Progesterone administration induces preimplantation embryonic loss in mice

Prenatal progesterone treatment modulates fetal brain transcriptome and impacts adult offspring behavior in mice

Maternal exposure to elevated levels of steroid hormones during pregnancy is associated with the development of chronic conditions in offspring that manifest in adulthood. However, the effects of progesterone (P4) administration during early pregnancy on fetal development and subsequent offspring behavior remain poorly understood. In this study, we aimed to investigate the effects of P4 treatment during early pregnancy on the transcript abundance in the fetal brain and assess the behavioral consequences in the offspring during adolescence and adulthood. Using RNA-seq analysis, we examined the impact of P4 treatment on the fetal brain transcriptome in a dosage-dependent manner. Our results revealed differential regulation of genes involved in neurotransmitter transport, synaptic transmission, and transcriptional regulation. Specifically, we observed bidirectional regulation of transcription factors (TFs) by P4 at different doses, highlighting the critical role of these TFs in neurodevelopment. To assess behavioral outcomes, we conducted open field and elevated plus maze tests. Offspring treated with low-dose P4 (LP4) displayed increased exploratory behavior during both adolescence and adulthood. In contrast, the high-dose P4 (HP4) group exhibited impaired exploration and heightened anxiety-like behaviors compared to the control mice. Moreover, in a novel object recognition test, HP4-treated offspring demonstrated impaired object recognition memory during both developmental stages. Additionally, both LP4 and HP4 groups showed reduced social interaction in the three-chamber test. These results suggest that prenatal exposure to P4 exerts a notable influence on the expression of genes associated with neurodevelopment and may induce alterations in behavioral characteristics in progeny, highlighting the need to monitor progesterone levels during pregnancy for long-term impacts on fetal brain development and behavior.

Embryo Transfer Catheter Contamination With Intravaginal Progesterone Preparations in a Simulated Embryo Transfer Model Impairs Mouse Embryo Development: Are There Implications for Human Embryo Transfer Technique?

OBJECTIVES

To study the effect of embryo transfer (ET) catheter contact with intravaginal progesterone preparations on mouse embryo development.

STUDY DESIGN

In a simulated ET model, ET catheters were loaded with culture medium, placed in contact with intravaginal progesterone gel (Crinone 8%) or micronized progesterone intravaginal inserts (Endometrin 100 mg), and the intracatheter culture medium flushed. Embryos were cultured in the flushed culture medium at variable dilutions for variable lengths of time. Proportion of embryos progressing to blastocyst, embryo cell number, and apoptotic index was analyzed.

RESULTS

None of the embryos cultured in undiluted progesterone-exposed medium progressed to blastocyst. The likelihood of achieving blastocyst status and the average embryo cell number increased significantly as culture media exposed to intravaginal progesterone was diluted. A significant decrease in cell number became apparent between 1 and 2 hours of exposure. Interestingly, the apoptotic index was significantly higher in progesterone-exposed embryos as compared to unexposed embryos.

CONCLUSION

The contamination of ET catheter with intravaginal progesterone significantly impairs mouse embryo development, likely due in part to increased programmed cell death.

Sustained-release progesterone nanosuspension following intramuscular injection in ovariectomized rats

The production of an intramuscular (IM) injection of natural progesterone would provide a safer solution than using semi synthetic progesterone. However, disadvantages such as low solubility and a short half life prevent the use of natural progesterone. In this study, we formulated a sustained release form of natural progesterone to be given as IM injection. A progesterone nanosuspension (PNS) was first developed and then dispersed in a thermosensitive gel matrix. The selected nanoparticles showed an average particle size of 267 nm and a zeta potential approaching-41 mV. The in vitro release profile of PNS from the F127 plus methyl cellulose gel followed zero order kinetics and correlated linearly with the weight percentage of gel dissolved, demonstrating that the overall rate of release of PNS is controlled by dissolution of the pluronic F127/methyl cellulose (MC) gel (r² > 0.99). The pharmacokinetic parameters of the PNS (6 mg/mL) in pluronic F127/MC gel were evaluated in comparison with the control progesterone suspension. After the administration of PNS in F127/MC gel into the rats, a maximum serum concentration of 22.1 ± 1.9 ng/mL was reached at a T_max of 4.05 ± 0.1 h. The terminal half life was 12.7 ± 0.8 h. The area under the curve AUC_0-∞ of the injected formula was 452.75 ± 42.8 ng·h/mL and the total mean residence time was 18.57 ± 1.44 h. The PNS in gel was significantly different from the control in rate and extent at P < 0.001. The natural progesterone which was nanosized and formulated in a thermosensitive gel significantly sustained the action of natural progesterone so that it could be injected every 36 h instead of every day. Moreover, this formula is expected to provide a much safer choice than the use of semi-synthetic progesterone.