicólico/farmacologia , Tecidos Suporte/química , Animais , Substitutos Ósseos/química , Adesão Celular/efeitos dos fármacos , Durapatita/química , Histocitoquímica , Ácido Láctico/química , Modelos Biológicos , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Porosidade , Coelhos , Rádio (Anatomia)/química , Rádio (Anatomia)/diagnóstico por imagem , Rádio (Anatomia)/lesões , Rádio (Anatomia)/fisiologia , Microtomografia por Raio-X
3.
Biomaterials ; 34(9): 2234-43, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23294547

RESUMO

Clinical evidence indicates diabetes as a majorrisk factor for titaniumimplant treatment with high failure rates and poor osteointegration, but the underlying mechanism involved remains elusive.We hypothesize that reactive oxygen species (ROS) overproduction may contribute to the impaired osteogenesis of porous titanium implants (pTi) under diabetic conditions. To test this hypothesis, we culturedprimary rabbit osteoblasts onto pTi and studied the cellular performance when subjected to normal serum (NS), diabetic serum (DS), DS + NAC (a potent ROS inhibitor) and NS + H(2)O(2)(an oxidant).In-vivo performance of pTi was investigated by transplanting them intofemoral condyledefects of diabetic rabbits, which received vehicle or NAC treatment respectively.Results showed that diabetic conditions induced significant cellular apoptosis, depressedosteoblast function evidenced by impairedcell attachment and morphology, decreased cell proliferation anddifferentiation, andcompromised in-vivo osteogenesis ofpTi, while cellular ROSgeneration was increased derived from mitochondrial dysfunction. Scavenging ROS with NAC markedly attenuated cell apoptosis and osteoblast dysfunction, and improved bone ingrowth within pTi. Furthermore, treatment withH(2)O(2) exerted similar adverse effect on cellular behavior as diabetes. This study furthers our knowledge on the potential role of ROS overproduction in the diabetes-induced impaired osteogenesis of titanium implants, and indicates anti-oxidative treatment as a promising strategy to promote the treatment efficacy of pTi in diabetic patients.


Assuntos
Diabetes Mellitus/fisiopatologia , Osteogênese/fisiologia , Próteses e Implantes , Espécies Reativas de Oxigênio/metabolismo , Titânio/uso terapêutico , Fosfatase Alcalina/metabolismo , Animais , Apoptose , Caspase 3/genética , Caspase 3/metabolismo , Proliferação de Células , Peróxido de Hidrogênio/análise , Masculino , Mitocôndrias/metabolismo , Osteoblastos/citologia , Osteoblastos/fisiologia , Estresse Oxidativo , Porosidade , Coelhos , Substâncias Reativas com Ácido Tiobarbitúrico/análise
4.
Zhongguo Gu Shang ; 21(6): 438-40, 2008 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-19108429

RESUMO

OBJECTIVE: To investigate the pathogenesis and rehabilitative treatment for degeneration of cervical articular process. METHODS: Among 200 case of cervical disease with oblique radiography, 90 (45%) have different levels of facet degeneration, aged from 31 to 76 years, mostly in the elderly (accounting for 80%). There are no significant differences between men and women. RESULTS: There are three reasons for cervical facet degeneration. (1) Physiological degeneration of the articular process; (2) Acute and chronic injuries, especially whiplash injury; (3) Iatrogenic injury. Among these causes, iatrogenic injury is very common and has been neglected for a long time. When the intervertebral joint is instable, chronic fatigue or acute injury will certainly produce symptoms, including symptoms of nerve root type, or vertebral artery type, or both types of cervical disease. CONCLUSION: Oblique X-ray films show that superior articular process protrudes into the intervertebral foramen, which causes intervertebral foramen narrow, and the narrow degree is in proportion to rising and extending range of head and neck. Scientific and dialectical therapy is the key to treat this disease, and manipulative reduction to enlarging intervertebral foramen with the neck at flexing position is a targeted treatment, which can treat symptoms and causes of the disease at the same time. If the case is special, cervical dynamic extension and flexion X-ray film should be taken.


Assuntos
Vértebras Cervicais , Espondilose/reabilitação , Adulto , Idoso , Vértebras Cervicais/lesões , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Manipulação da Coluna , Pessoa de Meia-Idade , Espondilose/diagnóstico , Espondilose/etiologia
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