Isolation, expansion, differentiation and growth kinetics essay in mesenchymal stem cells culture from the bone marrow of collared peccaries (Tayassu tajacu)

Background: There are few studies on stem cell isolation in wild animals that provide isolation and culture protocols of these cells in vitro. Among the wild species studied, we present the collared peccary (Tayassu tajacu) as a model with potential to obtain and use MSC in preclinical studies. These animals are phylogenetically close to the domestic pig, popularly known as peccaries and found naturally in South America, Central America and the South of the United States. The aim of the present study was to establish a protocol for the isolation, in vitro cell expansion, differentiation and assessment of the stromal MSC growth curve before and after thawing. Materials, Methods & Results: Mesenchymal stem cells (MSC) from collared peccary bone marrow (Tayassu tajacu) were isolated and expanded by centrifuge in Ficoll® solution and cultured in DMEM® High Glucose medium. The culture was assessed by assays of colony forming units CFU-F and growth curve by saturation (GCS). Cultures in the third passage, with 70% confluence, were replicated at 105 cells/mL concentration in the culture media to induce osteogenic cell differentiation and adipogenic cell differentiation, respectively. The MSC were frozen in nitrogen for 40 days, thawed and re-assessed for cell viability and GCS. Discussion: The bone marrow collected presented high mononuclear cellularity, with a mean variability of 94.5% and 60.83 ± 4.27 UFC were identified in the samples and cells with fibroblast-like-cell morphology were observed. When they were expanded, the mean cell viability was 95%, the mean cell concentration obtained was 233.31 ± 20.04 cells per 25cm2 bottle and the culture reached the growth plateau in GCS between the 13th and 16th day. The osteoblastic cell differentiation assay showed after 18 days, morphology similar to osteoblasts, with irregular cytoplasm limits, cell prolongation formation and flattened appearance. [...](AU)

Isolation, expansion, differentiation and growth kinetics essay in mesenchymal stem cells culture from the bone marrow of collared peccaries (Tayassu tajacu)

Background: There are few studies on stem cell isolation in wild animals that provide isolation and culture protocols of these cells in vitro. Among the wild species studied, we present the collared peccary (Tayassu tajacu) as a model with potential to obtain and use MSC in preclinical studies. These animals are phylogenetically close to the domestic pig, popularly known as peccaries and found naturally in South America, Central America and the South of the United States. The aim of the present study was to establish a protocol for the isolation, in vitro cell expansion, differentiation and assessment of the stromal MSC growth curve before and after thawing. Materials, Methods & Results: Mesenchymal stem cells (MSC) from collared peccary bone marrow (Tayassu tajacu) were isolated and expanded by centrifuge in Ficoll® solution and cultured in DMEM® High Glucose medium. The culture was assessed by assays of colony forming units CFU-F and growth curve by saturation (GCS). Cultures in the third passage, with 70% confluence, were replicated at 105 cells/mL concentration in the culture media to induce osteogenic cell differentiation and adipogenic cell differentiation, respectively. The MSC were frozen in nitrogen for 40 days, thawed and re-assessed for cell viability and GCS. Discussion: The bone marrow collected presented high mononuclear cellularity, with a mean variability of 94.5% and 60.83 ± 4.27 UFC were identified in the samples and cells with fibroblast-like-cell morphology were observed. When they were expanded, the mean cell viability was 95%, the mean cell concentration obtained was 233.31 ± 20.04 cells per 25cm2 bottle and the culture reached the growth plateau in GCS between the 13th and 16th day. The osteoblastic cell differentiation assay showed after 18 days, morphology similar to osteoblasts, with irregular cytoplasm limits, cell prolongation formation and flattened appearance. [...]

Um novo modelo de isolamento do tumor de Walker utilizando o gradiente de Ficoll-Hypaque / A novel model for isolation of Walker's tumoral cells using the Ficoll-Hypaque gradient

OBJETIVO: Analisar uma nova técnica de isolamento das células do tumor de Walker, utilizando o gradiente de ficoll-hypaque. MÉTODOS: Vinte ratos Wistar machos foram divididos em 2 grupos (G1, G2). O tumor do animal doador foi dissecado, triturado em solução de ringer lactato e filtrado. A suspensão celular obtida foi dividida em duas alíquotas (A1 e A2) e a alíquota A2 foi centrifugada em gradiente de ficoll-hypaque. As duas alíquotas foram ajustadas para uma concentração de 1X10(6) células/ml. Um ml da suspensão A1 ou A2 foi injetado por via subcutânea na axila direita dos ratos dos seus respectivos grupos. Os diâmetros tumorais, peso tumoral e análise histológica foram avaliados. RESULTADOS: Não houve diferença no volume tumoral (G1=17,9±3,8cm³; G2=17,2±4,4cm³; p=0,190) e no peso tumoral (G1=7,0±1,8g; G2=7,3±2,8g; p=0,569). A análise histológica evidenciou padrões semelhantes de infiltração de células pequenas indiferenciadas e de necrose nos dois grupos. Entretanto, exsudato granulocítico leve a moderado foi mais acentuado no G2 do que no grupo G1 e hemorragia leve a moderada foi observada somente no grupo com ficoll. CONCLUSÃO: O gradiente de ficoll-hypaque é uma técnica adequada de isolamento das células do tumor de Walker e fornece uma suspensão celular menos contaminada com outros tipos celulares. (AU)

PURPOSE: The purpose was to evaluate a novel technique for isolation of Walker's tumoral cells using a Ficoll-Hypaque gradient and its further influence on tumor development.METHODS: Twenty male Wistar rats have been divided in 2 groups: G1= without ficoll, G2= with ficoll. Tumor was excised, homogenized and suspended in lactate ringer. A sample of the cell suspension was adjusted at a concentration of 1X106 cells/ml (G1). A second sample was centrifuged on a Ficoll-Hypaque gradient and the cell concentration was then adjusted (G2). Tumor was implanted by subcutaneous injection of 1.0 ml in the right armpit of rats. Tumor volume (TV) and tumor weight (TW) were compared in two groups.RESULTS: There were no differences between the two groups in TV (G1=17.9±3.8cm3 vs. G2=17.2±4.4cm3; p=0.190) and TW (G1=7.0±1.8g vs. G2=7.3±2.8g; p=0.569). The histological analysis showed similar patterns of infiltration by small-undifferentiated cells and necrosis in both groups. However, a mild to moderate granulocytic exsudate was more frequent in the animals whose tumors derived from Ficoll-isolated cells. Hemorrhage from slight to moderate was only observed in this group.CONCLUSION: A Ficoll-Hypaque gradient can provide more adequate isolation of Walker's tumor and the cell suspension obtained by this technique has lower contamination by other cell types.(AU)