Mating with seminal vesicle-excised male can affect the uterus phospholipid fatty-acids composition during implantation in an experimental mouse model

ABSTRACT Purpose No comprehensive information is available about uterus fatty acid (FA) change during implantation period and possible effects of the seminal vesicle secretion on it. Materials and Methods In this study, we evaluated FA composition of uterus phospholipids during the implantation period in intact and seminal vesicle-excised (SVX) mated female mice. Forty NMRI female mice were divided into control (mated with intact male) and seminal vesicle excised (SVX)-mated (mated with SVX-male) groups. The phospholipid fatty acids composition was monitored during the first five days of pregnancy using gas chromatography and also implantation rate was evaluated on fifth day of pregnancy. Results We found that levels of linoleic acid (LNA) and arachidonic acid (ARA) showed a decreasing trend from the first to the third day of pregnancy and then started to increase on the fourth day and peaked on the fifth day. In contrast, the level of saturated FA (SFA) increased on the second and third day of pregnancy compared to the first (p<0.05) and then decreased on the fourth and fifth. We also found that the seminal vesicle secretion could affect the levels of LNA, ARA, SFA, and PUFA in uterine phospholipids especially on second and third day. Moreover, there was a positive correlation between ARA level and implantation rate in control but not SVX-mated groups. Conclusions It can be concluded that several uterus FA that have important roles in early pregnancy could be affected by seminal vesicle secretion.

Selección de sitios de anidación de Lepidochelys olivacea (Testudines: Cheloniidae) en el Pacífico Sur de Costa Rica / Nest-site selection of Lepidochelys olivacea (Testudines: Cheloniidae) in the South Pacific region of Costa Rica

Resumen La selección del sitio de anidación en tortugas marinas es determinante para la sobrevivencia de la progenie, sin embargo para Lepidochelys olivacea existe poca información al respecto. Este trabajo se enfocó en determinar si L. olivacea selecciona sus sitios de anidación de acuerdo a un patrón o preferencia espacial determinada, o si por el contrario distribuye sus nidos aleatoriamente en la playa. La recolección de datos se realizó entre julio y setiembre del 2011, en las playas de Piro y Pejeperro, Península de Osa, Costa Rica. La ubicación del nido se evaluó midiendo las distancias entre la línea de marea y el nido, entre el nido y la vegetación, y determinando la posición del nido con respecto a los sectores marcados cada 100m en la playa. En ambas playas, las tortugas mostraron una marcada preferencia por anidar lo más lejos posible de la línea de marea, lo cual protege a sus nidos de inundación pero los expone a un mayor riesgo de depredación. Además, en playa Piro se detectó una mayor concentración de nidos cerca de la desembocadura del río, y en las cercanías de un estero en el caso de Pejeperro. Si estas zonas están asociadas a un mayor éxito de eclosión, es posible que las tortugas estén regresando y seleccionado esos sitios por impronta o filopatría. Futuras investigaciones deberán enfocarse en determinar si en eventos de anidación sucesivos, L. olivacea muestra repetibilidad y mantiene sus preferencias de anidación a nivel de individuo.

Abstract In sea turtles, nest-site selection plays a key role in the survival of the offspring, with a direct influence on the sex of the hatchlings, incubation period, embryonic mortality, and hatchling size. Nest-site choice has been studied for most sea turtle species, but the information for Lepidochelys olivacea, the most abundant sea turtle species, is scarce. The present work explores the spatial nesting patterns of L. olivacea and seeks to determine whether this species employs a scatter nesting strategy or chooses to clump its nests based on a specific spatial preference. Night patrols were conducted between July and September 2011 at the beaches of Piro and Pejeperro, located in the Osa Peninsula, in the South Pacific region of Costa Rica. Nest-site location was evaluated by measuring the distance from the tide line to the nest, distance from nest to vegetation, and by noting beach sector according to beach-marker setup. In total, 84 nesting turtles were observed. Sea turtles in both beaches showed a strong preference to locate their nests as far from the tide line as possible, crawling longer distances when presented with wider stretches of beach. Turtles nesting at Piro beach also favored areas that were close to the river mouth, while turtles at Pejeperro preferred to nest near an estuary. It seems that the main driving force that influences L. olivacea to choose a nest site is to protect the eggs from tidal inundation, even if this means a higher predation risk from nesting too close to the vegetation, in addition to a longer trip to the ocean for both the female adult and the hatchlings. Nests near rivers and estuaries may have higher hatching success, which could prompt females to return and select these areas due to imprinting or philopatry. Future research focused on recapture could provide valuable information on individual behavior, and prove whether or not L. olivacea shows strong nest-site fidelity and repeatability of nesting preferences at the individual level. Rev. Biol. Trop. 63 (Suppl. 1): 375-381. Epub 2015 April 01.

Biópsia embrionária: qual a melhor escolha? / Embryo biopsy: what is the best choice?

Introdução: a biópsia embrionária tem como objetivo selecionar embriões geneticamente normais. Essa seleção ocorre por meio de testes genéticos pré-implantacionais. Espera-se, com isso, uma diminuição dos riscos de doenças genéticas e um aumento das taxas de implantação em fertilização in vitro. Objetivo: verificar, por meio de revisão bibliográfica, qual técnica de biópsia embrionária é considerada mais apropriada para feitura de testes genéticos pré-implantacionais. Método: pesquisa bibliográfica, na forma de revisão de publicações científicas, por meio das redes US National Library of Medicine (Pubmed), Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs), Google Acadêmico e Biblioteca Virtual em Saúde (BVS). Resultados e conclusão: existem três maneiras de efetuar a biópsia para reprodução humana assistida. A primeira consiste em retirar o primeiro e/ou o segundo corpúsculo polar estruído pelo oócito. Também se pode fazer a biópsia a partir de um blastômero do embrião em estágio de clivagem ou usar cinco a dez células do trofoectoderma de blastocisto. Normalmente as técnicas usadas para o diagnóstico são PCR, Fish, CGH array e SNP array, entre outras. Acredita-se que a biópsia de blastocistos é a melhor técnica para manter o potencial de implantação embrionária. Essa tendência se justifica por causa da maior quantidade de material genético disponível em fase avançada de desenvolvimento embrionário. Admite-se que nessa fase a incidência de mosaicismo seja menor em relação à biópsia de blastômeros, com consequente aumento na eficácia dos testes genéticos. Outra questão importante é que na biópsia de blastocistos as células são retiradas do trofoectoderma, enquanto que na biópsia em estágio de clivagem a remoção de um blastômero pode prejudicar o desenvolvimento embrionário.

Introduction: the embryo biopsy aims to select genetically normal embryos. This selection occurs through pre- implantation genetic testing. It is expected the reduction of risk ofgenetic disorders and increase implantation rates in IVF.Objective: to verify, through bibliographical revision, which embryo biopsy technique is considered more suitable for pre-implantation genetic diagnosis. Method: bibliographical research, in the form of literary review of scientific publications via networks, US National Library of Medicine (Pubmed), Latin-American Literature and Caribbean Health Sciences (Lilacs), Google Scholar and Virtual Health Library. Results and conclusion: there are three ways to perform the biopsy on assisted human reproduction.The first one consists in removing the 1st and/or 2nd polar body (if there wasfertilization). You can also perform the biopsy from the one blastomere of embryo cleavage stage or use 5-10 trophoectoderm cells blastocyst. Usually the techniques used for diagnosticpurpose are PCR, Fish, CGH array, SNP array and others. Nowadays it is believed that blastocyst biopsy is the best technique in order to maintain the embryonic implantation. This tendency is justified by the larger amount of genetic material available in an advancedstage of embryonic development. It is assumed that in this stage the incidence of mosaicism is reduced with the consequent increase in the effectiveness of genetic testing. Another important question is that the blastocyst biopsy cells are removed from the trophoectoderm while inbiopsy incleavage stage, the removal of one blastomere can impair embryonicdevelopment.

Endométrio na janela de implantação em mulheres com síndrome dos ovários policísticos / Endometrium in women with polycystic ovary syndrome during the window of implantation

O endométrio humano é submetido a uma complexa série de mudanças proliferativas e secretórias em cada ciclo menstrual e exibe somente pequeno período de receptividade, conhecido como "janela de implantação", necessário para a nidação do blastocisto no útero. O processo da implantação ocorre de forma sequencial, levando ao estabelecimento da gravidez. Alterações morfofuncionais durante este período podem impedir ou dificultar a implantação. Por este motivo, o estudo do endométrio nesta fase é importante para o aprimoramento de terapias que possam interferir nos mecanismos envolvidos na interção materno-embrionária. Várias doenças ginecológicas, incluindo a síndrome dos ovários policísticos (SOP), estão associadas à diminuição da fecundidade e da receptividade uterinas. Apesar de recentes avanços nas técnicas de reprodução assistida, permitindo a seleção de embriões de alta qualidade, a taxa de implantação continua baixa e não tem aumentado suficientemente nas últimas décadas. O presente artigo tem como objetivo revisar os aspectos endometriais da "janela de implantação" em mulheres com a síndrome dos ovários policísticos, focando especialmente as moléculas de adesão. Para tanto, nos valemos da análise de 105 artigos publicados em revistas indexadas no PUBMED nos últimos 50 anos (até maio de 2011). Como conclusão, a receptividade endometrial parece ser o maior fator limitante no estabelecimento da gestação em grande número de doenças ginecológicas, incluindo a SOP, e o tratamento para melhorar as taxas de implantação possivelmente será nessa direção.

The human endometrium undergoes to a complex series of prolifertive and secretory changes in each menstrual cycle and displays only a short period of receptivity, known as the "window of implantation", necessary for the implantation of the blastocyst in the uterus. The implantation process occurs in a sequential manner, leading to the establishment of pregnancy. Morphofunctional changes during this period may prevent or hinder the implantation. For this reason, the study of the endometrium at this stage is important for the improvement of therapies that may interfere with the mechanisms involved in maternal-embryonic interaction. Several gynecological disorders, including polycystic ovary syndrome (PCOS), are associated with decreased fertility and uterine receptivity. In spite of recent advances in assisted reproduction techniques, allowing the selection of high quality embryos, the implantation rate remains low and has not increased enough in recent decades. This article aims at reviewing the endometrial aspects of the "window of implantation" in women with polycystic ovary syndrome, focusing mainly on adhesion molecules. For that purpose, we analyzed 105 articles published in journals indexed in PubMed in the last 50 years (up to May 2011). In conclusion, the endometrial receptivity seems to be the major limiting factor for the establishment of pregnancy in a large number of gynecological diseases, including PCOS, and treatment to improve implantation rates is likely to be taken towards this direction.

Histochemical study of early embryo implantation in rats / Estudio histoquímico de la implantación temprana en ratas

Embryo implantation is the process that results in attachment of the conceptus to the uterine wall. In this histochemical study, we investigated the early stage of embryo implantation in rats by morphological analysis and by the detection of total proteins and glycosaminoglycans using hematoxylin-eosin, toluidine blue at pH 4.0 (TB), and Xylidine Ponceau at pH 2.5 (XP). In non-pregnant females, the uterine layers could be clearly distinguished and showed the normal histology of the organ. In pregnant females, an increase in the number of cells and a reduction in the interstitial space were observed in the endometrium close to the implantation sites. The blastocyst was partially inserted in the endometrium, with the observation of the inner cells mass around the blastocyst cavity surrounded by trophoblastic cells. TB staining revealed mild metachromatic basophilia, which was more evident in the endometrial stroma around the implantation site. Histochemical staining with XP was also more intense in the stroma close to the site of implantation. On the other hand, histochemical staining with either TB or XP was more discrete at sites distant from the conceptus. This study demonstrated changes in the endometrial stroma in areas adjacent to the site of embryo implantation, with variations in glycosaminoglycans and proteins as demonstrated by the detection of anionic and cationic radicals, respectively.

La implantación embrionaria es el proceso que resulta en la unión del embrión a la pared uterina. En este estudio histoquímico, se determinó la fase inicial de implantación del embrión en ratas mediante el análisis morfológico y por la detección de proteínas totales y glicosaminoglicanos con hematoxilina-eosina, azul de toluidina a pH 4,0 (TB) y xilidina Ponceau a un pH de 2,5 (XP). En las hembras no preñadadas, las capas del útero pueden ser claramente distinguidas y mostraron la histología normal del órgano. En las hembras preñadas, se observa un incremento en el número de células y una reducción en el espacio intersticial del endometrio para cerrar los sitios de implantación. El blastocisto se implanta parcialmente en el endometrio, con presencia de masa de células internas en torno a la cavidad del blastocisto, rodeado por las células trofoblásticas. La tinción TB reveló leve basofilia metacromática, lo cual fue más evidente en el estroma endometrial alrededor del sitio de implantación. Tinción histoquímica con XP también fue más intensa próximo del estroma en el sitio de implantación. Por otro lado, la tinción histoquímica, ya sea con la tuberculosis o XP fue más leve en los lugares distantes del embrión. Este estudio demostró cambios en el estroma del endometrio en las zonas adyacentes al sitio de la implantación del embrión, con variaciones en glucosaminoglicanos y proteínas, como lo demuestra la detección de radicales aniónicos y catiónicos, respectivamente.

Assisted hatching em reprodução assistida: uma meta-análise de ensaios clínicos controlados / Assisted hatching in assisted reproduction: a meta-analysis of clinical controlled trials

O objetivo desta meta-análise foi avaliar o efeito da assisted hatching (AH) sobre os resultados dos ciclos de reprodução assistida: gravidez clínica, nascimento vivo, gestação múltipla, aborto e implantação embrionária, sendo avaliados os artigos publicados em periódicos indexados ao PubMed por dois autores independentes. Foram levantados 51 ensaios clínicos controlados que avaliaram o efeito da AH, sendo 40 excluídos, resultando em 11 artigos completamente avaliados. Não houve diferença significativa na taxa de gestação clínica (44,41 versus 41,30%; p=0,19, AH versus controle, respectivamente) e na taxa de nascimento vivo (36,33 versus 34,79%, p=0,63), porém, foi identificada uma tendência de aumento na taxa de gestação múltipla (18,44 versus 15,02%, p=0,05). Também não foi identificada diferença significativa na taxa de aborto (6,66 versus 6,21%, p=0,83), mas observou-se um aumento significativo na taxa de implantação embrionária (24,32 versus 21,23%, p=0,02). A partir desses resultados, pode-se concluir que, até o momento, não existe evidência suficiente para suportar o uso da AH de rotina para ciclos de reprodução assistida com transferência de embriões frescos, uma vez que não houve aumento na taxa de gravidez clínica e/ou na taxa de nascimento vivo.

The aim of this meta-analysis was to evaluate the effect of assisted hatching on the outcome of assisted reproduction cycles: clinical pregnancy, live birth, multiple pregnancy, abortion and embryonic implantation, by assessing articles published in journals indexed in PubMed by two independent authors. Fifty-one controlled trials that evaluated the effect of assisted hatching were analyzed, and 40 of them were excluded, resulting in 11 articles fully assessed. There was no significant difference in clinical pregnancy rate (44.41 versus 41.30%, p=0.19, assisted hatching versus control, respectively), and in the live birth rate (36.33 versus 34.79%, p=0.63), but we identified a trend toward increased rate of multiple pregnancies (18.44 versus 15.02%, p=0.05). We also did not identify any significant difference in the rate of abortion (6.66 versus 6.21%, p=0.83), but a significant increase in the rate of embryo implantation was observed (24.32 versus 21.23%, p=0.02). From these results, we have concluded that, until now, there is not sufficient evidence to support the use of assisted hatching for routine assisted reproduction cycles with fresh embryo transfer, since there has not been an increase in clinical pregnancy rate and/or the rate of live birth.

Interleukin-1 beta regulates metalloproteinase activity and leptin secretion in a cytotrophoblast model

Implantation is one of the most regulated processes in human reproduction, by endocrine and immunological systems. Cytokines are involved in embryo-maternal communication and an impaired balance could result in pregnancy loss. Here we investigated the effect of interleukin 1-beta on the activity of two important metalloproteinases (MMP-2 and MMP-9) that are involved in extracellular matrix remodeling as well as the secretion of leptin, one of the reproductive hormones actively regulating their activity and secretion. We found that IL-1 beta activates matrix metalloproteinase activity as well as increases leptin secretion. We propose that this interleukin, through the regulation of leptin, in turn activates matrix metalloproteinases which results in an increased cytotrophoblast invasion.

Characterization of Calreticulin Expression in Mouse Endometrium during Embryo Implantation

Calreticulin (CRT), a Ca2+-binding storage protein and chaperone in the endoplasmic reticulum, modulates cell adhesiveness and integrin-dependent Ca2+ signaling. However, the role of CRT during implantation remains poorly understood. In the present study, we characterized the expression of CRT mRNA and the protein in mouse endometria from pregnancy DI to D7. Real-Time PCR and in situ hybridization results showed that the levels of CRT mRNA in the endometria of pregnant mice were significantly higher than those of non-pregnant mice (P<0.05), and increased gradually from pregnancy DI to D4, reaching the máximum level on D4, followed by a plateau from D4 to D7. Using immunofluorescence histochemistry and western blot, changes of CRT expression in the endometria of pregnant mice were consistent with the expression of CRT mRNA. Furthermore, antisense CRT oligodeoxynucleotide was injected into the uterus horns of pregnant mice (D3) to investígate its effect on embryo implantation. The result showed that the number of implanted embryos markedly decreased in the side of uterine horns receiving antisense CRT oligodeoxynucleotide(í><0.05). These findings suggest that CRT may play an important role in embryo implantation in mice.

Evaluación morfométrica de la relación embrio-uterina de las etapas pre y post implantacional en conejo (Oryctolagus cuniculus) / Morphometric evaluation of the embryo-uterine relationship of the pre and post implantational stages in rabbit (Oryctolagus cuniculus)

El conejo ha demostrado ser un excelente modelo de estudio de implantación. Como ovulador obligado, el tiempo de preñez se puede establecer en forma precisa. La observación morfológica de cortes de úteros de 7, 8, 9 y 10 días pos coito, permitió en este estudio reconstruir una secuencia de los eventos morfométricos que ocurren durante la implantación, en el conejo. Se utilizaron 20 conejas neozelandesas blancas adultas (Oryctolagus cuniculus), nulíparas, no gestantes. Para la cruza, se utilizaron 5 machos de probada fertilidad. Los conejos fueron obtenidos del Bioterio de la Facultad de Medicina de la Universidad de La Frontera, Temuco, Chile. Determinamos como día 0, el momento del coito, sacrificando las hembras los días 7, 8, 9 y 10 de cada cruza. Una vez sacrificados, se disecó macro y mesoscópicamente la región pélvica, seleccionándose vesículas uterinas para sus estudios histológico e inmunocitoquímico. Se realizaron estudios morfométricos y de cinética celular con las técnicas de Túnel y PCNA. Se efectuó estadística descriptiva en base a promedio y desviación estándar (p< 0.001), utilizando el programa estadístico Stata 9.0. Las mediciones morfométricas obtenidas fueron de diámetro y volumen de la vesícula uterina, altura de la pared uterina y lumen glandular de regiones mesometrial y antimesometrial, para los días 7 al 10 post coito. Los análisis inmunocitoquímicos permitieron determinar: índice apoptótico de los núcleos celulares y el índice celular mitótico. Para el día 8 post coito se observaron los cambios morfométricos más significativos a nivel del lumen vesicular, altura de pared uterina de la región mesometrial, y lumen glandular. El mismo día se observaron cambios importantes en los índices celular mitótico y apoptótico. El conejo podría ser una especie usada para predecir el normal desarrollo embrionario, tras la comprensión morfológica y morfométrica de la implantación. Presenta una forma poco invasiva de implantación...

The rabbit has demonstrated to be an outstanding implanting model. As an obligated ovulating animal, its pregnancy time can be established exactly. The morphologic observation of uterus cuts of 7, 8, 9 and 10 days post mating, allowed this research to rebutid an apparent sequence morphometric events, that take place during rabbit implantation. Twenty New Zealand, white, adult, female rabbits were used in this research. (Oryctolagus cunículus), nulipara. And 4, proven, fertile, males were used for mating. These males were obtained from the Bioterio of the Faculty of Medicine at the Universidad de La Frontera, Temuco, Chile. Mating day was defined as day cero, sacrificing the females days 7, 8, 9 and 10 in each mating. Once sacrificed, the pelvic region was macro and mesoscopically dissected, and the vesicles were selected for histological and immunocitochemical study. Histological studies were performed with H.E. technique; morphometric and cellular kinetics with Tunnel and PCNA techniques. Descriptive statistics was used based on an average and standard deviation (p< 0.001). The Stata 9.0 statistical program was used. The morphometric measurements obtained were: diameters and volume of the uterine vesicle, height of the uterine wall and glandular lumen of the mesometrial and antimesometrial regions to 7-10 days post coitus. The immunocitochemical analysis identified: apoptotic Index of the cellular nucleous and cellular mitotic Índex. By day 8 post coitus were observed significant morphometric changes at the vesicular lumen, height of the uterine wall of the mesometrial region and glandular lumen. For the same day important changes of the cellular mitotic Índex and apoptotic Index were observed. The rabbit could be a species used to predict normal embryo development, after the morphologic comprehension of the implantation, given its not so invasive form of implantation and its capacity of early placenta formation. Providing updated information...

Papel inmunológico de la progesterona en el mantenimiento del embarazo / Immunological role of progesterone in the maintenance of pregnancy

Progesterone is an essential hormone for pregnancy maintenance. This hormone acts by binding to its intracellular receptor or by rapid non-genomic actions to regulate a wide variety of biological functions in the feto-placental unit. Progesterone regulates blastocyst implantation and placental development by inducing immunosupression through type Th2 cytokines secretion. This review summarizes current research about the role of progesterone as critical regulator of expression and secretion of cytokines by T-cell and other placental cells.

La progesterona es una hormona esteroide muy versátil y esencial para el mantenimiento del embarazo. El principal mecanismo de acción de la progesterona es el clásico, vía receptor intracelular, regulando diversas funciones, aspectos celulares y vías moleculares implicadas en el proceso de la implantación. Asimismo existen mecanismos adicionales que no dependen de la interacción del complejo hormona receptor con la maquinaria transcripcional y que son capaces de regular rápidamente cascadas de señalización que determinarán la respuesta de la célula. En particular se ha demostrado que la progesterona ejerce efectos inmunosupresores durante la gestación al favorecer la secreción de citocinas de tipo Th2 por los linfocitos T, evento importante para regular el sistema inmunológico materno y evitar el rechazo de la placenta. El objetivo de esta revisión se centra en analizar la influencia de la progesterona en la interfase materno-fetal sobre la expresión y secreción de citocinas por las células T y no T como es el caso del trofoblasto.

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.

Predicting endometrium receptivity with parameters of spiral artery blood flow / 华中科技大学学报（医学）（英德文版）

In order To evaluate whether the parameters of spiral artery blood flow, as measured by transvaginal color Doppler, may be used to assess endometrium receptivity prior to embryo transfer (ET), a retrospective study of 94 infertile women who had undergone ART treatments with different outcomes (pregnant or nonpregnant) was done. Subendometrial blood flow was evaluated. The resistance index (RI), systolic/diastolic ratio (S/D) and pulsatility index (PI) were significantly lower in those who achieved pregnancy as compared with those who did not: 0.62+/-0.04 vs 0.68+/-0.04 (P0. 2, PI>1. , and S/D>3. , no pregnancy occurred. These data suggest that the parameters of spiral artery blood flow could be used as a new assay in predicting endometrial receptivity before ET.

Expression of nuclear factor-kappaB in mouse uterus during peri-implantation / 华中科技大学学报（医学）（英德文版）

To investigate the expression of the subunit p65 of NF-kappaB and inhibitor kappa B alpha (IkappaBalpha) in mouse uterus during peri-implantation, thereby investigating whether transient activation of nuclear factor-kappaB (NF-kappaB) takes place during embryo implantation in mice. Immunohistochemical technique was used to examine the expression and localization of p65 in endometrium or deciduas, and Western blot analysis was employed to detect the levels of IkappaBalpha protein in mouse endometrium or deciduas. P65 protein was detected in stromal cells, epithelial cells of endometrium as well as in myometrium. Staining was predominately seen in the cytoplasm of the cells. Staining intensity for p65 was stronger in the epithelial compartment than the stromal compartment and myometrium. Staining intensity increased slightly during pregnancy, and it reached a high level on pregnancy day 5 and day 8. In contrast to p65, the level of IkappaBalpha protein was lowest on pregnancy day 5 in all groups. Our results suggested that NF-kappaB may regulate embryo implantation by its transient activation in mice.

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.

Importancia de los radicales libres durante el ciclo reproductor / Importance of free radicals during the reproductive cycle

Los productos de la peroxidación, los radicales libres y los compuestos antioxidantes aumentan notablemente durante la ovulación, la implantación y a medida que transcurre la gestación. La concentración del radical anión superóxido (O2-) aumenta aproximadamente seis veces en el proestro, mientras que su enzima reguladora, la superóxido dismutasa, disminuye. La presencia del radical superóxido está relacionada con el edema y la proliferación celular del estro. Este radical también está relacionada con el aumento de la fluidez y polaridad de las membranas durante la implantación. A medida que evoluciona la preñez aumentan los productos de lipoperoxidación y los compuestos antioxidantes, sugiriendo que los lipoperóxidos durante esta etapa evocan a los mecanismos de defensa, de tal manera que al final de la gestación los antioxidantes superan a los fenómenos peroxidativos. Por otro lado, el radical óxido nítrico ha cobrado una gran importancia durante la gestación, ya que es considerado como uno de los relajantes mas potentes del músculo liso. La inhición de su síntesis provoca signos semejantes a los de pre-eclampsia y su administración logra revertir muchas alteraciones vasculares. El papel de los radicales libres no se limita a efectos nocivos, sino que oportunamente y en concentraciones adecuadas, éstos participan como inductores de factores de crecimientos o en la fluidez de las membranas

Participación de los factores de crecimiento en la reproducción humana / Growth factors participation in human reproduction

Los factores de crecimiento (FC) incluyen un grupo de moléculas peptídicas, con importantes efectos tróficos, mitóticos y de diferenciación celular sobre prácticamente todos los tejidos humanos. Se hace una revisión acerca de los diferentes FC, así como de sus efectos biológicos sobre los tejidos involucrados en el proceso reproductivo humano. Del mismo modo, se comenta la importancia de los FC en el desarrollo embrionario, así como en el proceso de la implantación. Finalmente, se valora la participación de los FC en la fisiopatología del síndrome de ovarios poliquísticos y de la endometriosis, a la luz de recientes investigaciones en estos campos. Se puede apreciar la importancia que los FC tienen como mediadores de diferentes hormonas (tanto en su secreción como en sus efectos biológicos), así como en la regulación de varios procesos celulares. Queda por establecer la utilidad de estos FC en la práctica cotidiana, por las limitantes tecnológicas inherentes a su identificación y cuantificación así como por la falta de más investigaciones clínicas en humanos. Sin embargo, parece tener un interesante potencial de aplicación en el manejo de problemas de esterilidad humana, así como en las diferentes técnicas de reproducción asistida, ya se in vivo o in vitro