Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Indian J Ophthalmol ; 70(1): 201-209, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34937239

RESUMO

PURPOSE: There are no effective treatments currently available for optic nerve transection injuries. Stem cell therapy represents a feasible future treatment option. This study investigated the therapeutic potential of human umbilical cord-derived mesenchymal stem cell (hUC-MSC) transplantation in rats with optic nerve injury. METHODS: Sprague-Dawley (SD) rats were divided into three groups: a no-treatment control group (n = 6), balanced salt solution (BSS) treatment group (n = 6), and hUC-MSCs treatment group (n = 6). Visual functions were assessed by flash visual evoked potential (fVEP) at baseline, Week 3, and Week 6 after optic nerve crush injury. Right eyes were enucleated after 6 weeks for histology. RESULTS: The fVEP showed shortened latency delay and increased amplitude in the hUC-MSCs treated group compared with control and BSS groups. Higher cellular density was detected in the hUC-MSC treated group compared with the BSS and control groups. Co-localized expression of STEM 121 and anti-S100B antibody was observed in areas of higher nuclear density, both in the central and peripheral regions. CONCLUSION: Peribulbar transplantation of hUC-MSCs demonstrated cellular integration that can potentially preserve the optic nerve function with a significant shorter latency delay in fVEP and higher nuclear density on histology, and immunohistochemical studies observed cell migration particularly to the peripheral regions of the optic nerve.


Assuntos
Células-Tronco Mesenquimais , Traumatismos do Nervo Óptico , Animais , Potenciais Evocados Visuais , Humanos , Traumatismos do Nervo Óptico/terapia , Ratos , Ratos Sprague-Dawley , Cordão Umbilical
2.
Curr Eye Res ; 36(2): 88-93, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21281064

RESUMO

PURPOSE: To determine if microtopographical cues can influence the orientation and extracellular matrix production of human keratocytes in vitro. MATERIALS AND METHODS: Human keratocytes were cultured on grooved and ungrooved polycaprolactone films for up to 3 weeks. The cell morphology was examined using ordinary light microscopy, reflective microscopy, and scanning electron microscopy. The cells gene expression was examined using a GEArray Q series gene expression kit. RESULTS: Cells initially appeared to orientate in the direction of the grooves. Cells cultured on ungrooved films exhibited random orientations. For longer culture periods on grooved membranes, a second cell layer formed on top of the initial layer at an angle orientation to the initial layer. Analysis of mRNA showed that several genes involved in the production of integrins and matrix metalloproteinases were either up-regulated or down-regulated in the presence of the grooves. CONCLUSIONS: The introduction of microtopographical cues has been shown to influence the orientation of keratocytes and alter their gene expression. This pilot study reveals some important findings that can be used in the development of bioengineered corneas.


Assuntos
Polaridade Celular/fisiologia , Substância Própria/citologia , Sinais (Psicologia) , Proteínas do Citoesqueleto/genética , Proteínas do Olho/genética , Fibroblastos/citologia , Regulação da Expressão Gênica/fisiologia , Técnicas de Cultura de Células , Substância Própria/metabolismo , Topografia da Córnea , Proteínas do Citoesqueleto/metabolismo , Desmina/metabolismo , Proteínas do Olho/metabolismo , Fibroblastos/metabolismo , Perfilação da Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Microscopia Eletrônica de Varredura , RNA Mensageiro/genética , Doadores de Tecidos , Engenharia Tecidual , Vimentina/metabolismo
3.
Tissue Eng Part C Methods ; 16(2): 319-27, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19563255

RESUMO

Collagen hydrogels have been widely used to model biological systems and examine cell behavior in vitro. Of increasing interest is how cells affect the mechanical characteristics of their surrounding matrix and vice versa over long culture periods. In this study, the change in mechanical properties of collagen hydrogels embedded with human corneal fibroblasts was examined over a 6-week culture period using a novel online spherical indentation system. The elastic modulus of the hydrogels was found to increase during the first 2 weeks of culture and decrease after 4 weeks in culture. The effects of actin polymerization and matrix metalloproteinase inhibitors were also examined, which verified some mechanisms involved in the alteration of the mechanical properties such as cell tensile forces and other potential factors. This online monitoring technique demonstrates the ability to examine the mechanical properties of cell-seeded constructs in response to the culture environments--in particular, the response to the addition of drugs or chemical reagents--which will provide a useful tool in studying the mechano-feedback loop between cells and their surrounding matrix.


Assuntos
Colágeno/química , Córnea/fisiologia , Módulo de Elasticidade/fisiologia , Fibroblastos/fisiologia , Hidrogéis/química , Sistemas On-Line , Fenômenos Biomecânicos/fisiologia , Contagem de Células , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Córnea/citologia , Córnea/efeitos dos fármacos , Citocalasina D/farmacologia , Módulo de Elasticidade/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Humanos , Hidrogéis/farmacologia , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/métodos
4.
Ann Biomed Eng ; 35(9): 1608-16, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17479366

RESUMO

Cornea is a load-bearing tissue whose mechanical and viscoelastic characteristics are not well understood, due to the challenge associated with most of the measurements. A novel indentation technique has been developed for mechanical characterization of human and porcine corneal tissue, using a tailored depth-sensing microindentation instrument. During indentation, the corneas were suspended by clamping the edges of the cornea, thus allowing depth-sensing measurement free from the complication of the backing substrate. The deformation displacement and the amount of force applied by the indenter were used to obtain hysteresis and stress relaxation data for both human and porcine corneas. Optical coherence tomography was used to measure the thickness of the cornea. Simple theoretical analyses have been undertaken to explain the loading-unloading and the stress relaxation data. The effect of swelling on the mechanical properties of the cornea was also examined. Porcine corneas appeared to be less stiff and to demonstrate more linear response than human corneas under loading. More importantly, it is shown that swelling reduced the strength of the corneas. Our results demonstrate that this new indentation system can be used to characterize the mechanical and viscoelastic properties of corneas.


Assuntos
Córnea/fisiologia , Teste de Materiais/instrumentação , Sus scrofa/anatomia & histologia , Sus scrofa/fisiologia , Adulto , Idoso , Animais , Fenômenos Biomecânicos , Elasticidade , Feminino , Humanos , Teste de Materiais/métodos , Modelos Teóricos , Manejo de Espécimes/métodos , Tomografia/métodos , Viscosidade
5.
J R Soc Interface ; 2(5): 455-63, 2005 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-16849205

RESUMO

We present a novel indentation method for characterizing the viscoelastic properties of alginate and agarose hydrogel based constructs, which are often used as a model system of soft biological tissues. A sensitive long working distance microscope was used for measuring the time-dependent deformation of the thin circular hydrogel membranes under a constant load. The deformation of the constructs was measured laterally. The elastic modulus as a function of time can be determined by a large deformation theory based on Mooney-Rivlin elasticity. A viscoelastic theory, Zener model, was applied to correlate the time-dependent deformation of the constructs with various gel concentrations, and the creep parameters can therefore be quantitatively estimated. The value of Young's modulus was shown to increase in proportion with gel concentration. This finding is consistent with other publications. Our results also showed the great capability of using the technique to measure gels with incorporated corneal stromal cells. This study demonstrates a novel and convenient technique to measure mechanical properties of hydrogel in a non-destructive, online and real-time fashion. Thus this novel technique can become a valuable tool for soft tissue engineering.


Assuntos
Materiais Biocompatíveis/análise , Materiais Biocompatíveis/química , Testes de Dureza/instrumentação , Hidrogéis/análise , Hidrogéis/química , Modelos Químicos , Engenharia Tecidual/instrumentação , Técnicas de Cultura de Células/instrumentação , Técnicas de Cultura de Células/métodos , Simulação por Computador , Elasticidade , Desenho de Equipamento , Análise de Falha de Equipamento , Dureza , Testes de Dureza/métodos , Estimulação Física/instrumentação , Estimulação Física/métodos , Estresse Mecânico , Engenharia Tecidual/métodos , Viscosidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...