Progesterone and estradiol regulate sperm hyperactivation and in vitro fertilization success in mice

Abstract

Progesterone (P) and 17β-estradiol (Eβ) form the well-known hormone pair that regulates sperm capacitation. Here, we examined the regulatory effects of P and Eβ on sperm hyperactivation in mice and evaluated the in vitro fertilization (IVF) success. Although P enhanced hyperactivation, Eβ dose-dependently suppressed the P-enhanced hyperactivation. Moreover, P increased IVF success, whereas Eβ suppressed the P-induced increase in IVF success in a dose-dependent manner. Thus, P and Eβ competitively regulate hyperactivation and IVF success in mice. Since P and Eβ concentrations generally change during the estrous cycle, sperm are speculated to capacitate in response to the oviductal environment and fertilize the oocyte.

Keywords: Estradiol; Hyperactivation; In vitro fertilization; Progesterone; Sperm.

Fig. 1.

Suppression of progesterone-enhanced hyperactivation by 17β-estradiol. The motility (A) and hyperactivation (B) percentages of sperm exposed to 20 ng/ml of progesterone (P) after exposure to different 17β-estradiol (Eβ) concentrations are shown. The motility (C) and hyperactivation (D) percentages of sperm exposed simultaneously to 20 ng/ml of P and different Eβ concentrations are shown. The motility (E) and hyperactivation (F) percentages of spermatozoa exposed to 20 ng/ml of P before exposure to different Eβ concentrations are shown. Each experiment was repeated four times using one mouse each time. Data represent the mean ± standard deviation. Vehicle, a medium with 0.2% ethanol; 20 ng/ml P, a medium with 20 ng/ml of P and the vehicle; different Eβ concentrations + 20 ng/ml P, mediums with different Eβ concentrations, 20 ng/ml of P, and the vehicle. * Significant difference compared with “vehicle” (P < 0.05). ^# Significant difference compared with “20 ng/ml P” (P < 0.05).

Fig. 2.

Effects of an estradiol isoform on the increase of hyperactivation and in vitro fertilization success caused by progesterone. The motility (A) and hyperactivation (B) percentages of sperm exposed to 20 ng/ml of progesterone (P) after exposure to different 17α-estradiol (Eα) concentrations are shown. Each experiment was repeated four times using one mouse each time. (C) The percentages of two-cell embryos when in vitro fertilization (IVF) was performed with or without 20 ng/ml of P and 20 ng/ml of Eα are shown. IVF experiments were performed four times using one female and one male mouse each time. Data represent the mean ± standard deviation. For (A) and (B): Vehicle, a medium with 0.2% ethanol; 20 ng/ml P, a medium with 20 ng/ml of P and the vehicle; 20 ng/ml Eα + 20 ng/ml P, a medium with 20 ng/ml of Eα, 20 ng/ml of P, and the vehicle; 2 ng/ml Eα + 20 ng/ml P, a medium with 2 ng/ml of Eα, 20 ng/ml of P, and the vehicle; 200 pg/ml Eα + 20 ng/ml P, a medium with 200 pg/ml of Eα, 20 ng/ml of P, and the vehicle. * Significant difference compared with “vehicle” (P < 0.05). For (C): Vehicle, a medium with 0.2% ethanol; P, a medium with 20 ng/ml of P and the vehicle; Eα, a medium with 20 ng/ml of Eα and the vehicle; P + Eα, a medium with 20 ng/ml of P, 20 ng/ml of Eα, and the vehicle. * Significant difference compared with “vehicle” and “Eα” (P < 0.05).

Fig. 3.

Membrane estrogen receptor involvement in suppressing progesterone effects on hyperactivation and in vitro fertilization. The motility (A) and hyperactivation (B) percentages when sperm were cultured with or without 20 ng/ml of progesterone (P), 20 ng/ml of 17β-estradiol (Eβ) or 1 μM of tamoxifen (tamo) are shown. After sperm were exposed to the vehicle or 1 μM of tamo, they were exposed to the vehicle or 20 ng/ml of Eβ. After the abovementioned exposures, sperm were exposed to 20 ng/ml of P. Each experiment was repeated four times using one mouse each time. (C) The percentages of two-cell embryos when in vitro fertilization (IVF) was performed with or without 20 ng/ml of P, 20 ng/ml of Eβ, or 1 μM of tamo are shown. IVF experiments were performed four times using one female and one male mouse each time. Data represent the mean ± standard deviation. For (A) and (B): Vehicle, a medium with 0.2% ethanol and 0.1% dimethyl sulfoxide (DMSO); P, a medium with 20 ng/ml of P and the vehicle; P + Eβ, medium with 20 ng/ml of P, 20 ng/ml of Eβ, and the vehicle; P + Eβ + tamo, a medium with 20 ng/ml of P, 20 ng/ml of Eβ, 1 μM of tamo, and the vehicle. * Significant difference compared with “vehicle” and “P + Eβ” (P < 0.05). For (C): Vehicle, a medium with 0.2% ethanol and 0.1% DMSO; P, a medium with 20 ng/ml of P and the vehicle; Eβ, a medium with 20 ng/ml of Eβ and the vehicle; P + Eβ, a medium with 20 ng/ml of P, 20 ng/ml of Eβ, and the vehicle; tamo, a medium with 1 μM of tamo and the vehicle; P + Eβ + tamo, a medium with 20 ng/ml of P, 20 ng/ml of Eβ, 1 μM of tamo, and the vehicle. * Significant difference compared with “vehicle”, “Eβ”, “P + Eβ”, and “tamo” (P < 0.05).

Fig. 4.

Motility (A) and hyperactivation (B) percentages when sperm were exposed to 20 ng/ml of P after exposure to different BSA-Eβ concentrations are shown. Motility (C) and hyperactivation (D) percentages, when sperm were cultured with or without 20 ng/ml of P, 7.4 nM of BSA-Eβ, or 1 μM of tamo, are shown. After sperm were exposed to the vehicle or 1 μM of tamo, they were exposed to the vehicle or 7.4 nM of BSA-Eβ. After the abovementioned exposures, sperm were exposed to 20 ng/ml of P. Each experiment was repeated four times using one mouse each time. Data represent the mean ± standard deviation. For (A) and (B): Vehicle, a medium with 0.1% pure water and 0.1% ethanol as the vehicle; P, a medium with 20 ng/ml of P and the vehicle; 7.4 nM BSA-Eβ + P, a medium with 20 ng/ml of P, 7.4 nM of BSA-Eβ, and the vehicle; 740 pM BSA-Eβ + P, a medium with 20 ng/ml of P, 740 pM of BSA-Eβ, and the vehicle; 74 pM BSA-Eβ + P, a medium with 20 ng/ml of P, 74 pM of BSA-Eβ, and the vehicle. * Significant difference compared with “vehicle”, “7.4 nM BSA-Eβ + P”, “740 pM BSA-Eβ + P”, and “74 pM BSA-Eβ + P” (P < 0.05). For (C) and (D): Vehicle, a medium with 0.1% pure water, 0.1% ethanol, and 0.1% dimethyl sulfoxide as the vehicle; P, a medium with 20 ng/ml of P and the vehicle; P + BSA-Eβ, a medium with 20 ng/ml of P, 7.4 nM of BSA-Eβ, and the vehicle; P + BSA-Eβ + tamo, a medium with 20 ng/ml of P, 7.4 nM of BSA-Eβ, 1 μM of tamo, and the vehicle. * Significant difference compared with “vehicle” and “P + BSA-Eβ” (P < 0.05).