ABSTRACT
O objetivo detse artigo é de descrever um protocolo de isolamento das células mononucleares da medula óssea de coelhos, seguido de purificação celular por depleção negativa com o anticorpo monoclonal CD45 e posterior expansão em meio de cultura MesenCult®. Dez coelhos machos adultos, da raça Nova Zelândia, com idade média de 1,0±0,2 anos e peso médio 3,5±0,24kg, foram utilizados para padronização da metodologia. O isolamento das células mononuclares da medula óssea foi realizado pelo gradiente de densidade Ficoll-paque® e a purificação e obtenção das células- pela depleção negativa com o anticorpo monoclonal CD45 em base imunomagnética. A população celular obtida foi expandida posteriormente em meio de cultura MesenCult®. No isolamento pelo gradiente de icoll-Paque® foi obtido um rendimento médio de 7,31x106 células/mL. Após purificação e obtenção das possíveis células-tronco mesenquimais pela base imunomagnética, houve um decréscimo do rendimento para 2,28x106 células/mL, mas o processo de expansão foi incrementado pelo cultivo celular. Os resultados indicaram que as células obtidas da fração mononuclear da medula óssea, cultivadas in vitro foram capazes de gerar células aderentes 24 horas após o cultivo, com predominância de células fibroblastóides sugestivas de células-tronco mesenquimais. Concluiu-se que a obtenção de células-tronco mesenquimais pode ser alcançada após purificação das células mononucleares da medula óssea de coelhos pelo método imunomagético, o meio de cultura MesenCult® proporciona um ambiente adequado para a rápida expansão in vitro e o número de passagens exerce influência negativa sobre as características morfológicas das células.
The objective of this study was to describe guidelines for the isolation of bone marrow mononuclear cells from rabbits, followed by cell purification by negative depletion with CD45 monoclonal antibody, and further expansion in MesenCult® medium. Ten adult male New Zealand White rabbits, age average of 1.0±0.2 years and weighting 3.5±0.24kg, were used to obtain a standardized method. The mononuclear cells of the bone marrow were isolated with Ficoll-paque® density gradient centrifugation, and the cell purification and acquisition was completed by negative depletion with CD45 monoclonal antibody in immunomagnetic base. The cell population obtained was expanded in MesenCult® medium. Through isolation with Ficoll-paque® density gradient was possible to obtain an average yield of 7.31x106 cells/mL. After purification and acquisiton of potential mesenchymal stem cells by the immunomagnetic base, there was a yield decrease to 2.28x106 cells/mL; however the expansion process was increased in cell culture. The results indicated that cells obtained from the mononuclear fraction of bone marrow and cultivated in vitro were capable to generate adherent cells 24 hours after culture, with predominance of fibroblastoid cells suggestive of mesenchymal stem cells. It can be concluded that mesenchymal stem cells can be achieved with purified rabbit bone marrow mononuclear cells through the immunomagnetic method, as the MesenCult® medium provides a suitable environment for a quick in vitro expansion, and the number of passages exerts negative influence on the morphological characteristics.
Subject(s)
Animals , Male , Rabbits , Adult Stem Cells , Antibodies, Monoclonal/analysis , Bone Marrow Cells , Cell Separation/veterinary , Lagomorpha , Immunomagnetic Separation/veterinary , In Vitro Techniques/veterinaryABSTRACT
O interesse nas pesquisas com células-tronco derivadas de anexos fetais de diversas espécies cresceu exponencialmente nas últimas décadas em virtude de serem fontes de células-tronco adultas com potencial de diferenciação em diversas linhagens celulares que apresentam pouca ou nenhuma imunogenicidade, apresentando-se assim como alternativa de grande importância para a formação de bancos celulares. Apesar do crescente interesse, os estudos para espécie equina ainda são escassos. O objetivo deste trabalho foi isolar, caracterizar e diferenciar células-tronco mesenquimais (CTMs) derivadas do líquido amniótico equino obtidas do terço inicial, médio e final da gestação (LA-CTMs), comparando suas características. Foram colhidas 23 amostras de líquido amniótico as quais foram submetidas às análises morfológica, imunocitoquímica, imunofenotípica por citometria de fluxo e às diferenciações osteogênica, adipogênica e condrogênica in vitro. Todas as amostras demonstraram adesão ao plástico e morfologia fibroblastóide. No ensaio imunocitoquímico as células de todos os grupos foram imunomarcadas para CD44, PCNA e vimentina com ausência de marcação para citoqueratina e Oct-4. Na citometria de fluxo observou-se a expressão de CD44 e CD90 e ausência de expressão de CD34, sendo que os marcadores CD44 e CD90 mostraram padrão de expressão decrescente em relação ao desenvolvimento gestacional. As amostras obtidas de todas as fases da gestação foram capazes de diferenciação nas linhagens osteogênica, condrogênica e adipogênica. Portanto, as células obtidas do líquido amniótico apresentaram características morfológicas, imunofenotípicas e potencial de diferenciação típicos das CTMs, demonstrando que a colheita pode ser realizada em qualquer fase gestacional. No entanto, mais pesquisas devem ser realizadas principalmente quanto à expressão de marcadores de pluripotencialidade (como o Oct-4) e ao seu potencial de diferenciação em linhagens extra mesodermais já relatados na literatura.
The interest in stem cells derived from fetal annexes of many species has exponentially increased during the last decades, because they are adult stem cell sources with potential of differentiation in several cell lineages; which present little or no immunogenicity and are an alternative with great importance for storage cell banks. Despite the rising interest, studies for the equine species are still rare. The aim of this study was to isolate, characterize and differentiate mesenchymal stem cells derived from equine amniotic fluid obtained from initial, middle and late third of gestation (AF-MSCs), and compare their results. Twenty three samples from equine amniotic fluid were evaluated by morphological, immunocytochemical and immunophenotypical (Flow cytometer) assays and osteogenic, adipogenic and chondrogenic in vitro differentiation. All samples demonstrated plastic adhesion and fibroblastoid morphology. The immunocytochemical assay demonstrated cells from all the studied groups were positive for CD44, PCNA and vimentin and negative for cytokeratin and Oct-4. Flow cytometry demonstrated expression of CD44 and CD90 and no expression of CD34, where CD44 and CD90 markers presented decreasing pattern of expression in relation to the gestational development. All samples collected from all gestational phases were capable to differentiate in osteogenic, chondrogenic and adipogenic lineages. Thus, cells obtained from equine amniotic fluid presented morphological and immunophenotypical characteristics and potential of differentiation typical of MSCs showing that the collection can be performed at any stage of pregnancy. However, more studies should be performed about the expression of pluripotent markers as Oct-4 and the differentiation potential for extra mesodermal lineages prior demonstrated in the literature.
Subject(s)
Animals , Female , Horses/physiology , Stem Cells/physiology , Fibroblasts/physiology , Immunohistochemistry , Amniotic Fluid/chemistry , Cell Separation/veterinary , Mesenchymal Stem Cell Transplantation/veterinaryABSTRACT
The objective of this study was to characterize acrosomal ultrastructure following discontinuous Percoll gradient centrifugation of cryopreserved bovine sperm. Semen was collected from six bulls of different breeds and three ejaculates per bull were evaluated. Frozen semen samples were thawed and the acrosomal region of sperm cells was evaluated by transmission electron microscopy (TEM) before (n = 18) and after (n = 18) Percoll centrifugation. The evaluation of 20 sperm heads from each of the 36 samples analyzed ensured that a large number of cells were investigated. The data were subjected to analysis of variance at a level of significance of 5%. Percoll centrifugation reduced the percentage of sperm exhibiting normal acrosomes (from 61.77 to 30.24%), reduced the percentage of sperm presenting atypical acrosome reactions (from 28.38 to 4.84%) and increased the percentage of sperm exhibiting damage in the acrosome (from 6.14 to 64.26%). The percentage of sperm with typical acrosome reactions was not significantly different before (3.70%) and after (0.67%) centrifugation. TEM distinguished four different types of acrosomal status and enabled ultrastructural characterization of acrosomal injuries. The percentage of sperm exhibiting normal acrosomes decreased and damage in the acrosome was the most frequent acrosomal injury with the Percoll gradient centrifugation protocol utilized.