Effects of androgen on embryo implantation in the mouse delayed-implantation model

ObjectiveTo examine the effects of androgen on implantation and decidualization in the mouse delayed-implantation model.DesignExperimental animal study.SettingUniversity research laboratory.Animal(s)Sexually mature female mice (Kunming White strain).Intervention(s)Delayed and activated implantation; pseudopregnancy; embryo transfer (ET); E2 assay; inhibitor.Main Outcome Measure(s)Effects of androgen on embryo implantation were determined by treating the mice under delayed implantation with different doses of testosterone propionate (TP); the effects of androgen on the expression of implantation-related genes were examined by in situ hybridization.Result(s)Delayed implantation could be initiated by TP. Dihydrotestosterone was also able to initiate implantation in the delayed-implantation model. The implantation window could be maintained for at least 48 hours by 5 mg TP per mouse. Prostaglandin endoperoxide synthase 2 (Ptgs2) and microsomal prostaglandin E synthase (mPtges) were aberrantly expressed in mouse uterus at implantation sites after delayed implantation was activated by high doses of TP.Conclusion(s)A low dose of TP led to a delay in embryo implantation, but a high dose caused aberrant expression of both Ptgs2 and mPtges at the implantation site. It is possible that high doses of TP may disturb peri-implantation development or may be involved in early pregnancy loss by disturbing the uterine prostaglandin system.