Effects of hydrosalpinx on endometrial implantation failures: evaluating salpingectomy in women undergoing in vitro fertilization / Efeitos do hydrosalpinx no falho de implantação endometrial: Avaliar a salpingectomia nas mulheres em curso de fertilização in vitro

Abstract Hydrosalpinx is a disease characterized by the obstruction of the salpinx, with progressive accumulation in the shape of a fluid-filled sac at the distal part of the tuba uterina, and closed to the ovary. Women with hydrosalpinges have lower implantation and pregnancy rates due to a combination of mechanical and chemical factors thought to disrupt the endometrial environment. Evidence suggests that the presence of hydrosalpinx reduces the rate of pregnancy with assisted reproductive technology. The main aim of the present is review to make an overview of the possible effects of hydrosalpinx on in vitro fertilization (IVF).We conducted a literature search on the PubMed, Ovid MEDLINE, and Google Scholar data bases regarding hydrosalpinx and IVF outcomes. Hydrosalpinx probably has a direct toxic effect on sperm motility and on the embryos. In addition, the increasing liquid inside the salpinges could alter the mechanisms of endometrial receptivity. The window of endometrial receptivity is essential in the implantation of blastocysts, and it triggers multiple reactions arising from the endometrium as well as the blastocysts. Hydrosalpinx could influence the expression of homeobox A10 (HOXA10) gene, which plays an essential role in directing embryonic development and implantation. Salpingectomy restores the endometrial expression of HOXA10; therefore, it may be one mechanism by which tubal

Interacción endometrio trofoblasto, en la implantación humana: revisión de la literatura / Endometrium-trophoblast interaction in human implantation: review of literature

Un embarazo exitoso requiere de una serie de interacciones mediadas por factores hormonales, moleculares y fenómenos de inmunomodulación. Una de estas interacciones es la que ocurre entre el endometrio y el blastocito, previo y durante el proceso de implantación. El objetivo de esta revisión bibliográfica es complementar lo descrito en la literatura clásica de embriología humana sobre interacción de endometrio-blastocito. La búsqueda bibliográfica se realizó en la base de datos MEDLINE usando los términos en inglés "implantation", "endometrium" y "embryo"; además se realizó una búsqueda manual, que incluyó artículos de revistas no indexadas, libros de texto y atlas. Se consideraron criterios de inclusión y exclusión para la selección de los artículos y otros recursos bibliográficos. Entre los criterios de inclusión se consideraron estudios realizados en humanos, artículos de revisión y experimentación, publicados en los últimos 5 años. Como criterios de exclusión se consideraron artículos que utilizaran animales, estudios sobre fertilidad in vitro, patologías asociadas y artículos no relacionados al tema. Una vez completada la selección, se examinaron los textos completos, en los cuales se aplicaron nuevamente los criterios de exclusión. La búsqueda arrojó un total de 560 artículos, cuyo análisis de los títulos y resúmenes resultó en 475 trabajos excluidos, a partir de los diferentes criterios de exclusión antes descritos. Por lo tanto, se obtuvieron 85 artículos, en los cuales se realizó el análisis del texto completo. De estos artículos, se obtuvieron un total de 34 estudios y los contenidos seleccionados en esta revisión fueron: Endometrio, Interacción endometrio trofoblasto, Aposición, Adhesión y Migración-Invasión. Durante la implantación se genera una interacción entre el endometrio y el trofoblasto, con la participación de moléculas reguladoras de proliferación y diferenciación, como factores hormonales, moleculares y de expresión génica. Sin embargo, los mecanismos específicos de acción e interacción deben continuar siendo investigados, para responder interrogantes en el ámbito del crecimiento y desarrollo humano.

A successful pregnancy requires a series of interactions, mediated by hormonal, molecular and immunomodulation phenomena. One of these interactions is between the endometrium and the blastocyst, before and during the implantation process. The objective of this literature review is to complement what is described in the classic human embryology literature on endometrial-blastocyst interaction. The bibliographic search was carried out in the MEDLINE database using the terms "implantation", "endometrium" and "embryo", and a manual search was carried out, which included articles from non-indexed journals, textbooks and atlases. Inclusion and exclusion criteria were considered for the selection of articles and other bibliographic resources, including human studies, review and experimentation articles, published in the last 5 years. Articles with animals as experimental subjects, in vitro fertility studies, associated pathologies and articles not related to the subject were excluded. When the selection was completed, the complete texts were examined, in which the exclusion criteria were applied again The search yielded a total of 560 articles, whose analysis of titles and abstracts resulted in 475 excluded works, in relation to different exclusion criteria described above. Therefore, 85 articles were obtained, in which the complete text analysis was performed. From these articles, a total of 34 studies were obtained and the contents selected in this review were: Endometrium, Endometrium trophoblast, Aposition, Adhesion and Migration-Invasion. During the implantation, aninteraction between the endometrium and the trophoblast is generated, with the participation of regulatory molecules of proliferation and differentiation, such as hormonal, molecular and gene expression factors. However, the specific mechanisms of action and interaction must continue to be investigated, to answer questions in the field of human growth and development.

Bovine conceptus of Bos indicus produced by somatic cell nuclear transfer and parthenogenesis present morphological variations since the blastocyst stage / Conceptos bovinos (Bos indicus) produzidos por transferência nuclear de células somáticas e partenogênese apresentam variações morfológicas desde o estágio de blastocisto

In cattle, embryo development is characterized by the appearance of two distinct cell layers, the trophectoderm and the inner cell mass. The latter will undergo differentiation to form the embryonic disc consisting of the epiblast and hypoblast. The aim of this study was to ultrastructurally characterize the bovine embryo from different in vitro production techniques, with emphasis on trophectoderm and inner cell mass cells. Bovine embryos on day 7 (conception = D1) of pregnancy, derived via in vitro production techniques, were fixed for light and transmission electron microscopy processing. Results suggested that embryos produced by nuclear transfer of somatic cells and parthenogenesis showed significant changes in macroscopic and microscopic structure. Size was reduced, and the inner cell mass had no defined shape. Furthermore, organelles responsible for the absorption processes, communication, growth, and cellular metabolism were fewer and had changes in shape, when compared to results in embryos produced by in vitrofertilization. We concluded that embryos produced by parthenogenesis and SCNT exhibit morphological differences when compared with IVF embryos, such as undeveloped blastocoel, poorly defined distribution of ICM, and morphological differences in organelles.

Em bovinos, o desenvolvimento embrionário é caracterizado pelo surgimento de duas camadas distintas, o trofectoderma e a massa celular interna. Este último irá sofrer diferenciação para formar o disco embrionário, o qual consiste em epiblasto e hipoblasto. O objetivo deste estudo foi caracterizar ultraestruturalmente o embrião bovino proveniente de diferentes técnicas de produção in vitro, com ênfase no trofectoderma e na massa celular interna. Embriões bovinos com sete dias de gestação (fecundação = D1), derivados de técnicas de produção in vitro, foram fixados para processamento de microscopia de luz e eletrônica de transmissão. Os resultados sugerem que os embriões produzidos por transferência nuclear de células somáticas e partenogênese apresentaram alterações significativas em suas estruturas macro e microscópica. O tamanho foi reduzido, e a massa celular interna não tinha uma forma definida. Além disso, organelas responsáveis por processos de absorção, comunicação, crescimento e metabolismo celular estavam em menor número e tinham alterações na forma quando comparadas aos resultados em embriões produzidos por fertilização in vitro. Conclui-se que os embriões produzidos por SCNT e partenogênese apresentam diferenças morfológicas quando comparados aos embriões de fertilização in vitro, tais como blastocele pouco desenvolvida, massa celular interna pouco definida e diferenças morfológicas nas organelas.

Effects of melatonin and prolactin in reproduction: review of literature / Efeitos da melatonina e da prolactina na reprodução: revisão de literatura.

Summary The pineal gland is responsible for producing a hormone called melatonin (MEL), and is accepted as the gland that regulates reproduction in mammals. Prolactin (PRL) also exhibits reproductive activity in animals in response to photoperiod. It is known that the concentrations of PRL are high in the summer and reduced during winter, the opposite of what is seen with melatonin in these seasons. In placental mammals, both prolactin and melatonin affect implantation, which is considered a critical point of pregnancy, since a successful pregnancy requires the development of a synchronous interaction between the endometrium and blastocyst for placental development. It is also known that PRL levels during pregnancy are essential for the maintenance of pregnancy, because this hormone induces the corpus luteum to produce progesterone, in addition to stimulating blastocyst implantation to maintain pregnancy and form the placenta. However, melatonin levels in plasma have also been shown to increase during pregnancy, peaking at the end of this period, which suggests that this hormone plays an important role in the maintenance of pregnancy. Thus, it is clear that treatment with prolactin or melatonin interferes with the processes responsible for the development and maintenance of pregnancy.

Resumo A glândula pineal é responsável pela produção do hormônio melatonina (MEL), sendo aceita como a glândula reguladora da reprodução em mamíferos. A prolactina (PRL) também exibe atividade reprodutiva em animais, em resposta ao fotoperíodo. Sabe-se que as concentrações de PRL são elevadas durante o verão e baixam durante o inverno, ocorrendo o oposto com os níveis do hormônio melatonina nessas estações. Nos mamíferos placentários, tanto a melatonina quanto a prolactina influenciam a implantação, que é considerada o ponto crítico da gravidez, pois o sucesso da gestação requer o desenvolvimento de uma interação sincronizada entre o endométrio e o blastocisto para o desenvolvimento da placenta. Sabe- -se ainda que os níveis de PRL durante a gestação são essenciais para a manutenção da gravidez, pois esse hormônio induz o corpo lúteo a produzir progesterona, além de estimular a implantação do blastocisto, mantendo a prenhez e o desenvolvimento placentário. Em contrapartida, tem-se demonstrado também que os níveis de melatonina no plasma aumentam durante a gestação, atingindo valores elevados no fim desse período, sugerindo que esse hormônio desempenhe um importante papel na manutenção da gestação. Dessa forma, fica claro que o tratamento com prolactina ou melatonina interfere nos processos responsáveis pelo desenvolvimento e pela manutenção da gestação.

An ideal oocyte activation protocol and embryo culture conditions for somatic cell nuclear transfer using sheep oocytes.

Pluripotent stem cells are possibly the best candidates for regenerative medicine, and somatic cell nuclear transfer (SCNT) is one of the viable options to make patient-specific embryonic stem cells. Till date efficacy of SCNT embryos is very low and requires further improvement like ideal oocyte activation and in vitro culture system. The aim of the present study was to evaluate ideal oocyte activation using different stimulation protocols and to study the effect of cumulus co-culture conditions on embryo development. Results demonstrate that between electric stimulation and chemical stimulation using calcium ionomycin and ionophore, best oocyte activation was obtained using calcium ionomycin (5 μM for 5 min) which resulted in 83% cleavage followed by 7% of early blastocyst which further increased to 15% when a cumulus bed was also introduced during embryo culture. Sequential modified Charles Rosenkrans 2 (mCR2) medium was used for embryo culture in which glucose levels were increased from 1 mM to 5 mM from Day 3 onwards. SCNT using cumulus cells as donor somatic cell, calcium ionomycin to activate the reconstructed oocyte and embryo culture on a cumulus bed in sequential mCR2 medium, resulted in the development of 6% embryos to early blastocyst stage. Such technological advances will make SCNT a viable option to make patient-specific pluripotent stem cell lines in near future.

Culture medium composition affects the gene expression pattern and in vitro development potential of bovine somatic cell nuclear transfer (SCNT) embryos

Different culture systems have been studied that support development of somatic cell nuclear transfer (SCNT) embryos up to the blastocyst stage. However, the use of sequential and two-step culture systems has been less studied. The objective of the present study was to examine the developmental potential and quality of bovine SCNT embryos cultured in different two-step culture media based on KSOM, SOF and the macromolecules FBS and BSA (K-K/FBS, K-S/BSA and K-K/BSA, respectively). No differences were observed in the cleavage rate for any of the culture systems. However, there was a significant difference (P<0.01) in the rate of blastocyst development, with the K-K/ FBS culture system yielding a higher rate of blastocysts (28%) compared to other treatments (18 and 15%, for K-S/BSA and K-K/BSA, respectively). Although quality of embryos, as assessed by the total number of cells, was not different, the apoptosis index was significantly affected in the sequential culture system (K-S/BSA). Gene expression analysis showed alterations of DNMT1, IGF2, LIF, and PRDX6 genes in embryos cultured in K-S/FBS and of SOD2 in embryos cultured in K-K/BSA. In conclusion, we demonstrated that culture medium may affect not only the developmental potential of SCNT embryos but also, more importantly, the gene expression pattern and apoptotic index, presenting the possibility to manipulate the culture medium composition to modulate global gene expression and improve the overall efficiency of this technique.

Cloned calves derived from somatic cell nuclear transfer embryos cultured in chemically defined medium or modified synthetic oviduct fluid

Somatic cell nuclear transfer (SCNT) is considered to be a critical tool for propagating valuable animals. To determine the productivity calves resulting from embryos derived with different culture media, enucleated oocytes matured in vitro were reconstructed with fetal fibroblasts, fused, and activated. The cloned embryos were cultured in modified synthetic oviduct fluid (mSOF) or a chemically defined medium (CDM) and developmental competence was monitored. After 7 days of culturing, the blastocysts were transferred into the uterine horn of estrus-synchronized recipients. SCNT embryos that were cultured in mSOF or CDM developed to the blastocysts stages at similar rates (26.6% vs. 22.5%, respectively). A total of 67 preimplantational stage embryos were transferred into 34 recipients and six cloned calves were born by caesarean section, or assisted or natural delivery. Survival of transferred blastocysts to live cloned calves in the mSOF and the CDM was 18.5% (to recipients), 9.6% (to blastocysts) and 42.9% (to recipients), 20.0% (to blastocysts), respectively. DNA analysis showed that all cloned calves were genetically identical to the donor cells. These results demonstrate that SCNT embryos cultured in CDM showed higher viability as judged by survival of the calves that came to term compared to blastocysts derived from mSOF cultures.

Influência do diâmetro e da fase folicular sobre a competência in vitro de oócitos obtidos de novilhas da raça Nelore / Influence of diameter and follicular fase on the in vitro competence of oocytes from Nelore heifers

Avaliou-se o efeito do diâmetro e da fase do desenvolvimento folicular sobre a competência de oócitos para a produção in vitro de embriões bovinos. A primeira onda folicular foi sincronizada com progestógeno por nove dias e 24 horas após a sua retirada aplicou-se LH. Os ovários foram recuperados 60h (G-60), 96h (G-96) e 108h (G-108) após a ovulação induzida pelo LH. Os folículos foram dissecados ou aspirados e medidos e os oócitos recuperados e submetidos à maturação, fecundação e cultivo in vitro. Os ovários do G-60 apresentaram mais oócitos viáveis (graus I, II e III) (96,6 por cento). A taxa de clivagem teve efeito significativo sobre o diâmetro folicular, sendo maior nos oócitos oriundos de folículos classe 3 (>7mm). Na taxa de produção de blastocisto observou-se interação diâmetro versus fase de desenvolvimento folicular. A taxa de produção de blastocisto foi maior em oócitos obtidos de folículos com diâmetros <5mm (classe 1) no G-60 (64,5 por cento), de 5-7mm (classe 2) no G-96 (33,3 por cento) e >7mm (classe 3) no G-108 (50 por cento). Conclui-se que o diâmetro e a fase de desenvolvimento folicular influenciam a competência oocitária para o desenvolvimento in vitro. Nos estádios iniciais da onda folicular a produção de blastocisto foi maior em oócitos de folículos pequenos; com o avanço da onda, a produção de blastocistos foi maior em oócitos obtidos de folículos maiores.

The effect of follicular phase and follicle diameter on in vitro production of bovine embryos was evaluated. Follicular wave was synchronized in Nelore heifers with a progestogen for nine days and LH was administered 24 hours after progestogen withdrawal. Ovaries were recovered 60h (G-60), 96 h (G-96), or 108 h (G-108) after LH treatment. Ovarian follicles were dissected or aspirated and measured before oocytes were recovered and submitted to in vitro maturation, fertilization, and culture. The G-60 ovaries presented more viable oocyte (degrees I, II and III) (96.6 percent). Cleavage rate was higher for oocytes from follicles 7mm in diameter (class 3). There was a follicular phase-by-follicle diameter interaction effect on blastocyst production rate. Blastocyst production rates were higher for oocytes from follicles 5mm in diameter (class 1) in the G-60 group (64.5 percent), from follicles 5-7mm (class 2) in the G-96 group (33.3 percent), and from follicles 7mm (class 3) in the G-108 group (50 percent). Both the phase of follicular development and the follicle diameter influenced oocyte competence and ability for development in vitro. At the initial stages of the follicular wave, blastocyst production was higher for oocytes from small follicles. However, as the follicular wave advances, blastocyst production increases for oocytes from larger follicles.

Blastocyst-endometrium interaction: intertwining a cytokine network

The successful implantation of the blastocyst depends on adequate interactions between the embryo and the uterus. The development of the embryo begins with the fertilized ovum, a single totipotent cell which undergoes mitosis and gives rise to a multicellular structure named blastocyst. At the same time, increasing concentrations of ovarian steroid hormones initiate a complex signaling cascade that stimulates the differentiation of endometrial stromal cells to decidual cells, preparing the uterus to lodge the embryo. Studies in humans and in other mammals have shown that cytokines and growth factors are produced by the pre-implantation embryo and cells of the reproductive tract; however, the interactions between these factors that converge for successful implantation are not well understood. This review focuses on the actions of interleukin-1, leukemia inhibitory factor, epidermal growth factor, heparin-binding epidermal growth factor, and vascular endothelial growth factor, and on the network of their interactions leading to early embryo development, peri-implantatory endometrial changes, embryo implantation and trophoblast differentiation. We also propose therapeutical approaches based on current knowledge on cytokine interactions.

Development of bovine embryos reconstructed by nuclear transfer of transfected and non-transfected adult fibroblast cells

An association of two techniques, nuclear transfer (NT), and transfection of somatic animal cells, has numerous potential applications and considerable impact, mainly in agriculture, medicine, pharmacy, and fundamental biology. In addition, somatic cell nuclear transfer is the most efficient alternative to produce large transgenic animals. We compared in vitro and in vivo developmental capacities of NT using fibroblast cells isolated from a 14-month-old cloned Simmental heifer (FCE) vs the same line transfected with a plasmid containing neomycin-resistant genes (TFCE). There were no significant differences (P > 0.5) in either fusion (116/149 = 78% vs 216/301 = 72%), cleavage (78/116 = 67% vs 141/216 = 65%) and blastocyst (35/116 = 30% vs 52/216 = 24%) rates or in pregnancy rate at 30 to 35 days after embryo transfer (2/17 vs 3/17) between NT using FCE and TFCE, respectively. Transfection and long-term in vitro culture of transfected cells did not affect developmental capacity of NT embryos up to 40 days of gestation

Endocrine and paracrine correlates of endometrial receptivity to blastocyst implantation in the human.

Synchronous attainment of maternal endometrial receptivity allows implantation-stage adhesive blastocyst to undertake apposition, attachment and invasion. In the present essay, we propose a model according to which luteal phase progesterone induces a basic drive in endometrium toward receptivity and as a result, adequately primed endometrium differentiates through certain steps in a fixed action pattern. The implantation-stage embryo senses such endometrial responsiveness circumstantially by the factors secreted by maternal endometrium and undertakes differentiation to implant by secreting factors which act on maternal endometrial cells to further potentiate them to implantation stage-specific changes. Such a dynamic temporo-spatial manner of interaction involving a set of specific factors acting synchronously leads to the activation of innate releasing process in both compartments towards embryo attachment followed by successful intrusion and controlled invasion of trophoblast cells into maternal endometrium. In the present review we discuss the potential role of various endocrine and paracrine factors in the process of blastocyst implantation in the human.

Embryo-endometrial proteases during early mammalian development.

In mammals, extensive remodeling of uterine endometrial matrix occurs during reproductive cycle and blastocyst implantation. This is regulated by a variety of molecules such as hormones, growth factors, cytokines and proteases. In this article, we review the current state of knowledge available on various proteases and their inhibitors functionally involved in the embryo-endometrial tissues and present some data on endometrial proteases in hamsters and rats during estrous cycle and early pregnancy. We demonstrate the presence of at least four gelatinolytic activities in endometrial samples, belonging to gelatinase-A and -B categories and their dependence on calcium/zinc ions for enzyme activity and, their interrelationships between zymogen and active forms. We believe that the embryo-endometrial proteases are essential for hatching of blastocysts and for the dynamic remodeling of endometrial tissues, occurring during the critical peri-implantation period.

Experimental models for human implantation.

An understanding of the cellular and molecular basis of blastocyst implantation in the human remains as yet a black box, however, a few experimental models using human and non-human primate species have addressed this issue. This review attempts to highlight, based on experimental evidence, the paradigm shifts in our understanding of the endocrine basis of embryo implantation, and the nature of dialogue between a growing, viable conceptus and maternal endometrial cells in the establishment of 'receptivity' for blastocyst implantation. It is being proposed that an existing inflammation paradigm of blastocyst implantation could be tested using an experimental model to compare tissue behaviour of conceptus associated endometrial cells with that occurring after induction of deciduoma in hormone-primed uterus. We anticipate that an in vitro model of blastocyst implantation using the experimental models of homotypic and heterotypic cultures of uterine epithelial and stromal fibroblast cells expressing structural and functional phenotypic responses as observed in situ may provide us with necessary clues about the temporal and spatial nature of cellular and molecular functions involving various endocrine and paracrine factors at implantation.

Vero Cell Co-culture Counteracts the Detrimental Effects of Hydrosalpinx Fluid on the Development of Mouse Embryos in vitro

Recent studies have suggested that the hydrosalpinx has a negative effect on pregnancy outcome, with markedly diminished implantation and increased early pregnancy loss. Fluid from the hydrosalpinx may leak into and accumulate in the uterine cavity. It is not clear, however if this creates a hostile local environment in the uterus for embryo implantation or exerts a direct embryotoxic effect. This study was conducted to investigate the detrimental effects of hydrosalpinx fluid (HSF) on the development of mouse embryos in vitro and to demonstrate whether Vero cells overcome these adverse effects. HSF was collected from three women with bilateral hydrosalpinx at the time of laparoscopic surgery. Collected fluid was centrifuged and the supernatant was frozen at -20degrees C. For co-culture, Vero cells were commercially obtained in a frozen state and cultured using Ham's F10 medium. Single-cell mouse embryos (B6CBAF1) were cultured for 5 days in 0, 0.4, 0.8, and 1.2% of HSF in media with and without Vero cells and examined daily to record the number of embryos reaching expanded blastocyst and hatching stage. Co-culture of mouse embryos with Vero cells at 0.8% HSF concentration significantly enhanced embryo development, but not at 1.2% hydrosalpinx fluid concentration. These results suggest that HSF is highly embryotoxic and Vero cells are likely to overcome these detrimental effects to some degree.

Como um mamífero se desenvolve desde a fertilizaçäo até a implantaçäo do blastocisto / Physiological aspects of the mammalian from the fertilization until the implantation of the blastocyst

Monografia sobre o desenvolvimento embrionário de mamíferos durante a fase prévia a implantaçäo.

Reflexiones sobre los inicios del individuo humano / Reflections on the beginning of a new human individual

Although there is very little doubt that when a child is born a new actual person can be identified, there is continuous debate as to the moment in embryological development when that same person begins its ixistence. Based on today's knowledge of human fertilization and the early stages of embryo development, this position paper examines three theses that deal with the establishment of personhood. The first thesis stipulates that a human individual exists prior to syngamy. Although the sperm has penetrated the plasmatic membrane of the oocyte, the genetic information contained in both gametes remain separated in the male and female pronucleus; thus, the oocyte contains the sum of two identities responsible for creating a new individual. This paper will argue that a human individual has not yet formed. The second thesis recognizes that with syngamy, a unicellular structure (zygote) is established, endowed with genetic individuality and with the potential to become a person maintaining that same genetic framework throughout its lifetime. The third thesis argues that although genetic individuality is established with syngamy, the ontological individuality is only reached once genetic expression and cellular specialization are achieved and twinning is on longer possible (15 days after fertilization)

Los nuevos moduladores endometriales en el embarazo temprano / New endometrial modulators in early pregnancy

Se pensó por mucho tiempo que las citocinas sintetizadas por el útero y la placenta eran producidas exclusivamente por y para actuar sobre las células linfohematopoyéticas. Si bien muchas de estas citocinas modulan la fase efectora del sistema inmune, en el tracto reproductor femenino, sus principales células blanco y sitios de síntesis no son las células epiteliales uterinas, las células deciduales y el trofoblasto parecen ser la fuente principal de las citocinas. Esto sugiere dos alternativas no necesariamente exclusivas: o que estas células son extensiones que regulan al sistema inmune o que estos factores modulan el crecimiento y diferenciación de los tejidos uterinos y embrionarios. En el presente trabajo se analizan los sitios de síntesis, las células blanco y las posibles funciones de la citocinas durante la gestación temprana.

Influencia del nivel de progesterona plasmática sobre el porcentaje de preñez en hembras bovinas receptoras de embriones / Influence of plasma progesterone level on pregnancy rates in bovine embryo transfer recipients

Se obtuvieron muestras sanguíneas de 84 hembras bovinas receptoras de embriones el día de la transferencia y se determinó el nivel de progesterona para conocer si había diferencia entre el nivel promedio de progesterona de las receptoras que lograron una gestación y aquellas que no lo lograron. También se estudió la relación entre diversos niveles de progesterona y el porcentaje de preñez. La transferencia de los embriones se realizó 7 días después del estro por el método no quirúrgico. La sangre se recolectó inmediatamente después de la transferencia, se centrifugó y el plasma se congeló; la concentración de progesterona se determinó por radioinmunoanálisis. El diagnóstico de preñez se realizó por palpación transrectal 42 días después de la transferencia. El analisis estadístico reveló que el nivel promedio de progesterona plasmática de las receptoras que quedaron gestantes (3.005 ñ 0.96 ng/ml) no fue diferente significativamente (P > 0.05) del nivel promedio de las receptoras no gestantes (3.218 ñ 1.08 ng/ml). Tampoco se encontró diferencia entre el porcentaje de preñez de los 3 diferentes grupos de progesterona estudiados. Las receptoras con ó ng/ml de progesterona tuvieron 47.3 por ciento de preñez, las que tuvieron entre 2.5 y 4.9 ng/ml, un 60 por ciento y las que tuvieron 5 ng/ml, un 40 por ciento. En este estudio no se encontró evidencia de que la concentración de progesterona plasmática de la receptora al momento de la transferencia, sea una causa que influya sobre el porcentaje de preñez