Attempt to Enhance Superovulation Efficiency in Mice with a PTEN Inhibitor

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 515-547-Female Reproductive Endocrinology
Basic/Translational
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-524
Osamu Suzuki*
Natl Inst of Biomed Innovation, Ibaraki, Japan
[Aim] Strain/individual differences in superovulation efficiency with gonadotropins constitute a serious problem in mouse reproduction (Ref 1). Gonadotropins stimulate the maturation of developing ovarian follicles, but not primordial follicle activation, which is regulated by the PI3K pathway. Activation is negatively controlled by the Phosphatase and Tensin Homolog Deleted from Chromosome 10 (PTEN). Injection of a PTEN inhibitor might enhance primordial follicle activation in vivo by suppressing PTEN. Therefore, we tested whether injection of a PTEN inhibitor followed by gonadotropin injections increases the number of ovulated oocytes. [Method] We used the low responder A/J mouse strain (Ref. 1). In Experiment 1, we injected females with 0, 3, 30, or 300 µg of dipotassium bisperoxo(picolinato)oxovanadate (V) (bpV(pic), Enzo) on Day 0. We recorded the ovary weight/body weight ratio (OBR) on Days 1 to 4. The amount of ovarian anti-Müllerian hormone (AMH) was measured by quantitative Western blots with GAPDH as an internal control (Ref. 2). In Experiment 2, we examined the number of ovulated oocytes with four combinations of bpV(pic) dose and intervals from the bpV(pic) to PMSG injections: 1) 3 µg and PMSG on Day 3, 2) 3 µg and PMSG on Day 4, 3) 30 µg and PMSG on Day 1, and 4) 30 µg and PMSG on Day 2. Ovulation was induced by PMSG and hCG. [Results and Discussion] In Experiment 1, two of eleven mice (18%) given 300 µg of bpV(pic) died the next day, indicating that 300 µg was excessive. No mice died with 30 or 3 µg. In the control group (0 µg), OBR decreased each day. By contrast, OBR peaked on Day 2 with 30 µg and on Day 3 with 3 µg. The amount of ovarian AMH proteins showed a tendency similar to BOR. In Experiment 2, the average number of oocytes collected was 1) 17.20±0.66 vs. 9.40±1.63 (control vs. bpV(pic), mean±SEM, n=5), 2) 7.80±0.66 vs. 9.00±1.45, 3) 9.8±1.59 vs. 11.2±1.02, and 4) 9.40±1.03 vs. 7.40±1.91. No significant difference was found on analysis of variance, but more oocytes tended to be collected in the bpV(pic) groups in experimental groups 1–3. Our new method using both PTEN inhibitors and gonadotropins is a promising method for improving superovulation, although it still needs work.

(1) Suzuki et al. (1996) Reprod Fertil Dev, 8(6):975-980. (2) Suzuki et al. (2011) Exp Anim, 60(2):193-196.

Nothing to Disclose: OS

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This work was supported by a grant from the Ministry of Health, Labor, and Welfare of Japan.