Morte embrionária precoce em éguas: aspectos clínicos e hormonais

The present study aimed to diagnose early embryonic death in 128 mares. Blood samples were collected at the 4th, 7th, 10th, 13th, 16th, 19th, 21st and 30th day after ovulation and the diameter of the corpus luteum was measured. The diameter and characteristics of the embryonic vesicle were evaluated by ultrasonography. Microbiology, cytology and histopathology were carried out in mares with embryonic death. Plasma oestrogen and progesterone concentration were measured by radioimmunoassay. From 128 mares, 17 (13.28%) showed early embryonic death. The embryonic losses took place at 19 days of pregnancy in 47.05% and at 21 days of pregnancy in 29.4% of the mares. The diameter of the corpus luteum in the mares that maintained pregnancy was similar to those with embryonic loss. Otherwise, the diameter of the embryonic vesicles was bigger at the 16th, 19th, 21st and 30th day of pregnancy when compared to the mares with embryonic loss. The mean plasma progesterone concentration was similar in both groups and the median plasma oestrogen concentration was higher in the pregnant mares. The cytological, microbiological and histopathological exams revealed that most of the mares had endometritis. Ultrasonography provided an early diagnosis of pregnancy (from the 12th day post-ovulation) and important information about the development of embryo and embryonic death. Endometritis was considered the main cause of embryonic losses in this study.O presente estudo objetivou diagnosticar as causas da morte embrionária precoce em 128 éguas. Amostras de soro foram coletadas nos dias 4, 7, 10, 13, 16, 19, 21 e 30 após ovulação, para dosagens hormonais e mensurações do corpo lúteo. O diâmetro e as características da vesícula embrionária foram avaliados, através da ultra-sonografia, a partir do 12º dia pós-ovulação. Das 128 éguas estudadas, 17 (13.28%) apresentaram morte embrionária. O diâmetro do corpo lúteo, bem como as concentrações plasmáticas de progesterona, foi semelhante nos grupos que apresentaram morte embrionária e nos que mantiveram a gestação. Os níveis de estrogeno plasmático foram mais elevados no grupo das fêmeas que mantiveram a gestação. Os exames citológicos, microbiológicos e histopatológicos revelaram que a maioria das éguas com diagnóstico de morte embrionária eram portadoras de endometrites

Estudo da técnica de coleta, congelação e descongelação de embriões de caprinos (Capra hircus), da raça Saanen, portadores da translocação 5/15

This work studied the surgical technique for collecting embryos in the goat, using heterozygous donors for the 5/15 translocation, which were bred with translocated animals. At the same, time technical characteristics related to cryopreservation, thawing and cultivation of the structures were performed. Considering the superovulatory treatment, oestrus was observer 24 or 48 hours after removing the intravaginal sponge and 71 viable structures were yielded in 43 collections. The 1 -2 Propanediol proved to be an efficient cryoprotectant agent, and allowed the cultivation of all the embryos. This result was not observed when glycerol was used as a cryoprotectant agent. Adhesions due to multiple collections constitute a great challenge for the improvement of this technique, since they are considered a limiting factor to the use of donors in the beginning of their reproductive lives.No presente trabalho foi realizado um estudo da técnica cirúrgica de coleta de embriões na espécie caprina, utilizando-se doadoras heterozigotas para a translocação 5/15, acasaladas com animal translocado. Simultaneamente foram observados aspectos técnicos inerentes à criopreservação, descongelação e cultivo das estruturas recuperadas. Frente ao tratamento superovulatório, o cio foi observado em 24 ou 48 horas após a remoção da esponja intravaginal e foram recuperadas 71 estruturas viáveis em 43 coletas. O 1 -2 Propanodiol mostrou-se eficiente criopreservador, permitindo cultivo de todos os embriões, fato não observado quando utilizou-se o Glicerol. As aderências provocadas pelas repetidas coletas constituem-se no grande desafio no sentido de se aperfeiçoar a técnica, pois são consideradas um fator limitante ao uso de doadores no início da vida reprodutiva

Aspectos da dinâmica, seleção e maturação folicular em éguas pônei

O presente trabalho envolveu três experimentos: Influência da imunização passiva contra estradiol (E2) e a aspiração do maior folículo (F1) no momento do desvio folicular esperado, sobre a ocorrência do desvio folicular observado. Também foi objetivo verificar o efeito desses tratamentos sobre o perfil de hormônio folículo estimulante (FSH), hormônio luteinizante (LH) e inibina total circulante. Para tanto, os animais foram imunizados com dose única de soro anti-E2 (G anti-E2) ou o F1 foi aspirado no momento do desvio esperado (GAF1). O plasma sangüíneo foi obtido no período pré e póstratamento. O intervalo entre o dia da aplicação do soro (desvio esperado) e o dia da detecção do desvio foi em média o mesmo para o G anti-E2 e controle. No GAF1, a eliminação do maior folículo provocou atraso no momento da detecção do desvio folicular entre o segundo (F2) e o terceiro (F3) maior folículo, comparado ao controle. Em ambos os tratamentos o perfil de FSH, LH e inibina total foi similar ao controle. O experimento 2 tratou de um projeto piloto visando dominar a técnica de colheita de fluido dos grandes folículos ovarianos por meio de punção com agulha fina e o efeito desse procedimento sobre o folículo e às concentrações hormonais. Foram utilizados dois grupos de animais, G1 o folículo foi mantido intacto (controle) e G2 foi utilizada uma punção folicular quando o maior folículo atingiu diâmetro ~35 mm. Ultrasonografia ovariana foi realizada desde o ínicio da detecção de um folículo ~25mm, seguindo até a detecção da ovulação. O terceiro experimento objetivou verificar a influência de gonadotrofina coriônica humana (hCG) em folículos de 30 ou 35mm sobre as concentrações de hormônios esteróides e fatores intrafoliculares. A colheita do fluido folicular foi realizada imediatamente antes e 30 horas após a aplicação... (Resumo completo, clicar acesso eletrônico abaixo)The present study involved three experiments: The influence of passive immunization against estradiol (E2) and the largest follicle aspiration (F1) during the expected time of follicle deviation (F1~20mm) on observed follicle deviation occurrence. In addition, the study aimed to verify the related treatment effect on FSH, LH and total inhibin patterns in plasma. Therefore, the animais were immunized with a single dose of serum anti-E2 (G-anti E2) or the F1 was ablated at the expected time of deviation (GAF1). The blood samples were obtained at the pre and post treatment period. The interval between the day of anti-serum administration (expected time of deviation) and the day of deviation detection was similar for G-anti E2 and control groups. The GAF1 presented a delay on time detection of follicle deviation between the second (F2) and the third (F3) largest follicle upon elimination of the largest follicle when compared to control group. In both treatments, patterns of FSH, LH, and total inhibin were similar to control. The experiment 2 was a pilot project viewing training the technique to obtain follicular fluid from large ovarian follicles by puncture using a 25G needle, in addition to determine the effect of this procedure on follicle and hormonal concentrations. Two groups were used, G1 with the maintenance of intact follicle (control) and G2 with a follicle puncture when the largest follicle reached ~35mm in diameter. Ovarian ultrasonography was performed since the detection of a follicle 25mm and it remained until the detection of ovulation. The third experiment aimed to verify the influence of human chorionic gonadotrophin (hCG) on follicles measuring 30 or 35 mm, determining steroid hormone concentrations and intrafoJlicular factors. The follicular fluid collection was performed immediately before and 30 hours after hCG administration... (Complete abstract, click electronic access below

Expressão endometrial de receptores de estradiol e progesterona em éguas cíclicas, gestantes e acíclicas tratadas com hormônios esteroidais

The use of cyclic and non cyclic recipient mares in embryo transfer (ET) programs is a well established practice in equine reproduction. An advantageous alternative for horse owners and veterinarians is the use of non-cyclic recipients, since it makes possible the anticipation of the breeding season and reduces handling with the recipients. In order to establish pregnancy in the non-cyclic recipients, estrogens and progestins are administered to allow the induction of similar endometrial changes to those which occur in naturally pregnant mares. Administration of estradiol prior to progestins is based on cyclic mares’ researches, where estradiol produced during estrous stimulates the expression of estrogen and progesterone receptors in the endometrium. On the other hand, progesterone causes uterine changes that allow pregnancy establishment and maintenance. In addition, progesterone leads to reduction of estrogen and progesterone receptors during diestrous in cyclic mares. However, little is known about estrogen and progesterone endometrial receptors in non-cyclic mares, especially used in ET programs. The current study revises the gene expression pattern of estradiol and progesterone endometrial receptors in mares during estrous cycle, early pregnancy and submitted to estrogens and progestins hormonal treatments.A utilização de éguas receptoras cíclicas e acíclicas nos programas de transferência de embriões (TE) é uma prática consagrada na reprodução equina. Uma alternativa vantajosa para criadores e veterinários é o uso das receptoras acíclicas, uma vez que viabiliza a antecipação da estação de monta e reduz o manejo com as receptoras. Para se estabelecer a gestação nestas receptoras, estrógenos e progestinas são administrados, de forma a simular o ambiente hormonal uterino de éguas que se tornam naturalmente gestantes. A administração de estrógenos previamente às progestinas é baseada nos estudos em éguas cíclicas, que mostram que o estradiol, presente no período de estro, estimula a expressão dos seus próprios receptores e dos receptores para progesterona no endométrio. A progesterona, por sua vez, provoca mudanças uterinas que possibilitam o estabelecimento e manutenção da gestação e leva a redução dos receptores de estradiol e de seus próprios receptores durante o diestro e início da gestação. No entanto, pouco se sabe sobre os receptores endometriais de estradiol e progesterona em éguas acíclicas, principalmente utilizadas em programas de TE. O presente trabalho revisa o padrão de expressão gênica dos receptores endometriais de estradiol e progesterona em éguas durante o ciclo estral, início da gestação e submetidas a tratamentos hormonais com estrógenos e progestinas exógenas

Uterine and luteal hemodynamic evaluation of the non pregnant mare

Background: Studies with Doppler ultrassonography started at the end of the 90s for the determination of physiological and pathological alterations in the reproductive tract of the mare. Uterine alterations caused by inflammation, response from seminal plasma infusion, hormonal variations during estrous and diestrus, pregnancy and action of various vasoactive factors influence on the vascular perfusion detected by Doppler ultrasound. The development of efficient methods for uterine quality evaluation is of big importance for field equine reproduction veterinarians, once uterine environment is responsible for pregnancy maintenance. Review: Nowadays, the most used methods of uterine evaluation are the mode B ultrassonography, cytology, culture and biopsy. Hemodynamic evaluation of the uterus can be done by spectral data collected from large vessels, as A. uterine and its ramifications, or from subjective or objective evaluations from endometrium, miometrium and mesometrium attachment, which provide data referent to local and specific alterations of the evaluated area. Alterations in uterine vascular perfusion has been detected during estrous cycle, during pregnancy and in cases of infusion of inflammatory substances. These alterations happen because of vasoactive substances that act in the uterus during these events, however, most of these vasoactive substances are probably not even known. Also, important hemodynamic alterations in old mares, as an increase in vascular resistance, have been described. This increase might result from fibrosis of the uterus and in women it is considered to be a cause of infertility. In mares, periglandular fibrosis of the endometrium is considered to be the major diagnosable cause of embryonic and fetal loss in older mares. For the CL, ovarian artery of the mare supplies the ovary as well as the oviduct and therefore can be used for evaluation of these areas. The CL evaluation can also be done by the percentage of luteum area with colored signals as an indicator of the extent of blood flow. The percentage of the CL area with colored signals is determined subjectively by images observations in real time and/or by a freezing Power Doppler cross-section image with the maximum number of color pixels taped and the total number of color pixels is assessed by a computer analysis system. Therefore, a high correlation between plasmatic progesterone and CL vascularization also allows the CL evalution by this technique. In a first report, CL circulation reached its maximum on D5, the progesterone concentration in peripheral blood increased until D7 and in a posterior report, maximum perfusion was achieved two days after the maximum progesterone concentration (D8). Blood flow reduced between D10-D14 some days before the plasma progesterone decrease and, during the luteolytic period (D15-D17), the decline in CL blood-flow area was greater than blood flow decrease. Conclusion: Doppler ultrassonography add knowledge about uterine viability and CL functionality can be easily used by veterinarians in the field. It is a noninvasive method that provides real time results. However, because of the short time studies in this area have been done, many other answers still need to be found until normal and pathological patterns will be established

Uterine vascular perfusion and spectral-doppler measurements during early gestation in mares: new concepts of evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Doppler ultrasonography principles and methods of evaluation of the reproductive tract in mares

Background: Doppler ultrasonography is a non-invasive real time pulse-wave technique recently used for the transrectal study of the reproductive system hemodynamics in large animals. This technic is based in the Doppler Effect Principle that proposes the change in frequency of a wave for an observer (red blood cells) moving relative to the source of the respective wave (ultrasonic transducer). This method had showed to be effective and useful for the evaluation of the in vivo equine reproductive tract increasing the diagnostic, monitoring, and predictive capabilities of theriogenology in mares. However, an accurate and truthful ultrasonic exam requires the previous knowledge of the Doppler ultrasonography principles. Review: In recent years, the capabilities of ultrasound flow imaging have increased enormously. The current Doppler ultrasound machines offer three methods of evaluation that may be used simultaneously (triplex mode). In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the tissue that can be viewed as a two-dimensional gray-scale image on screen. This mode is primarily used to identify anatomically a structure for its posterior evaluation using colored ultrasound modes (Color or Spectral modes). Colored ultrasound images of flow, whether Color or Spectral modes, are essentially obtained from measurements of moving red cells. In Color mode, velocity information is presented as a color coded overlay on top of a B-mode image, while Pulsed Wave Doppler provides a measure of the changing velocity throughout the cardiac cycle and the distribution of velocities in the sample volume represented by a spectral graphic. Color images conception varies according to the Doppler Frequency that is the difference between the frequency of received echoes by moving blood red cells and wave frequency transmitted by the transducer. To produce an adequate spectral graphic it is important determine the position and size of the simple gate. Furthermore, blood flow velocity measurement is influence by the intersection angle between ultrasonic pulses and the direction of moving blood-red cells (Doppler angle). Objectively colored ultrasound exam may be done on large arteries of the reproductive tract, as uterine and ovary arteries, or directly on the target tissue (follicle, for example). Mesovarium and mesometrium attachment arteries also can be used for spectral evaluation of the equine reproductive system. Subjectively analysis of the ovarian and uterine vascular perfusion must be done directly on the corpus luteum, follicular wall and uterus (endometrium and myometrium associated), respectively. Power-flow imaging has greater sensitivity to weak blood flow and independent of the Doppler angle, improving the evaluation of vessels with small diameters and slow blood flow. Conclusion: Doppler ultrasonography principles, methods of evaluation and reproductive system anatomy have been described. This knowledge is essential for the competent equipment acquisition and precise collection and analysis of colored ultrasound images. Otherwise, the reporting of inconsistent and not reproducible findings may result in the discredit of Doppler technology ahead of the scientific veterinary community

Ovarian activity and plasma concentrations of progesterone and estradiol during pregnancy in jennies

The objectives of this study were to determine ovarian activity (with ultrasound) and plasma concentrations of progesterone and estradiol during pregnancy in jennies. There was considerable ovarian activity during the second month of pregnancy. Secondary corpora lutea (total of 2 to 7 per jenny) were formed (mainly by luteinization) starting on Day 41.8 +/- 1.0 (range Days 38 to 46; ovulation = Day 0). The echogenicity of the primary and secondary corpora lutea gradually decreased during pregnancy. Plasma progesterone concentrations increased between Days 0 and 10 (0.9 and 19.9 ng/mL, respectively), gradually decreased to Day 30 (12.1 ng/mL), increased between Days 30 and 40 (plateau, at approximately 17 ng/mL), gradually declined from Days 110 to 160 (nadir of approximately 6 ng/mL), and remained nearly constant until increasing again just before parturition. Plasma estradiol concentrations increased gradually from Day 65, peaked (1.2 ng/mL) on Day 165 (greater than or equal to 1 ng/mL on Days 150 to 210), and decreased thereafter, with very low concentrations during the last 20 d before parturition. Ovarian function and hormone profiles were generally similar to those previously reported during pregnancy in mares. (C) 1998 by Elsevier B.V