Reproduction, Fertility and Development
Number 7 2014
In vitro follicle culture can be accomplished using two- or three-dimensional systems. This review focuses on three-dimensional in vitro culture systems based on the use of alginate hydrogel and its importance for the maintenance of follicular architecture, which is essential to ensure appropriate interactions between granulosa cells and the oocyte. Such a culture system has many important applications including its use in assisted reproductive technology.
To improve embryo in vitro production techniques, is necessary to understand the variables involved in the process. In the present study, we investigated the control of the pentose phosphate pathway (PPP), a key metabolic pathway involved in NADPH and ribose synthesis, in cumulus–oocytes complexes during IVM and revealed a link between PPP activity and oxidative and mitochondrial metabolism of the oocyte. These findings will help us understand the relationship between the PPP in cumulus cells and events related with the maturational capability of the oocyte.
Deficiencies in porcine embryo elongation contribute to approximately 20% of embryonic loss, but exact mechanisms of elongation are poorly understood. We have established a culture system using alginate hydrogel as a three-dimensional matrix that facilitates morphological changes with increased oestrogen production and differential gene expression of porcine embryos, consistent with in vivo elongation. This alginate culture system can serve as a tool for evaluating specific mechanisms of embryo elongation.
The subtle manner of embryo–oviductal communications in the horse is very difficult to analyse in vivo. Therefore, we developed a system sustaining equine oviduct explants, bordered by highly differentiated, functional and intact epithelial cells, with only a negligible percentage of apoptotic or necrotic cells and so mimicking the in vivo situation very closely. Since the system is easy to set up, it appears to be an excellent tool for proteome, transcriptome and miRNome analysis, in order to unravel embryo–maternal interactions in the horse.
Maternal nutritional status during pregnancy is essential for normal growth, as intra-uterine development is dependent on the nutritional, hormonal and metabolic environment provided by the mother. We investigated the effects of gestational protein restriction on prostate morphogenesis in male rats and the results showed that maternal malnutrition delayed prostate development. This result could be an important factor in altered postnatal development and long-term diseases in the prostate.
The critical role of autophagy has been demonstrated in mammalian early embryogenesis. The present study was conducted to elucidate the effect of rapamycin, a chemical autophagy inducer, on the nuclear and cytoplasmic maturation of porcine oocytes. We revealed that autophagy induction by rapamycin could improve the rate of MII oocyte production, monospermic fertilization, blastocyst formation rate, total cell number and cell survival.
Controlled ovarian hyperstimulation, commonly involved in fertility treatment, is associated with an altered uterine environment, making it less receptive to an implanting blastocyst. A rat ovarian hyperstimulation model used in this study showed an increase in AQP5 water channels and a decrease in a tight junction protein, claudin-4, in the uterus at the time of implantation. These results suggest that there is an alteration in uterine luminal fluid dynamics and content at the time of implantation in the ovarian hyperstimulated rat.
Androgens are essential for the initiation and maintenance of reproduction in mammals. Androgens act via androgen receptors (AR) and can regulate the function of a variety of cells in a number of organs, including pituitary cells secreting gonadotropins (LH and FSH). In the present study we saw a decrease in pituitary cells expressing AR, LH and FSH, and in cells coexpressing FSH and AR, in castrated male viscachas. These findings suggest that androgens could differentially affect the LH-and FSH-secreting cells.
There is the possibility for a woman to cryopreserve and store her own eggs in an egg bank until she is ready to proceed with motherhood. Autologous follicular fluid supplemented with ethylene glycol and sucrose was an efficient cryoprotectant for egg cryopreservation; the frozen–thawed eggs have similar potential for fertilisation and development as that of fresh eggs. This simple, feasible method for egg cryopreservation can be popularised in all reproductive centres.
Leukotrienes (LTs) are pro-inflammatory lipid mediators and their production in inflamed uteri is not fully understood. The present experiment aimed to determine LTB4 and LTC4 amounts and 5-lipooxygenase, LTA4 hydrolase and LTC4 synthase mRNA levels and protein expression in the porcine uteri with inflammation. The data obtained show the upregulation of LT synthesis and secretion in inflamed porcine uteri, which suggests the importance of these factors for functions of pathologically changed organs.
Incomplete reprograming of somatic cells is one of the important reasons for the low efficiency of somatic cell nuclear transfer (SCNT). In our study we investigated the reprogramming effect of Xenopus egg extract on somatic donor cells from pig used subsequently for SCNT, and our results showed that a single extract treatment produces a long-term increase in in vitro efficiency of SCNT. Our findings provide new understandings about the process of cellular reprogramming and also have potential application for future work on practical SCNT.
A suboptimal pregnancy environment that reduces birth weight has the potential to program disease in subsequent generations. The aim of the study was to examine transgenerational cardio-renal effects, via the maternal line, using a rat model of uteroplacental insufficiency. We report alterations to kidney development and transient, sex-specific hypertension in second generation offspring. This study demonstrates that in utero exposures can have far-reaching effects that extend into the next generation.
Male infertility has become a social and medical problem of developed countries over the last decades. This work reports the differences in degree of fibronectin fragmentation and its domain reactivities in seminal plasmas of fertile normozoospermic and infertile leucocytospermic male patients. It is expected that the analysis of human seminal fibronectin molecular status would be helpful for selecting the highest quality spermatozoa for use in assisted reproduction techniques.
Preterm birth is typically associated with infection and/or inflammation, and being accountable for approximately 1 million annual neonatal deaths, is a global healthcare issue. We found that spontaneous preterm labour is associated with a decrease in transcription factor FOXM1 in fetal membranes, with FOXM1 gene silencing in primary amnion cells increasing inflammation-induced pro-labour mediators. The role of FOXM1 in labour processes enhances our understanding of the mechanisms that drive preterm birth, perhaps leading to a future clinical therapeutic.