Evaluation of uterine receptivity after gonadotropin releasing hormone agonist administration as an oocyte maturation trigger: a rodent model.

In natural cycle or minimal stimulation cycle IVF, buserelin acetate (buserelin), a gonadotropin-releasing hormone agonist, is often used as a maturation trigger; however, its effect on pregnancy outcomes remains unclear. Therefore, in the present study, we compared uterine receptivity in buserelin-administered mice with that in human chorionic gonadotropin (hCG)-administered mice during the peri-implantation period. Implantation, decidualisation, and term-pregnancy were impaired following hCG, but not buserelin administration. hCG stimulated the synthesis and secretion of progesterone and oestradiol, whereas ovarian steroidogenesis in the buserelin-treated group was comparable with that in the control group. Furthermore, similar to the observation in controls, the buserelin-treated group exhibited activation of progesterone receptor signalling and inhibition of oestrogen receptor signalling in the endometrial epithelium on the day of implantation. However, epithelial progesterone signalling was not detected, and a high expression of genes downstream to oestrogen was observed on day 4 following hCG administration. These results suggest that buserelin administration does not impact uterine receptivity as it did not affect ovarian steroidogenesis and endometrial steroid signalling. Therefore, buserelin is preferred as an oocyte maturation trigger to optimise uterine receptivity during treatments involving timed intercourse, intrauterine insemination, or fresh embryo transfer following in vitro fertilisation.

Hydroxypropyl cellulose as an option for supplementation of cryoprotectant solutions for embryo vitrification in human assisted reproductive technologies.

Hydroxypropyl cellulose (HPC) was investigated as a replacement for serum substitute supplement (SSS) for use in cryoprotectant solutions for embryo vitrification. Mouse blastocysts from inbred (n = 1056), hybrid (n = 128) strains, and 121 vitrified blastocysts donated by infertile patients (n = 102) were used. Mouse and human blastocysts, with or without zona pellucida, were vitrified and warmed in either 1% or 5% HPC or in 5% or 20% SSS-supplemented media using the Cryotop (Kitazato BioPharma Co. Ltd, Fuji, Japan) method, and the survival and oxygen consumption rates were assessed. Viscosity of each vitrification solution was compared. Survival rates of mouse hybrid blastocysts and human zona pellucida-intact blastocysts were comparable among the groups. Mouse and human zona pellucida-free blastocysts, which normally exhibit poor cryoresistance, showed significantly higher survival rates in 5% HPC than 5% SSS (P < 0.05). The 5% HPC-supplemented vitrification solution showed a significantly higher viscosity (P < 0.05). The blastocysts were easily detached from the Cryotop strip during warming when HPC-supplemented vitrification solution was used. The oxygen consumption rates were similar between non-vitrified and 5% HPC groups. The results suggest possible use of HPC for supplementation of cryoprotectant solutions and provide useful information to improve vitrification protocols.

Long-term adverse effects of cyclophosphamide on follicular growth and angiogenesis in mouse ovaries.

The adverse effects of the anti-cancer agent cyclophosphamide (CTX) on follicular growth and ovarian angiogenesis were investigated in mice. CTX treatment irreversibly induced a loss of follicles through apoptosis and decreased microvascularization of the corpora lutea and follicles in a dose-dependent manner. Our findings demonstrated that CTX adversely affected the ovaries indicating the need to support an awareness of fertility preservation before chemotherapy is initiated.

Ovarian stimulation using human chorionic gonadotrophin impairs blastocyst implantation and decidualization by altering ovarian hormone levels and downstream signaling in mice.

Ovarian stimulation induced by follicle-stimulating hormone and human chorionic gonadotrophin (hCG) is commonly used in assisted reproductive technology to increase embryo production. However, recent clinical and animal studies have shown that ovarian stimulation disrupts endometrial function and embryo development and adversely affects pregnancy outcomes. How ovarian stimulation impairs pregnancy establishment and the precise mechanisms by which this stimulation reduces the chances of conception remain unclear. In this study, we first demonstrated that ovarian stimulation using hCG alone impairs implantation, decidualization and fetal development of mice by generating abnormal ovarian hormone levels. We also showed that ovarian hormone levels were altered because of changes in the levels of the enzymes involved in their synthesis in the follicles and corpora lutea. Furthermore, we determined that anomalous ovarian hormone secretion induced by ovarian stimulation alters the spatiotemporal expression of progesterone receptors and their downstream genes, especially in the uterine epithelium. Epithelial estrogenic signaling and cell proliferation were promoted on the day of implantation in stimulated mice and these changes led to the failure of uterine transition from the prereceptive to the receptive state. Collectively, our findings indicate that ovarian stimulation using hCG induces an imbalance in steroid hormone secretion, which causes a failure of the development of uterine receptivity and subsequent implantation and decidualization by altering the expression of steroid receptors and their downstream signaling associated with embryo implantation.

The restorative effects of adipose-derived mesenchymal stem cells on damaged ovarian function.

The clinical application of human adipose-derived mesenchymal stem cells (MSCs) as treatment for intractable diseases or traumatic tissue damage has attracted attention. To address the ability of reactivating injured ovaries, we prepared a rat model with damaged ovaries by using an anticancer agent, cyclophosphamide (CTX). We then investigated the restorative effects on ovarian function and the safety of adipose-derived MSCs (A-MSCs). MSCs were shown to be capable of inducing angiogenesis and restoring the number of ovarian follicles and corpus lutea in ovaries. No deformities, tumor formation or deaths were observed in F1 and F2 rats, indicating that the local injection of MSCs into the ovary did not have any obvious side effects. In addition, the localization of the Y chromosome was investigated using the fluorescent in situ hybridization method by injecting male A-MSCs into the ovaries; as a result, the Y chromosomes were localized not in the follicles, but in the thecal layers. ELISA revealed that A-MSCs secreted higher levels of vascular endothelial cell growth factor (VEGF), insulin-like growth factor-1 (IGF-1) and hepatocyte growth factor (HGF) than tail fibroblast cells. Quantitative real-time PCR and immunohistochemistry showed that higher expression levels of VEGF, IGF-1 and HGF were observed in CTX-treated ovaries after A-MSC transplantation. These findings suggest that MSCs may have a role in restoring damaged ovarian function and could be useful for regenerative medicine.