Embryonic-placental relationship in Lagostomus maximus as compared to other hystricognath rodents and eutherian mammals

Reproductive specializations in caviomorphs (infraorder Hystricognathi), are very peculiar within the Order Rodentia. These include long gestations, the birth of offspring with an extreme degree of precociality, and short lactation periods. This study describes the embryo-placental relationship of viable implantation sites (IS) of the plains viscacha, Lagostomus maximus, after 46 post-coital days. The observations recorded in this study are comparatively discussed with those of other hystricognaths and eutherians. At this stage, the embryo resembles that of other eutherians. At this time of embryo development, the placenta exhibits a size, shape, and organization similar to that it will have in its mature state. Besides, the subplacenta is already highly folded. These characteristics are adequate to sustain the development of future precocial offspring. The mesoplacenta, a structure present in other hystricognaths and related to uterine regeneration is described for the first time in this species. This detailed description of the placental and embryonic structure contributes to the knowledge of the reproductive and developmental biology of the viscacha, as well as that of hystricognaths. These characteristics will allow testing other hypotheses related to the morphology and physiology of the placenta and subplacenta, and their relationship with the growth and development of precocial offspring in Hystricognathi.Fil: Acuña, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada (LHYEDEC);Fil: Portiansky, Enrique Leo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Miglino, María Angélica. Universidade de Sao Paulo; BrasilFil: Flamini, Mirta Alicia. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada (LHYEDEC);Fil: Barbeito, Claudio Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Laboratorio de Histología y Embriología Descriptiva, Experimental y Comparada (LHYEDEC)

La membrana vitelina de embriones bovinos, un modelo experimental de interés para estudios proteómicos.Análisis del perfil proteico mediante electroforesis bidimensional

Comunicaciones a congreso

Study of embryonic death in mammals through an unconventional model: Lagostomus maximus, plains viscacha (Rodentia, Chinchillidae)

Lagostomus maximus es un roedor histricomorfo con características reproductivas muy peculiares, entre ellas, la poliovulación de 200-800 ovocitos/estro y una tasa de resorción embrionaria del 80%, que involucra a las implantaciones craneales y medias. Habiendo realizado numerosos estudios estructurales sobre todos los órganos y en diferentes momentos de la vida reproductiva de las hembras, decidimos estudiar la muerte embrionaria que se observa en esta especie. Recientemente, los diferentes análisis realizados en fetos y hembras adultas demostraron la heterogeneidad de los cuernos uterinos en sentido craneocaudal. A partir de estos resultados se construyó la hipótesis de cómo la heterogeneidad estructural podría influir en la supervivencia diferencial de las implantaciones embrionarias, que finalmente origina la muerte de las implantaciones craneales y medias y permite la viabilidad de las caudales. Si bien la heterogeneidad uterina también se observa en otros mamíferos, en ninguna de estas especies estudiadas la masividad de las implantaciones afectadas es similar a lo observado en Lagostomus maximus. La caracterización de las implantaciones, en resorción y viables, y sus similitudes a las observadas en modelos experimentales, permiten considerar a la vizcacha como un modelo no convencional para el estudio de la muerte embrionaria y/o enfermedades asociadas con la preñez.Lagostomus maximus is a histricomorphic rodent with very peculiar reproductive characteristics, including polyovulation of 200-800 oocytes/estrus and an embryo resorption rate of 80%, which involves cranial and middle implantations. Having carried out numerous structural studies on all the organs and at different moments of the reproductive life of the females, we decided to study the embryonic death observed in this species. Recently, the different analyzes carried out in fetuses and adult females demonstrated the heterogeneity of the uterine horns in the craniocaudal direction. Based on these results, the hypothesis of how structural heterogeneity could influence the differential survival of embryonic implantations, which ultimately causes the death of cranial and middle and allows the viability of the caudal implantations was constructed. Although uterine heterogeneity is also observed in other mammals, in none of these species is the massiveness of the affected implants like that observed in Lagostomus maximus. The characterization of implantations, in resorption and viable, and their similarities to those observed in experimental models, allow us to consider viscacha as an unconventional model for the study of embryonic death and/or diseases associated with pregnancy.Fil: Acuña, Francisco. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barbeito, Claudio Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Miglino, María Angélica. Universidade de Sao Paulo; BrasilFil: Ranea, Guadalupe. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; ArgentinaFil: Nishida, Fabian. Universidad Nacional Arturo Jauretche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Portiansky, Enrique Leo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Academia Nacional de Agronomía y Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Flamini, Mirta Alicia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Histología y Embriología; Argentin

Spontaneous embryonic death in plains viscacha (Lagostomus maximus - Rodentia), a species with unique reproductive characteristics

Spontaneous embryonic death is a conserved reproductive event in Eutherians. The macro and microscopic characteristics of this type of death are similar between the different taxa. However, in the hystricomorphic rodent plains viscacha (Lagostomus maximus) is exceptional in terms of massiveness (80% embryonic resorption). In this species, of the 10–12 implantation sites (IS) (half in each uterine horn), only the caudal embryos will survive, resorbing the cranial and intermediate IS. We hypothesize that uterine structural variations in L. maximus restrict growth and promote embryo death, with the consequent loss of placental homeostasis in the cranial and middle IS. In this study, different studies (ultrasonography, macroscopy and microscopy) were carried out to analyze different aspects of the intermediate gestation of L. maximus (46 days postcoitus). Ultrasonographic studies revealed that the cranial and middle IS (IS-1, IS-2, and IS-3) had no recognizable embryonic and placental structures as compared to the caudal implantation sites (IS-4). Macroscopically, the areas corresponding to the embryos in the cranial and middle IS were occupied by a necrotic black semi-fluid mass. Moreover, the placenta in these IS was undifferentiated. However, in the caudal IS both the embryo and its placenta were distinguishable. Using histological and immunohistochemical techniques, it was observed that the placentas of IS-1, IS-2 and IS-3 were disorganized and showed hemorrhage, inflammatory infiltration containing neutrophils, macrophages, mast cells and foreign body giant cells, apoptotic trophoblast, and a layer of collagen fibers and fibroblasts that circumscribed each of these IS. In contrast, the placenta of the caudal IS showed an organized maternal-embryonic interface. The characteristics observed in IS in resorption of viscachas in intermediate gestation show that, regardless of gestation time, embryonic death has a similar macro and microscopic morphological pattern among eutherians with invasive placentation. However, the massiveness and sectorization of embryonic death in the plains viscacha make the species a unique model for the study of this reproductive event.Fil: Acuña, Francisco. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología General Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Barbeito, Claudio Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología General Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Portiansky, Enrique Leo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología General Veterinaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Ranea, Guadalupe. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología General Veterinaria; ArgentinaFil: Miglino, María Angélica. Universidade de Sao Paulo; BrasilFil: Flamini, Mirta Alicia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología General Veterinaria; Argentin

Study of embryonic death in mammals through an unconventional model: Lagostomus maximus, plains viscacha (Rodentia, Chinchillidae)

Lagostomus maximus es un roedor histricomorfo con características reproductivas muy peculiares, entre ellas, la poliovulación de 200-800 ovocitos/estro y una tasa de resorción embrionaria del 80%, que involucra a las implantaciones craneales y medias. Habiendo realizado numerosos estudios estructurales sobre todos los órganos y en diferentes momentos de la vida reproductiva de las hembras, decidimos estudiar la muerte embrionaria que se observa en esta especie. Recientemente, los diferentes análisis realizados en fetos y hembras adultas demostraron la heterogeneidad de los cuernos uterinos en sentido craneocaudal. A partir de estos resultados se construyó la hipótesis de cómo la heterogeneidad estructural podría influir en la supervivencia diferencial de las implantaciones embrionarias, que finalmente origina la muerte de las implantaciones craneales y medias y permite la viabilidad de las caudales. Si bien la heterogeneidad uterina también se observa en otros mamíferos, en ninguna de estas especies estudiadas la masividad de las implantaciones afectadas es similar a lo observado en Lagostomus maximus. La caracterización de las implantaciones, en resorción y viables, y sus similitudes a las observadas en modelos experimentales, permiten considerar a la vizcacha como un modelo no convencional para el estudio de la muerte embrionaria y/o enfermedades asociadas con la preñez.Lagostomus maximus is a histricomorphic rodent with very peculiar reproductive characteristics, including polyovulation of 200-800 oocytes/estrus and an embryo resorption rate of 80%, which involves cranial and middle implantations. Having carried out numerous structural studies on all the organs and at different moments of the reproductive life of the females, we decided to study the embryonic death observed in this species. Recently, the different analyzes carried out in fetuses and adult females demonstrated the heterogeneity of the uterine horns in the craniocaudal direction. Based on these results, the hypothesis of how structural heterogeneity could influence the differential survival of embryonic implantations, which ultimately causes the death of cranial and middle and allows the viability of the caudal implantations was constructed. Although uterine heterogeneity is also observed in other mammals, in none of these species is the massiveness of the affected implants like that observed in Lagostomus maximus. The characterization of implantations, in resorption and viable, and their similarities to those observed in experimental models, allow us to consider viscacha as an unconventional model for the study of embryonic death and/or diseases associated with pregnancy.Academia Nacional de Agronomía y Veterinari

Term placenta of the southern elephant seal (Mirounga leonina)

Introduction: The pinnipeds’ placenta has been described as zonary, annular, labyrinthic and endotheliochorial, like that of the terrestrial carnivores. This article describes the placenta of Mirounga leonina, a phocid pinniped, focusing on some morphological features related to fetal nutrition. Methods: Placental samples from three elephant seals were collected and conditioned after natural delivery at the Antarctic Specially Protected Area 132. Histological and ultrastructural studies were conducted; cytokeratins, vimentin, α-smooth muscle actin, and desmin proteins were detected using immunohistochemistry. Results: The placentas were zonary, lobed, belt-shaped, and showed multiple vivid orange areas, which corresponded to bilirubin crystalline pigment found among chorionic villi and inside trophoblast cells. In the labyrinth, cytotrophoblast cells were isolated and there was a scant syncytium interposed between maternal and fetal vessels. Fetal vessels were small, round, and frequently intratrophoblastic, while maternal vessels were large, irregular, sinuous, and thin-walled. Vimentin and actin were detected in some scattered non-vascular cells throughout the labyrinth. Broad areas of degenerated and necrotic maternal components were also observed. Discussion: The placentas of pinniped and fissiped carnivores share several traits. However, some remarkable features might maximize respiratory efficiency, collaborating to endure deep-diving hypoxia. Some of them, as the notably large sinuous maternal capillaries and fetal capillary indentation into the syncytium, are shared, e.g., by Phocidae and Mustelidae. Besides hemotropic nutrition taking place through an extremely narrow barrier, the abundant necrotic material and hematic products might allow substantial endocytosis of detritus even in term placentas, in this species giving birth to precocious offspring.Fil: Diessler, Mónica Elizabeth. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Migliorisi, Ana Lorena. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Gomez Castro, María Gimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Favaron, Phelipe Oliveira. Universidade de Sao Paulo; BrasilFil: Zanuzzi, Carolina Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Negrete, Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Direcciñon Nacional del Antartico. Instituto Antártico Argentino. Departamento de Biología de Predadores Tope; ArgentinaFil: Miglino, María Angélica. Universidade de Sao Paulo; BrasilFil: Barbeito, Claudio Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentin

Key characteristics of the ovary and uterus for reproduction with particular reference to poly ovulation in the plains viscacha (Lagostomus maximus, chinchillidae)

One of the dogmas of mammalian reproduction states is that primordial germ cells in females are restricted to the intrauterine phase, and that only a small portion of oocytes is available for ovulation during the adult life. Among the rare exceptions to this rule is the plains viscacha. This specie polyovulates up to 800 oocytes per cycle, from which 10 to 12 are implanted, but only 1e2 conceptuses survive. To better understand the key mechanisms of this pattern of embryonic to uterine interactions, we analyzed 19 female genital systems by means of gross morphology, histology, stereology and immunohistochemistry. Data showed that a specialized, highly convoluted structure of the ovarian cortex developed during the intrauterine phase as a prerequisite for the massive super-ovulation, likely associated with the inhibition of apoptosis and continued proliferation of germ cells, as well as maintenance of several corpora lutea during the adult life. In addition, specializations of uterine vasculature and musculature were demonstrated. Altogether, these key morphological characteristics evolved in order to contribute as compensatory or controlling mechanism for polyovulation and polyimplantation that led these species into becoming an unique enigma in reproductive biology, and a potential animal model to provide explanations regarding to developmental specializations.Fil: Flamini, Mirta Alicia. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Barreto, Rodrigo da Silva Nunes. Universidade de Sao Paulo; BrasilFil: Matias, Gustavo De Sá Schiavo. Universidade de Sao Paulo; BrasilFil: Birbrair, Alexander. Universidade Federal de Minas Gerais; BrasilFil: Harumi de Castro Sasahara, Tais. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Barbeito, Claudio Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Miglino, María Angélica. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentin