Dissection of the Ovulatory Process Using ex vivo Approaches

Finishing the egg

Gamete development is a fundamental process that is highly conserved from early eukaryotes to mammals. As germ cells develop, they must coordinate a dynamic series of cellular processes that support growth, cell specification, patterning, the loading of maternal factors (RNAs, proteins, and nutrients), differentiation of structures to enable fertilization and ensure embryonic survival, and other processes that make a functional oocyte. To achieve these goals, germ cells integrate a complex milieu of environmental and developmental signals to produce fertilizable eggs. Over the past 50 years, Drosophila oogenesis has risen to the forefront as a system to interrogate the sophisticated mechanisms that drive oocyte development. Studies in Drosophila have defined mechanisms in germ cells that control meiosis, protect genome integrity, facilitate mRNA trafficking, and support the maternal loading of nutrients. Work in this system has provided key insights into the mechanisms that establish egg chamber polarity and patterning as well as the mechanisms that drive ovulation and egg activation. Using the power of Drosophila genetics, the field has begun to define the molecular mechanisms that coordinate environmental stresses and nutrient availability with oocyte development. Importantly, the majority of these reproductive mechanisms are highly conserved throughout evolution, and many play critical roles in the development of somatic tissues as well. In this chapter, we summarize the recent progress in several key areas that impact egg chamber development and ovulation. First, we discuss the mechanisms that drive nutrient storage and trafficking during oocyte maturation and vitellogenesis. Second, we examine the processes that regulate follicle cell patterning and how that patterning impacts the construction of the egg shell and the establishment of embryonic polarity. Finally, we examine regulatory factors that control ovulation, egg activation, and successful fertilization.

Effect of indomethacin on embryo implantation and histomorphology of uterus, ovary, kidney, and liver of rats

Background

This study aimed to determine the effects of Indomethacin (IMC) treatment on embryo implantation and histomorphology of uterus, ovary, and other vital organs and its effective dosage in establishing embryo implantation dysfunction model in Sprague-Dawley (SD) rats.

Materials and Methods

The experiments were performed on 24 (6 × 4 groups) adult female SD rats aged 12 weeks old. G1 was the control group and received a normal diet with normal saline. However, on pregnancy days 3 (Pd3) and 4 (Pd4), G2, G3, and G4 were given normal saline and subcutaneously administered IMC twice daily at different doses of 4.33, 4.66 and 5.00 mg/kg body weight, respectively. The rats were euthanized on day 8 of pregnancy (Pd8). The uterus was excised and examined for signs of pregnancy, followed by tissue samples from liver, kidney, and ovary (for histomorphological examination using haematoxylin and eosin stain).

Results

All IMC treatment doses disrupted the implantation process and caused a significant reduction in embryo development. Analysis for histopathological changes revealed that IMC doses above 4.33 mg/kg body weight caused more adverse reproductive health effects in rats. Vasoconstriction and micro vascularization were detected in the liver, while degenerative Bowman's capsules and inflammatory cells were observed in kidney sections from IMC-treated rats.

Conclusion

IMC therapy interfered with implantation and embryo development in rats, resulting in significant uterine vasoconstriction and atrophy, 4.33 mg/kg bwt dose appeared to be optimum to establish embryo implantation dysfunction in SD rats.

Mechanobiology of the female reproductive system

BACKGROUND

Mechanobiology in the field of human female reproduction has been extremely challenging technically and ethically.

METHODS

The present review provides the current knowledge on mechanobiology of the female reproductive system. This review focuses on the early phases of reproduction from oocyte development to early embryonic development, with an emphasis on current progress.

MAIN FINDINGS RESULTS

Optimal, well-controlled mechanical cues are required for female reproductive system physiology. Many important questions remain unanswered; whether and how mechanical imbalances among the embryo, decidua, and uterine muscle contractions affect early human embryonic development, whether the biomechanical properties of oocytes/embryos are potential biomarkers for selecting high-quality oocytes/embryos, whether mechanical properties differ between the two major compartments of the ovary (cortex and medulla) in normally ovulating human ovaries, whether durotaxis is involved in several processes in addition to embryonic development. Progress in mechanobiology is dependent on development of technologies that enable precise physical measurements.

CONCLUSION

More studies are needed to understand the roles of forces and changes in the mechanical properties of female reproductive system physiology. Recent and future technological advancements in mechanobiology research will help us understand the role of mechanical forces in female reproductive system disorders/diseases.