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1.
J Reconstr Microsurg ; 29(2): 77-87, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23203315

RESUMO

Nerve conduits have emerged as alternatives to autologous nerve grafts, but their use in large-diameter, critical nerve repairs is limited. In the previous study, we prepared a PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduit, which was made of RGD peptide modified poly{(lactic acid)-co-[(glycolic acid)-alt-(L-lysine)]} (PRGD), poly(d,l-lactic acid) (PDLLA), ß-tricalcium phosphate (ß-TCP) and nerve growth factor (NGF). Here we attempted to use the PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduit to bridge a 30-mm dog tibial nerve defect in six beagles. The other beagles were divided into group autograft (n = 6) as positive control and group PDLLA (n = 6) as negative control. After 9 months of implantation, nerve conduction velocities, the density of myelinated fibers, the mean diameter of axon, and the average thickness of myelin sheath in tibial nerves bridged with PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduits were similar to those treated with autologous nerve (p > 0.05). Neither electrophysiological nor histological restoration was obtained in group PDLLA. Evidence is thus provided in support of the use of PRGD/PDLLA/ß-TCP/NGF sustained-release nerve conduits as alternatives to autologous nerve grafts for treatment of large-diameter, critical defects in peripheral nerves.


Assuntos
Materiais Biocompatíveis/farmacologia , Lisina/farmacologia , Fator de Crescimento Neural/metabolismo , Condução Nervosa/fisiologia , Poliésteres/farmacologia , Nervo Tibial/fisiologia , Animais , Células Cultivadas , Preparações de Ação Retardada , Modelos Animais de Doenças , Cães , Estudos de Viabilidade , Masculino , Teste de Materiais , Fator de Crescimento Neural/farmacologia , Regeneração Nervosa , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Nervo Tibial/lesões , Nervo Tibial/transplante
2.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 34(5): 382-7, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19483284

RESUMO

OBJECTIVE: To investigate a new way to yield plenty of high purity olfactory ensheathing cells (OECs) and its biocompatibility with appropriate scaffolds. METHODS: OECs were prepared from neonatal Wister rats and co-cultured with poly [LA-co-(Glc-alt-Lys)] (PLGL). Its contact angle, adherent rate, and activity rate were tested. RESULTS: The contact angle of poly (D, L-lactic acid) (PDLLA) (84.5 degree+/-1.5 degree) was significantly higher than that of PLGL (52.6 degree+/-0.8 degree), the adherent rate of PLGL (80%) was significantly higher than that of the PDLLA (57%), and the activity rate of PLGL (88%) was much higher than that of the PDLLA (76%). CONCLUSION: PLGL possesses better hydrophilicity and biocompatibility than PDLLA, and it can provide a better cell growth circumstance which is helpful for the effective treatment of nerve injury.


Assuntos
Materiais Biocompatíveis , Ácido Láctico/farmacologia , Bulbo Olfatório/citologia , Ácido Poliglicólico/farmacologia , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Animais , Animais Recém-Nascidos , Células Cultivadas , Ácido Láctico/síntese química , Regeneração Nervosa , Ácido Poliglicólico/síntese química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Ratos , Ratos Wistar , Traumatismos da Medula Espinal/fisiopatologia
3.
J Biomed Mater Res A ; 107(11): 2414-2424, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31180606

RESUMO

Biomaterials can be used as carriers of antioxidant or drug to the oxidative injury site of tissue and decrease intracellular oxidative stress levels, however, low dosage delivery or unstable molecular structure of antioxidant or drug limited the long-term sustained release. A chemically stable antioxidant molecule is essential to serve as antioxidant structure components of biomaterials that may provide the relatively high antioxidant content and persisting local antioxidant release with the degradation of materials. In this study, we used citric acid modified polyvinyl alcohol (PVA-C) as a model biomaterial to investigate the role of citric acid on the material stimulated antioxidant and anti-inflammatory effects. In cellular-based assays, PVA-C extracts showed a protective effects on bone marrow mesenchymal stem cells (BMSCs) under oxidative stress. It could enhance the antiapoptotic ability of stem cells by inhibiting reactive oxygen species. Further studies revealed that PVA-C extracts upregulated the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) and superoxide dismutase [Mn] (SOD2). in vivo animal assays, PVA-C extracts showed significant inhibitory effects on the oxidative stress and inflammatory reaction which were induced by lipopolysaccharide (LPS). These findings suggest that the citric acid modified polymer can regulate the redox signaling of stem cells and tissues by the release of citric acid from materials, leading to enhanced oxidative stress-induced degenerative diseases and inflammatory diseases therapy.


Assuntos
Anti-Inflamatórios , Antioxidantes , Células da Medula Óssea/metabolismo , Ácido Cítrico , Células-Tronco Mesenquimais/metabolismo , Álcool de Polivinil , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Ácido Cítrico/química , Ácido Cítrico/farmacologia , Inflamação/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Álcool de Polivinil/química , Álcool de Polivinil/farmacologia , Ratos , Ratos Wistar , Espécies Reativas de Oxigênio/metabolismo
4.
Ultrason Sonochem ; 14(3): 286-90, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16904363

RESUMO

Stable hydroxyapatite (HAP) nanoparticles system was synthesized from Ca(H(2)PO(4))(2) aqueous solution and saturated Ca(OH)(2) aqueous solution by an improved precipitation method. This method was reformed through using ultrasound irradiation as assistant technology due to its unique chemical reaction effects and adding glycosaminoglycans (GAGs) as regulation additive due to its strong interaction with HAP. The products were characterized by Malvern Zetasizer 3000HS Analysis system, TEM and ED. The size distribution and zeta potential of HAP nanoparticles were influenced by the concentration of GAGs. With the GAGs concentration of 0.35g/L, the better excellent HAP nanoparticle system could be obtained with the number-averaged particle size of 22.2nm in 84.5% area and 54.6nm in 15.5% area between 18.1nm and 117.4nm and the zeta potential of -60.9mV. In the presence of GAGs, the particle size and size distribution are little sensitive to the ultrasound irradiation (UI) time. With the increasing of UI time from 0.5h to 3h and 5h, the particle size increased a little and the crystallinity was improved. GAGs inhibited HAP crystal growth and stabilized HAP nanoparticles. Based on the TEM observation and size distribution determination of HAP nanoparticles, the possible formation mechanism of HAP nanoparticles stabilized by GAGs under UI was discussed.


Assuntos
Durapatita/química , Glicosaminoglicanos/química , Nanopartículas/química , Sonicação , Materiais Biocompatíveis/química
5.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 23(2): 375-8, 2006 Apr.
Artigo em Zh | MEDLINE | ID: mdl-16706370

RESUMO

The PDLLA/HA compound fibers with excellent properties could be obtained by melt-spinning. This study inquired about the mechanical properties, change rule and influencing factors. The results showed that the composites fibers of mechanical properties were good in the PDLLA(molecular weight 120,000) to which were added the 4-20 microm HA particles. In the matrix of PDLLA with accretion (10%) of HA particles, the tensile strength of the compound fibers was the highest, compared with the others. The tensile strength of the compound fibers of PDLLA (molecular weight 20,000-300,000) was high. The tensile strength of the compound fibers decreased with the increase of the fiber diameter, and the PDLLA/HA fibers 40-60 micrometers in diameter had the highest elongation at break.


Assuntos
Substitutos Ósseos/química , Durapatita/química , Ácido Láctico/química , Polímeros/química , Engenharia Tecidual , Materiais Biocompatíveis/química , Poliésteres , Resistência à Tração , Engenharia Tecidual/métodos
6.
Biomed Mater Eng ; 15(5): 333-9, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-16179753

RESUMO

In this paper, preparation technologies for the compound fibers of poly D,L-lactic acid (PDLLA)/hydroxyapatite (HA) were investigated. Starting with PDLLA of weight average molecular mass 94,200-1,130,000 and HA powders of diameter 4-10 microm, the compound fibers of PDLLA/HA were obtained through a two stage process: first the adsorption of HA particles on the surface of PDLLA flakes using the liquid-phase adsorption method then melt-extrusion, and second the spinning collection. Experimental result was showed that the high performance composite fibers of PDLLA/HA with diameter of 15-30 micrometer could be produced by the PDLLA of weight average molecular mass 150,000-300,000, the HA powders content 5 wt%, the melt extrusion temperature below 160 degrees C and the screw rotating speed of 10-15 r/min, the spinning collection speed of 2-5 m/min.


Assuntos
Materiais Revestidos Biocompatíveis/química , Cristalização/métodos , Durapatita/química , Temperatura Alta , Ácido Láctico/química , Polímeros/química , Adsorção , Biotecnologia/métodos , Materiais Revestidos Biocompatíveis/análise , Durapatita/análise , Ácido Láctico/análise , Teste de Materiais , Tamanho da Partícula , Poliésteres , Polímeros/análise , Rotação , Têxteis/análise
7.
Biomaterials ; 55: 44-53, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25934451

RESUMO

Peripheral nerve injury requires optimal conditions in both macro-environment and micro-environment for reestablishment. Though various strategies have been carried out to improve the macro-environment, the underlying molecular mechanism of axon regeneration in the micro-environment provided by nerve conduit remains unclear. In this study, the rat sciatic nerve of 10 mm defect was made and bridged by PRGD/PDLLA nerve conduit. We investigated the process of nerve regeneration using histological, functional and real time PCR analyses after implantation from 7 to 35 days. Our data demonstrated that the ciliary neurotrophic factor highly expressed and up-regulated the downstream signaling pathways, in the case of activated signals, the expressions of axon sprout relative proteins, such as tubulin and growth-associated protein-43, were strongly augmented. Taken together, these data suggest a possible mechanism of axon regeneration promoted by PRGD/PDLLA conduit, which created a micro-environment for enhancement of diffusion of neurotrophic factors secreted by the injured nerve stumps, and activation of molecular signal transduction involved in growth cone, to potentiate the nerve recovery.


Assuntos
Regeneração Tecidual Guiada/instrumentação , Ácido Láctico/química , Regeneração Nervosa , Polímeros/química , Nervo Isquiático/patologia , Animais , Axônios/patologia , Materiais Biocompatíveis/química , Biomimética , Fator Neurotrófico Ciliar/metabolismo , Cistina/química , Proteína GAP-43/metabolismo , Regulação da Expressão Gênica , Regeneração Tecidual Guiada/métodos , Ligantes , Músculo Esquelético/inervação , Oligopeptídeos/química , Traumatismos dos Nervos Periféricos/terapia , Poliésteres/química , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Nervo Isquiático/efeitos dos fármacos , Transdução de Sinais , Tubulina (Proteína)/metabolismo
8.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 19(4): 552-5, 558, 2002 Dec.
Artigo em Zh | MEDLINE | ID: mdl-12561344

RESUMO

To evaluate the sealing potential of self-designed root canal filling material made of calcium phosphate cement (alpha-TCP/TTCP, CPC), the apices of root canals of six adult dogs were purposely perforated and enlarged up to the No 40 instrument. Then CPC was used to fill the root canal. Mean while either calcium hydroxide (Ca(OH)2) paste or hydroxyapatite (HA) paste was used as control. The animals were killed at 4, 12, 20 weeks postoperatively. The different materials about ways of apical closure, restoration periapocal tissues and adaptability to the dentinal surface were observed by histomorphology and scanning electron microscopic. This study revealed that CPC had excellent biocompatibility and adaptability to the dentinal wall. Its osteoconduction can promote the formation of calcific barriers and healing of periapical tissue. The apex can be closed completely. Compared with the control pastes it has advantages of ease of manipulation and better sealing capability. The results showed that CPC could be used as a root canal filling material for pupless teeth with open apex and destructive periapical tissue.


Assuntos
Fosfatos de Cálcio/farmacologia , Materiais Restauradores do Canal Radicular/farmacologia , Animais , Cães , Tratamento do Canal Radicular
9.
J Biomed Mater Res A ; 102(10): 3734-43, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24408878

RESUMO

A novel nerve guidance conduit comprising poly{(lactic acid)-co-[(glycolic acid)-alt-(l-lysine)]} (PRGD), poly (d,l-lactic acid) (PDLLA) and ß-tricalcium phosphate (ß-TCP) was constructed to facilitate the peripheral nerve regeneration. From the comparative study, PDLLA/PRGD/ß-TCP conduit achieved the best recovery in regard of the ultrastructure observation and the SFI evaluation. At the first stage of the injury (7 days), the maximum expression augments in ZnSOD (6.4 folds) and GPX4 (6.8 folds) were observed in PDLLA/PRGD/ß-TCP group; while striking rise in actin (6.8 folds), tubulin (5.6 folds), and ERM components expressions were observed later (35 days). Meanwhile, compared with PDLLA and PDLLA/PRGD conduits, PDLLA/PRGD/ß-TCP conduits achieved the highest local nerve growth factor (NGF) content and an accumulating BDNF content. We speculated that addition of RGD and ß-TCP in the composites were the main positive factors to build the microenvironment rich in NGF and BDNF, which help to counteract with the oxidative stress and to boost the cytoskeletal protein expressions. Therefore, PDLLA/PRGD/ß-TCP could be promising composites used in peripheral nerve regeneration.


Assuntos
Fosfatos de Cálcio/farmacologia , Ácido Láctico/farmacologia , Lisina/farmacologia , Fator de Crescimento Neural/farmacologia , Regeneração Nervosa/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Poliésteres/farmacologia , Polímeros/farmacologia , Nervo Isquiático/fisiopatologia , Animais , Microambiente Celular/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Regeneração Tecidual Guiada , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Nervo Isquiático/patologia , Nervo Isquiático/cirurgia , Nervo Isquiático/ultraestrutura
10.
Biomaterials ; 35(1): 225-35, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24138830

RESUMO

The significant drawbacks and lack of success associated with current methods to treat critically sized nerve defects have led to increased interest in neural tissue engineering. Conducting polymers show great promise due to their electrical properties, and in the case of polypyrrole (PPY), its cell compatibility as well. Thus, the goal of this study is to synthesize a conducting composite nerve conduit with PPY and poly(d, l-lactic acid) (PDLLA), assess its ability to support the differentiation of rat pheochromocytoma 12 (PC12) cells in vitro, and determine its ability to promote nerve regeneration in vivo. Different amounts of PPY (5%, 10%, and 15%) are used to synthesize the conduits resulting in different conductivities (5.65, 10.40, and 15.56 ms/cm, respectively). When PC12 cells are seeded on these conduits and stimulated with 100 mV for 2 h, there is a marked increase in both the percentage of neurite-bearing cells and the median neurite length as the content of PPY increased. More importantly, when the PPY/PDLLA nerve conduit was used to repair a rat sciatic nerve defect it performed similarly to the gold standard autologous graft. These promising results illustrate the potential that this PPY/PDLLA conducting composite conduit has for neural tissue engineering.


Assuntos
Ácido Láctico , Regeneração Nervosa , Polímeros , Pirróis , Animais , Microscopia Eletrônica de Varredura , Tamanho do Órgão , Células PC12 , Poliésteres , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Espectroscopia de Infravermelho com Transformada de Fourier , Caminhada
11.
Biomaterials ; 32(20): 4506-16, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21397324

RESUMO

Biodegradable PDLLA/Chondroitin sulfate/Chitosan(PDLLA/CS/CHS) nerve conduits with potentially good biocompatibility and good mechanical property feasible for surgical manipulation have been developed in our previous work. The purpose of this study was to investigate their possible application in repairing damaged nerves and the effect of nerve growth factor (NGF). The PDLLA/CS/CHS/NGF nerve conduits were prepared by immobilizing NGF onto the PDLLA/CS/CHS nerve conduits with carbodiimide. Adult Sprague-Dawley (SD) rats weighing 200-250 g were used as the animal model. The conduits were employed to bridge the 10 mm defects in the sciatic nerve of the SD rats. Nerve conduction velocities (NCVs) were clearly detected in both nerve conduits after 3 months of implantation, indicating a rapid functional recovery for the disrupted nerves. The results of histological sections showed that the internal sides of the conduits were compact enough to prevent the connective tissues from ingrowth. Combined with the strong mechanical properties, good nerve regeneration ability and non-toxicity of its degradation products, PDLLA/CS/CHS nerve conduits would be expected to be useful materials to repair nerve damage and NGF can effectively promote the regeneration of peripheral nerve defect.


Assuntos
Materiais Biocompatíveis , Quitosana , Sulfatos de Condroitina , Ácido Láctico , Regeneração Nervosa/fisiologia , Nervos Periféricos/fisiologia , Polímeros , Alicerces Teciduais/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Quitosana/química , Quitosana/metabolismo , Sulfatos de Condroitina/química , Sulfatos de Condroitina/metabolismo , Ácido Láctico/química , Ácido Láctico/metabolismo , Teste de Materiais , Fator de Crescimento Neural/metabolismo , Condução Nervosa/fisiologia , Nervos Periféricos/citologia , Nervos Periféricos/patologia , Poliésteres , Polímeros/química , Polímeros/metabolismo , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/citologia , Nervo Isquiático/patologia , Nervo Isquiático/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier
12.
Biomed Mater ; 4(3): 035008, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19468157

RESUMO

To prepare one electroactive and biodegradable biomaterial for biomedical application, a new synthetic strategy was developed to synthesize a novel electrically conductive biodegradable polyphosphazene polymer containing parent aniline pentamer (PAP) and glycine ethyl ester (GEE) as side chains by a nucleophilic substitution reaction. The electrical conductivity of the polymer is approximately 2 x 10(-5) S cm(-1) in the semiconducting region upon preliminarily protonic-doped experiment. The degradation and RSC96 Schwann cells experiments in vitro prove that the polymer is biodegradable and beneficial to the cell adhesion and proliferation. The as-synthesized polymer also shows good solubility in common organic solvent and good film-forming properties. This new type of polymer has potential applications as scaffolds for neuronal and cardiovascular tissue engineering or other biomedical devices that require electroactivity.


Assuntos
Implantes Absorvíveis , Materiais Biocompatíveis/química , Compostos Organofosforados/química , Polímeros/química , Células de Schwann/citologia , Células de Schwann/fisiologia , Engenharia Tecidual/métodos , Adesão Celular , Técnicas de Cultura de Células/métodos , Proliferação de Células , Células Cultivadas , Condutividade Elétrica
13.
Biomed Mater ; 1(3): 124-6, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18458392

RESUMO

The static friction behavior between a porous bioceramic material and an intestinal mucus film was investigated in order to develop a new intestine robotic endoscope. Here, the friction couple is porous beta-tricalcium phosphate (beta-TCP) and an artificial intestine mucus film. The effect of pore size of the beta-TCP material on the friction behavior is investigated. The results illustrated that in this friction system there is a relatively small normal force upon the intestinal mucus film of the intestine wall during locomotion. The maximum static friction force in this friction couple varies with the pore size of the porous beta-TCP material.


Assuntos
Materiais Biocompatíveis/química , Materiais Biomiméticos/química , Fosfatos de Cálcio/química , Cerâmica/química , Mucosa Intestinal/fisiologia , Modelos Biológicos , Animais , Simulação por Computador , Fricção , Humanos , Teste de Materiais , Membranas/fisiologia , Porosidade , Estresse Mecânico
14.
Artigo em Inglês | MEDLINE | ID: mdl-15508278

RESUMO

This article describes the immobilization of cholesterol oxidase on a cellulose acetate (CA) membrane activated by Sodium periodate, ethylenediamine, and glutaraldehyde etc. The properties of the immobilized enzyme membrane were investigated. The factors affecting the activity of immobilized enzyme such as the concentration of glutaraldehyde, the concentration of enzyme used during immobilization, temperature, pH, and immobilizing time etc. were also studied. The immobilized COD membrane has been used to construct fibre-optic fluorescent biosensor.


Assuntos
Técnicas Biossensoriais/métodos , Celulose/análogos & derivados , Celulose/química , Colesterol Oxidase/química , Colesterol/análise , Enzimas Imobilizadas/química , Reagentes de Ligações Cruzadas/química , Estabilidade Enzimática , Tecnologia de Fibra Óptica , Fluorescência , Membranas Artificiais
15.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 38(6): 452-4, 2003 Nov.
Artigo em Zh | MEDLINE | ID: mdl-14703483

RESUMO

OBJECTIVE: To investigate the applicability of PDLLA/nano-HA compound plates used in internal fixation of mandibular fractures. METHODS: Rabbit mandibular fracture model was used in this study. Clinical observation, the amount of callus, histological observation were studied and compared with PDLLA plates. RESULTS: All fractures were fixed rigidly. There was 1 animal experienced local inflammation and then forming fistula in the side of PDLLA plate at postoperative 2 and 3 weeks. No side-effects were found in the side of compound plates. During the early stage of bone healing, the quality of callus in the side of compound plates was apparently more than that in the other side, and histological study showed that the osteoblasts and fibroblasts were more active in the side of compound plate in the early healing stage. CONCLUSIONS: PDLLA/nano-HA compound plate has a proper degradation time. Compared with PDLLA plates, it is more effective and safer when used in mandibular fracture.


Assuntos
Placas Ósseas , Fixação Interna de Fraturas/métodos , Fraturas Mandibulares/cirurgia , Animais , Durapatita , Masculino , Poliésteres , Coelhos
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