237 EFFECT OF A PTEN INHIBITOR ON OVARIAN CONTENTS OF APOPTOSIS-RELATED PROTEINS AND ANTI-MÜLLERIAN HORMONE (AMH) IN A/J MICE

Abstract

Strain/individual differences in superovulation efficiency with gonadotropins constitute a serious problem in mouse reproduction (Suzuki et al. 1996 Reprod. Fertil. Dev. 8, 975–980). Because PI3K/Akt signalling pathway is involved in ovarian folliculogenesis and phosphatase and tensin homologue deleted from chromosome 10 (PTEN) negatively regulates the process, I have been studying the effect of PTEN inhibitors on ovarian folliculogenesis and ovulation in mice to improve superovulation efficiency. In the present study, I compared ovarian contents of apoptosis-related proteins and anti-Müllerian hormone (AMH, an activity/number indicator of preantral and early-antral follicles) in A/J mice to examine the possibilities of an exogenous PTEN inhibitor to suppress follicular atresia and to promote folliculogenesis. At PMSG injections, 0 (control, n = 5) or 2 mg kg^–1 B.W. (treated, n = 5) of a PTEN inhibitor, dipotassium bisperoxo (picolinato) oxovanadate (V), dissolved in Ringer solution were also injected to 28-day-old A/J female mice. Ovaries were collected 24 h after the injections. Ovarian protein contents of six proteins (shown in results) were measured by quantitative Western blots with β-actin as an internal control using whole ovary homogenates. Quantitativity of the Western blots were confirmed by calibration curves produced using a dilution series of sample mix (see Suzuki et al. 2011 Exp. Anim. 60, 193–196, for method details). Observed values were compared between control and treated groups by ANOVA. No significant difference in ovarian protein contents of apoptosis-related proteins (cleaved caspase-3, cleaved caspase-9, cleaved PARP, BAX, and BCL-2) was found between the 2 groups (P = 0.951, 0.548, 0.095, 0.226, and 0.363, respectively; n = 5). On the other hand, ovarian AMH protein was more abundant in the treated group than that in the control group (P = 0.009). Although these results should be confirmed by more precise quantification methods such ELISA or RIA to eliminate possible lack of difference in apoptosis-related proteins due to methodology, they suggest that PTEN inhibitors can promote ovarian folliculogenesis but not suppress follicular atresia.

This work was supported by a grant from the Ministry of Health, Labour and Welfare of Japan.