Mammalian fertilization is a highly complex and finely regulated process that involves sperm-oocyte fusion and subsequent cell fate decisions. This article reviews the molecular mechanisms underlying pronucleus formation and disappearance during mammalian fertilization, with particular focus on the key molecules and regulatory mechanisms involved in these processes. It further discusses how failures in pronucleus formation and disappearance may lead to abnormal embryonic development and various infertility issues, along with potential solutions to address these abnormalities. The aim is to provide a theoretical foundation for understanding the molecular mechanisms that contribute to abnormal pronucleus formation and disappearance in the context of reproductive biology and assisted reproductive technology, while also highlighting potential directions for future research.

Mammalian fertilization is a highly complex and finely regulated process that involves sperm-oocyte fusion and subsequent cell fate decisions. This article reviews the molecular mechanisms underlying pronucleus formation and disappearance during mammalian fertilization, with particular focus on the key molecules and regulatory mechanisms involved in these processes. It further discusses how failures in pronucleus formation and disappearance may lead to abnormal embryonic development and various infertility issues, along with potential solutions to address these abnormalities. The aim is to provide a theoretical foundation for understanding the molecular mechanisms that contribute to abnormal pronucleus formation and disappearance in the context of reproductive biology and assisted reproductive technology, while also highlighting potential directions for future research.

Cryopreservation of human germ cells as a form of fertility preservation plays an important role in the development of assisted reproductive technology (ART), which has become one of the research hotspots in the field of reproductive medicine and is increasingly used in assisted reproductive practice. To improve the success rate of ART, cryopreservation techniques are constantly being improved in development, especially the selection of freezing strategies and the improvement and optimization of cryoprotectants. Cryopreservation is indicated for groups undergoing ART or for the freezing and preservation of oocytes, sperm and embryos due to reduced fertility caused by disease. It is also indicated for the cryopreservation of ovarian and testicular tissue for fertility preservation in cancer patients. However, the freezing effect of different freezing methods is not consistent for different germ cell types, and there is a lack of reasonable and valid criteria for evaluating the freezing effect of different germ cells. This paper reviews the current development and application of cryopreservation technology for human germ cells and discusses the future development of cryopreservation.

Cryopreservation of human germ cells as a form of fertility preservation plays an important role in the development of assisted reproductive technology (ART), which has become one of the research hotspots in the field of reproductive medicine and is increasingly used in assisted reproductive practice. To improve the success rate of ART, cryopreservation techniques are constantly being improved in development, especially the selection of freezing strategies and the improvement and optimization of cryoprotectants. Cryopreservation is indicated for groups undergoing ART or for the freezing and preservation of oocytes, sperm and embryos due to reduced fertility caused by disease. It is also indicated for the cryopreservation of ovarian and testicular tissue for fertility preservation in cancer patients. However, the freezing effect of different freezing methods is not consistent for different germ cell types, and there is a lack of reasonable and valid criteria for evaluating the freezing effect of different germ cells. This paper reviews the current development and application of cryopreservation technology for human germ cells and discusses the future development of cryopreservation.

OBJECTIVE: To compare the prevalence of chromosomal aneuploidies and pregnancy outcomes of D5 and D6 blastocysts subjected to preimplantation genetic testing for aneuploidy (PGT-A). METHODS: Clinical and laboratory data of 268 couples who underwent PGT-A at the Reproductive Center of the First Affiliated Hospital of Zhengzhou University from September 2018 to September 2020 were collected. The prevalence of chromosomal aneuploidies and pregnancy outcomes of D5/D6 biopsied blastocysts were compared. RESULTS: Compared with D6 blastocysts, the euploidy rate of D5 blastocysts was significantly higher (49.1% vs. 41.1%, P = 0.001 1), whilst their aneuploidy rate was significantly lower (50.9% vs. 58.9%, P = 0.001 1). The rate of numerical abnormalities of D6 blastocysts was significantly higher than that of D5 blastocysts (27.9% vs. 20.2%, P = 0.000 5). For patients under 35 years old, the euploidy rate of D5 blastocysts was significantly higher than that of D6 blastocysts (53.8% vs. 44.3%, P = 0.001), whilst the numerical abnormality rate was significantly lower (16.3% vs. 23.9%, P = 0.001). For both D5 and D6 blastocysts, the euploidy rates for patients <= 35 were significantly higher than those for > 35. The elder group had the lowest rates for aneuploidies and live births. Compared with those receiving D6 blastocysts transplantation, the pregnancy rate, implantation rate and live birth rate for those receiving thawed D5 blastocysts transplantation were significantly higher (60.2% vs.37.0%, P = 0.000 3; 59.1% vs.37.0%, P = 0.000 6; 47.7% vs. 28.3%, P = 0.002). CONCLUSION For patients undergoing PGT-A, the chromosomal euploidy rate for D5 blastocysts is higher than that for D6 blastocysts, and the clinical outcome of D5 blastocysts with normal signal is better than that of D6 blastocysts. Elder patients have a higher rate of aneuploidies.
Female ; Pregnancy ; Humans ; Aged ; Adult ; Pregnancy Outcome ; Aneuploidy ; Blastocyst ; Genetic Testing ; Laboratories

In vitro maturation (IVM) technology is a reproductive technology that induces the maturation of cumulus-oocyte complexes to the MⅡ stage in vitro. Since the application of IVM technology, in order to improve the IVM rate of immature oocytes, the culture system has been continuously improved in the development, including the improvement of culture program and culture medium, and the optimization of culture environment, and a biphasic IVM protocol with higher oocyte maturation rate than conventional IVM protocol has been developed, with the effectively improvement of IVM clinical pregnancy rate. IVM technology has been widely used in patients with polycystic ovary syndrome to avoid ovarian hyperstimulation, and in patients with ovarian resistance syndrome who have ovarian reserve but do not respond to exogenous gonadotropins. Combined with a variety of fertility preservation technologies, it is also suitable for cancer patients who want fertility preservation. This view summarized the current development status and application progress of IVM technology, and makes a brief summary of the future direction of IVM.

In vitro maturation (IVM) technology is a reproductive technology that induces the maturation of cumulus-oocyte complexes to the MⅡ stage in vitro. Since the application of IVM technology, in order to improve the IVM rate of immature oocytes, the culture system has been continuously improved in the development, including the improvement of culture program and culture medium, and the optimization of culture environment, and a biphasic IVM protocol with higher oocyte maturation rate than conventional IVM protocol has been developed, with the effectively improvement of IVM clinical pregnancy rate. IVM technology has been widely used in patients with polycystic ovary syndrome to avoid ovarian hyperstimulation, and in patients with ovarian resistance syndrome who have ovarian reserve but do not respond to exogenous gonadotropins. Combined with a variety of fertility preservation technologies, it is also suitable for cancer patients who want fertility preservation. This view summarized the current development status and application progress of IVM technology, and makes a brief summary of the future direction of IVM.

With the increasing incidence of infertility worldwide, the impact of nutrients on reproductive health has received increasing attention. Many research results indicate that nutritional status and daily nutrient intake have very important effects on female fertility. Malnutrition or excess nutrition, especially the balance of trace elements, vitamins and three nutrients including carbonhydrates, lipids and proteins in the body are closely related to female reproductive function, affecting almost the whole reproductive process including female ovarian reserve, oocyte development, fertilization, embryo development and embryo implantation. This paper summarized the effects of nutrition status and main nutrients on female reproductive function.

With the increasing incidence of infertility worldwide, the impact of nutrients on reproductive health has received increasing attention. Many research results indicate that nutritional status and daily nutrient intake have very important effects on female fertility. Malnutrition or excess nutrition, especially the balance of trace elements, vitamins and three nutrients including carbonhydrates, lipids and proteins in the body are closely related to female reproductive function, affecting almost the whole reproductive process including female ovarian reserve, oocyte development, fertilization, embryo development and embryo implantation. This paper summarized the effects of nutrition status and main nutrients on female reproductive function.

With the increasing incidence of infertility in the world, the impact of environmental factors, lifestyles and nutrients on reproductive health has gradually attracted attention. Many studies have shown that there is a significant correlation between the intake of nutrients and semen quality. A variety of nutrients, including micronutrients, vitamins, amino acids and derivatives, plant-derived extracts, melatonin, have effects in male spermatogenesis and semen parameters, and the types and content of nutrients in the body are also significantly related to male semen quality. This article reviews the effects and mechanisms of nutrients on men spermatogenesis and semen quality.