scholarly journals A New Toolbox in Experimental Embryology—Alternative Model Organisms for Studying Preimplantation Development

2021 ◽  
Vol 9 (2) ◽  
pp. 15
Author(s):  
Claudia Springer ◽  
Eckhard Wolf ◽  
Kilian Simmet

Preimplantation development is well conserved across mammalian species, but major differences in developmental kinetics, regulation of early lineage differentiation and implantation require studies in different model organisms, especially to better understand human development. Large domestic species, such as cattle and pig, resemble human development in many different aspects, i.e., the timing of zygotic genome activation, mechanisms of early lineage differentiations and the period until blastocyst formation. In this article, we give an overview of different assisted reproductive technologies, which are well established in cattle and pig and make them easily accessible to study early embryonic development. We outline the available technologies to create genetically modified models and to modulate lineage differentiation as well as recent methodological developments in genome sequencing and imaging, which form an immense toolbox for research. Finally, we compare the most recent findings in regulation of the first lineage differentiations across species and show how alternative models enhance our understanding of preimplantation development.

2021 ◽  
Vol 22 (11) ◽  
pp. 5918
Author(s):  
Paweł Kordowitzki ◽  
Gabriela Sokołowska ◽  
Marta Wasielak-Politowska ◽  
Agnieszka Skowronska ◽  
Mariusz T. Skowronski

The oocyte is the major determinant of embryo developmental competence in all mammalian species. Although fundamental advances have been generated in the field of reproductive medicine and assisted reproductive technologies in the past three decades, researchers and clinicians are still trying to elucidate molecular factors and pathways, which could be pivotal for the oocyte’s developmental competence. The cell-to-cell and cell-to-matrix communications are crucial not only for oocytes but also for multicellular organisms in general. This latter mentioned communication is among others possibly due to the Connexin and Pannexin families of large-pore forming channels. Pannexins belong to a protein group of ATP-release channels, therefore of high importance for the oocyte due to its requirements of high energy supply. An increasing body of studies on Pannexins provided evidence that these channels not only play a role during physiological processes of an oocyte but also during pathological circumstances which could lead to the development of diseases or infertility. Connexins are proteins that form membrane channels and gap-junctions, and more precisely, these proteins enable the exchange of some ions and molecules, and therefore they do play a fundamental role in the communication between the oocyte and accompanying cells. Herein, the role of Pannexins and Connexins for the processes of oogenesis, folliculogenesis, oocyte maturation and fertilization will be discussed and, at the end of this review, Pannexin and Connexin related pathologies and their impact on the developmental competence of oocytes will be provided.


2000 ◽  
Vol 48 (3) ◽  
pp. 313-323 ◽  
Author(s):  
S. Cseh ◽  
László Solti

Biodiversity is increasingly threatened by intensive agriculture, environmental pollution, extinction of natural habitats and several other factors. Several mammalian species including ungulates have disappeared or are threatened by extinction. However, ungulates play an important role both in the ecosystem and in the economy. In general, species or breeds are considered endangered if their population does not exceed 1,000 individuals. In these cases conservation programmes should be initiated in order to maintain or even increase their number. This review deals with the possibilities and limitations of assisted reproductive technologies (ART) in the conservation of ecologically valuable wild, rare and indigenous ungulates. The methods discussed here are artificial insemination, cryopreservation of semen and embryos, embryo recovery and transfer,in vitroproduction of embryos, as well as micromanipulation techniques including sperm injection, assisted hatching and cloning. Some of these procedures are already being exploited in the breeding of farm ungulates, but more basic information about the reproductive patterns of wild, rare and indigenous animal species is needed before the routine use of ARTs.


2020 ◽  
Vol 3 ◽  
pp. 3
Author(s):  
Pramod K. Yadav ◽  
Anumegha Gupta ◽  
Alka Sharma ◽  
Anil Kumar Yadav ◽  
Meenakshi Tiwari ◽  
...  

Ovary has a fix number of germ cells during fetal life in mammals. The germ cells are depleted rapidly and a large number of germ cells (≥99%) are eliminated from the cohort of ovary through follicular atresia during prepubertal life. The various cell death pathways including apoptosis, autophagy, necrosis, and necroptosis are involved in follicular atresia. Hence, <1% of germ cells are culminated into oocytes that are available for meiotic maturation and ovulation during entire reproductive life. These oocytes are arrested at diplotene stage of meiotic prophase-I and remain arrested for few months to several years during entire reproductive life. Resumption from diplotene arrest in follicular oocytes starts in response to gonadotropins surge and progresses through metaphase-I to metaphase-II stage that extrudes first polar body at the time of ovulation. Surprisingly, oocytes do not wait for fertilizing spermatozoa and quickly undergo abortive spontaneous oocyte activation (SOA) in few mammalian species including humans. The abortive SOA makes oocyte unfit for fertilization and limits assisted reproductive technologies outcome. Indeed, majority of germ cells and oocytes are eliminated from the cohort of ovary and only few oocyte that are of good quality get selectively recruited to become right gamete after ovulation during entire reproductive life span in mammals.


2005 ◽  
Vol 75 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Christine Wrenzycki ◽  
Doris Herrmann ◽  
Andrea Lucas-Hahn ◽  
Claudia Gebert ◽  
Karin Korsawe ◽  
...  

2018 ◽  
Vol 30 (1) ◽  
pp. 203 ◽  
Author(s):  
A. Salama ◽  
M. Fathi ◽  
M. R. Badr ◽  
A. R. Moawad

In vitro embryo production (IVP) in the domestic bitch is important for conservation of endangered canids. Compared with various domestic animals, the development of assisted reproductive technologies (ART) in the dog has lagged behind, mainly due to the low percentage of oocytes that can reach metaphase II (MII) stage after in vitro maturation (IVM). Beneficial effects of l-carnitine (LC) on embryonic development in culture have been reported in many mammalian species; however, no studies have been conducted in dogs. The aim of the present study was to investigate the effect of LC supplementation during IVM of canine oocytes on nuclear maturation, fertilization status, and pre-implantation development following IVM/IVF. Cumulus-oocyte complexes (COC) were collected by slicing ovaries obtained from dogs (n = 20, 1 to 6 years of age) after ovariohysterectomy. The COC were subjected to IVM for 72 h in a medium (TCM-199) supplemented with LC at different concentrations (0.1, 0.3, 0.6, 1.0, or 2.0 mg mL−1) or without LC supplements (0 mg mL−1; control). Matured oocytes were fertilized in vitro with frozen–thawed spermatozoa, and presumptive zygotes were cultured in SOF medium for 7 days. Frequencies of nuclear maturation (72 h post-IVM), fertilization rates (18 h post-insemination), and embryo development (Days 2 to 5 post-insemination) were evaluated. Data were analysed by one-way ANOVA followed by Tukey’s multiple comparisons test. Supplementation of IVM medium with 0.3 or 0.6 mg mL−1 LC significantly improved (P ≤ 0.05) maturation (35.4% and 41.4%) and fertilization (21.3% and 25.8%) rates compared with the controls and with other LC-supplemented groups; values ranged from 20.1% to 25.0% for maturation and from 12.1% to 14.6% for fertilization. Cleavage (2- to 16-cell stages) was significantly higher (P ≤ 0.05) in the 0.6 mg mL−1 LC supplemented group than the 0.3 mg mL−1 supplemented group (16.3% v. 13.3%). These values were significantly higher (P ≤ 0.05) than those in other groups. Interestingly, 4.5% of IVM/IVF oocytes were developed to morula in 0.6 mg mL−1 LC supplemented group which was significantly higher (P ≤ 0.05) than those developed in the 0.3 mg mL−1 supplemented group (1.0%). No embryos developed beyond the 2- to 16-cell stage in the rest of the groups. In conclusion, l-carnitine supplementation during IVM is particularly efficient in improving nuclear maturation and pre-implantation embryo development of canine oocytes after IVF. These outcomes are important for the improvement of IVM conditions that can advance the efficiency of ART in dogs.


1996 ◽  
Vol 19 (2) ◽  
pp. 183
Author(s):  
D.A. Taggart ◽  
D. Schultz ◽  
P.D. Temple-Smith

Assisted reproductive technology is used routinely in management to treat infertility and in domestic species in basic husbandry. In eutherian mammals application of this technology is also well established in wildlife conservation programs. The development and application of this technology in marsupials, however, is a relatively new field. The reproductive techniques currently available for marsupial studies, their benefits and implications for conservation are discussed in order to remove any previous misconceptions and provide an insight into how these techniques might be applied. The potential of this technology for maintaining genetic variability and enhancing reproductive output of threatened marsupial species is highlighted, with particular reference to the conservation of rock wallabies.


2005 ◽  
Vol 17 (2) ◽  
pp. 15 ◽  
Author(s):  
Lawrence C. Smith ◽  
Jacob Thundathil ◽  
France Filion

Our fascination for mitochondria relates to their origin as symbiotic, semi-independent organisms on which we, as eukaryotic beings, rely nearly exclusively to produce energy for every cell function. Therefore, it is not surprising that these organelles play an essential role in many events during early development and in artificial reproductive technologies (ARTs) applied to humans and domestic animals. However, much needs to be learned about the interactions between the nucleus and the mitochondrial genome (mtDNA), particularly with respect to the control of transcription, replication and segregation during preimplantation. Nuclear-encoded factors that control transcription and replication are expressed during preimplantation development in mice and are followed by mtDNA transcription, but these result in no change in mtDNA copy number. However, in cattle, mtDNA copy number increases during blastocyst expansion and hatching. Nuclear genes influence the mtDNA segregation patterns in heteroplasmic animals. Because many ARTs markedly modify the mtDNA content in embryos, it is essential that their application is preceded by careful experimental scrutiny, using suitable animal models.


2019 ◽  
Vol 42 (1) ◽  
pp. 23-34
Author(s):  
Debora Groppetti ◽  
Alessandro Pecile ◽  
Stefano Frattini ◽  
Giulio Pagnacco ◽  
Silvana Arrighi

AbstractThe knowledge about ovarian physiology in small ruminants is still limited, especially when compared to other domestic species. Ovarian function in goats is mainly assessed by ultrasonographic techniques, whereas a quali-quantitative feature of the follicular and luteal structures throughout the reproductive cycle in naturally cycling goats is scarce. This study provides a detailed description of the functional morphology and size of 742 ovarian structures (follicles, corpora hemorrhagica and corpora lutea) in relation to the oestrus phase, the body weight and the age of 25 Alpine goats (Capra hircus). The current study demonstrated that, the number and size of the follicles were related to the stage of the reproductive cycle (P < 0.0001). Also, the mean number of follicles was high during both prepubertal anestrus and diestrus, whereas it was low in the oestrus. Large (3-4 mm in diameter) and very large follicles (> 4 mm) (P < 0.001), and small follicles (< 2 mm; P < 0.05) varied throughout the reproductive cycle, while medium follicles (2-3 mm) were invariably observed. Large and very large follicles were predominant during the diestrus phase and small follicles in the prepubertal anestrus. It is evident from the current study that the number of follicles (P < 0.05) was significantly affected with both body weight and age. On the other hand, the size of follicles was significantly affected with body weight only (P < 0.0001). These results could contribute to a deeper understanding of ovarian transformations with important implications in assisted reproductive technologies, thereby concurring in advancing the efficiency of ultrasound in breeding programs for this species.


2019 ◽  
Vol 101 (6) ◽  
pp. 1076-1082 ◽  
Author(s):  
Denis A Vaughan ◽  
Denny Sakkas

Abstract Natural sperm selection in humans is a rigorous process resulting in the highest quality sperm reaching, and having an opportunity to fertilize, the oocyte. Relative to other mammalian species, the human ejaculate consists of a heterogeneous pool of sperm, varying in characteristics such as shape, size, and motility. Semen preparation in assisted reproductive technologies (ART) has long been performed using either a simple swim-up method or density gradients. Both methodologies provide highly motile sperm populations; however neither replicates the complex selection processes seen in nature. A number of methods have now been developed to mimic some of the natural selection processes that exist in the female reproductive tract. These methods attempt to select a better individual, or population of, spermatozoa when compared to classical methods of preparation. Of the approaches already tested, platforms based upon sperm membrane markers, such as hyaluronan or annexin V, have been used to either select or deselect sperm with varied success. One technology that utilizes the size, motility, and other characteristics of sperm to improve both semen analysis and sperm selection is microfluidics. Here, we sought to review the efficacy of both available and emerging techniques that aim to improve the quality of the sperm pool available for use in ART.


Reproduction ◽  
2011 ◽  
Vol 142 (6) ◽  
pp. 793-801 ◽  
Author(s):  
Heide Schatten ◽  
Qing-Yuan Sun

In non-rodent mammalian species, including humans, the oocyte and sperm both contribute centrosomal components that are most important for successful fertilization. Centrosome pathologies in sperm and the oocyte can be causes for infertility which may be overcome by assisted reproductive technologies based on proper diagnosis of specific centrosomal pathologies. However, we do not yet fully understand the cell and molecular mechanisms underlying centrosome functions in germ cells and in the developing embryo, which calls for directed specific investigations to identify centrosome-related pathologies that include components in sperm, egg, or centrosome regulation within the fertilized oocyte. The present review highlights cellular and molecular aspects of centrosomes and centrosome–nuclear interactions focused on nuclear mitotic apparatus protein during fertilization and proposes future directions in expanding therapeutic approaches related to centrosome pathologies that may play a role in still unexplained causes of infertility.


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