47 research outputs found
Analysis of Permissive and Repressive Chromatin Markers in In Vitro Fertilized Bovine Embryos Just After Embryonic Genome Activation
Chromatin Modifying Agents in the In Vitro Production of Bovine Embryos
The low efficiency observed in cloning by nuclear transfer is related to an aberrant gene expression following errors in epigenetic reprogramming. Recent studies have focused on further understanding of the modifications that take place in the chromatin of embryos during the preimplantation period, through the use of chromatin modifying agents. The goal of these studies is to identify the factors involved in nuclear reprogramming and to adjust in vitro manipulations in order to better mimic in vivo conditions. Therefore, proper knowledge of epigenetic reprogramming is necessary to prevent possible epigenetic errors and to improve efficiency and the use of in vitro fertilization and cloning technologies in cattle and other species
Colpocitologia do ciclo estral em gatas
Foram submetidas à colpocitologia 10 gatas, sem raça definida, cedidas pelo Hospital Veterinário Governador Laudo Natel da FCAVJ-UNESP, as quais permaneceram em gatis individuais, recebendo ração balanceada e água à vontade. As fases do ciclo estral foram definidas pela identificação e contagem das células epiteliais descamativas da vagina. Neste trabalho, observou-se que o número de células superficiais anucleadas predominaram nas fases de proestro e estro, ao passo que as células superficias nucleadas foram identificadas em maior número no proestro. Já as células intermediárias e parabasais apresentaram-se em números mais expressivos no metaestro e anestro. Com relação às células parabasais, houve predominância destas na fase de anestro.Colpocytology was performed in ten female cats of unknown breed, granted by the Hospital Veterinário Governador Laudo Natel of FCAVJ-UNESP, which remained in individual cages, with balanced feeding and water “ad libitum”. Estrous cycle phases were defined by classification and by couting scaled of epithelial cells from vagina. In that trial, it was observed that the number of anuclear superficial cells prevailed during proestrus and oestrus, while nucleated superficial cells were found in greater number at proestrus. Parabasal and intermediate cells were present at metestrum and anestrus in more expressive numbers. Regarding parabasal cells, there was a prevailance at the anestrus stage
Resulting alterations at the level of testes and semen in dogs submitted to vincristine sulphate administra tion
Foram estudados 14 animais da espécie canina, sem raça definida, machos, adultos, com o objetivo de analisar, laboratorialmente, o sêmen e os aspectos histológicos dos testículos antes e após a administração do sulfato de vincristina. Para tanto, os animais foram divididos em 2 grupos. No grupo I (8 animais), submeteu-se os animais à orquiectomia unilateral e um fragmento do testículo e epidídimo foram analisados histologicamente. Ao término das aplicações, os animais sofreram a orquiectomia do testículo remanescente e foram avaliados histologicamente. No grupo II (6 animais), inicialmente, condicionou-se os animais para colheita de sêmen. Após obtenção do material fecundante, este foi analisado laboratorialmente. No grupo I, todos os animais apresentaram degeneração testicular em grau leve ou moderada. No grupo II, observaram-se alterações espermáticas, principalmente ao nível de peça intermediária e cauda. Entretanto, considerando que em termos de média, as características físicas e morfológicas do sêmen de cães sofreram alterações que são reversíveis à utilização do sulfato de vincristina, como recurso terapêutico, pode ser instituído nesta espécie animal.Sperm analysis and testicular histological studies were performed before and after vincristine sulphate treatment, in fourteen male dogs. In group I (n = 8), unilateral orchiectomy was carried out before and after mitostatic treatment, and testicular and epididymal biopsies were examined histologically. All histological examinations showed a slight to moderate degeneration of testicular tissue. In group II (n = 6) semen was collected and was submitted to laboratorial analysis. After vincristine treatment, middle piece and tail abnormalities were found. However, as physical and morphological abnormalities showed to be reversible, vincristine sulphate therapy may be used in such species
Effect of follicular fluid supplementation during in vitro maturation on total cell number in bovine blastocysts produced in vitro
Efeitos de diferentes sistemas de cultivo in vitro sobre o crescimento de folículos pré-antrais isolados de ovários de fetos bovinos
The objective of this study is to use different in vitro culture systems of preantral follicles from Nelore breed bovine fetuses in the last gestation quarter. The evaluation of treatments considered the time of growth of isolated follicles. Preantral follicles were mechanically isolated and submitted to the individual culture, for 9 days, in media no supplemented or supplemented with fetal calf serum (FCS), bovine serum albumin (BSA) or synthetic defined supplement substitute of serum KnockoutSR (KNO). We have also evaluated the effects of collagen gel or fetal calf fibroblast monolayer as substratum for in vitro cultures. The increase on the follicular diameter was followed in the first day (0 h), at the 72 h, 144 h and 216 h. Considering cultures of isolated follicles, the results have shown that the association between media supplemented with FCS and collagen gel was significantly more efficient on the increase of the follicular diameter than other treatments. It is not still established a system of appropriate cultivation that sustains the differentiation and multiplication of the granular cells and that maintains the contact of the same ones with the oocyte to provide molecules and factors that supply the metabolic demand. We also understand that our results also represent another promising step on the search for the ultimate system of in vitro culture of preantral follicles from bovines
Technical and biological aspects on recovery of oocytes from cattle donors: bibliographical review
Desde o primeiro relato de colheita de embriões, um grande número de trabalhos tem apresentado os esforços para melhorar a contribuição genética de fêmeas bovinas. O objetivo desta revisão consiste em relacionar os primeiros trabalhos, novas descobertas e inovações técnicas da obtenção de oócitos em vacas.Since the first work about embryo collection, a great amount of research and development has founded on enhancing genetic contribution of cows. The aim of this publication is to give an account of the current knowledge, new findings and techniques on recovery of oocytes from cattle donors
Fecundação in vitro de ovócitos bovinos com sêmen submetido a diferentes diluidores
O objetivo deste trabalho foi avaliar a influência do diluidor do sêmen no desenvolvimento in vitro de ovócitos bovinos após a maturação e fecundação in vitro. Ejaculado de um reprodutor foi fracionado e submetido a três diluidores: Lactose/gema de ovo (LG), Citrato/gema de ovo (CG) e Tris/gema de ovo (TG). Amostras deste material foram envasadas, congeladas e estocadas em N² e, posteriormente, descongeladas; a fração móvel foi separada por gradiente descontínuo de Percoll. A concentração espermática foi ajustada para 10 x 10(6)/mL e a capacitação espermática, induzida com 10 µg/mL de heparina. Após 24 horas de cultura para maturação in vitro, os ovócitos, aspirados de folículos ovarianos, foram inseminados com sêmen diluído em meio TALP e, após 48 horas de cultura, os zigotos foram transferidos para gotas de meio TCM 199, com 5% de soro fetal bovino, 5% de soro de vaca em estro e suspensão de células epiteliais do oviduto bovino, cobertas com óleo de silicone, e mantidos em cultura por nove dias. Todas as culturas foram realizadas a 38,5ºC em atmosfera com 5% de CO2. Os dados foram analisados pelo teste do qui-quadrado e houve diferença com relação à taxa de clivagem (TC), sendo as médias de 66,0; 69,3; e 54,4% para LG, CG e TG, respectivamente. Não houve diferença entre tratamentos com relação às taxas de mórulas/blastocistos ou de eclosão. O diluidor do sêmen não teve efeito sobre o desenvolvimento in vitro de embriões bovinos, embora a TC tenha sido afetada
Meiotic inhibition of bovine oocytes in medium supplemented with a serum replacer and hormones: effects on meiosis progression and developmental capacity
Aiming to improve the developmental competence of bovine oocytes during meiotic block, this study evaluated the effects of a serum replacer (Knockout SR(R)) and hormones (gonadotropins and estradiol) supplementation of prematuration medium (TCM119 with 0.5 mM IBMX [IBMX group] or 25 mu M roscovitine [ROSC group]) on the kinetics of oocyte nuclear maturation and embryo development. Most IBMX and ROSC oocytes prematured for 8 h culture remained in the GV stage (70.3% and 73.1%, respectively; p > 0.05) similar to Control 8 h (63.5%) and to control immature oocytes (Control 0 h, 92.5%). After prematuration for 16 h, no oocytes remained in the GV stage at similar rates to those recently aspirated (p 0.05) to IBMX (9.7%). After in vitro maturation (IMV) for 24 h, metaphase II (MII) rates for oocytes prematured during 8 h were similar (p > 0.05) between control and treatments (65.0-71.7%). Similarly, MII rates oocytes prematured during 16 h were similar (p > 0.05) between all groups (45.9-60.4%). Cleavage rates (67.8-78.2%), embryonic development in day-7 (25.0-35.6%) and hatching rates in day-8 (2.5-11.3%) oocytes blocked during 8 h were similar for all groups (p > 0.05). Results indicate that addition of Knockout SR(R) and hormones to meiotic block culture with IBMX and roscovitine negatively affected meiotic arrest, but did not impair oocyte nuclear maturation and acquisition of developmental competence.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES