1.Characterization of ovarian responses to equine chorionic gonadotropin of aromatase-deficient mice with or without 17β-estradiol supplementation.
Toda K1, Hayashi Y2, Ono M3, Saibara T3. Endocrinology. 2016 Feb 26:en20151701. [Epub ahead of print]
Aromatase is an enzyme catalyzing the final step of 17β-estradiol (E2) biosynthesis. Aromatase-deficient (ArKO) mice displayed vital roles of E2 at various tissue-sites, including ovary. Here, we report attenuated responses of ArKO ovary to equine chorionic gonadotropin (eCG), an alternative to FSH. Ovarian contents of cAMP and anti-Müllerian hormone (AMH), putative factors reducing sensitivity to gonadotropins, were significantly elevated in ArKO mice compared with those in WT mice in the basal state. Accordingly, eCG-induced ovarian alterations in cAMP contents, phosphorylation levels of signaling molecules and mRNA expression of eCG-targeted genes were blunted in ArKO mice compared with those in WT mice. Treatment of ArKO mice with E2 decreased ovarian cAMP and AMH contents to the WT levels, but did not restore the sensitivity. Microarray analysis coupled with quantitative RT-PCR analysis identified seven genes of which the mRNA expression levels in ArKO ovaries were significantly different from those in the WT ovaries in the basal state, and were not normalized by E2 supplementation, indicating possible involvement of these gene products in the determination of ovarian sensitivity to eCG.
2.Maturation promoting factor destabilization facilitates postovulatory aging-mediated abortive spontaneous egg activation in rat.
Prasad S1, Koch B2, Chaube SK1. Dev Growth Differ. 2016 Apr;58(3):293-302. doi: 10.1111/dgd.12272. Epub 2016 Mar 17.
The present study was designed to investigate whether destabilization of maturation promoting factor (MPF) leads to postovulatory aging-mediated abortive spontaneous egg activation (SEA). If so, we wished to determine whether changes in Wee-1 as well as Emi2 levels are associated with MPF destabilization during postovulatory aging-mediated abortive SEA in rats eggs aged in vivo. For this purpose, sexually immature female rats were given a single injection (20 IU IM) of pregnant mare serum gonadotropin for 48 h followed by single injection of human chorionic gonadotropin (20 IU). Ovulated eggs were collected after 14, 17, 19 and 21 h post-hCG surge to induce postovulatory aging in vivo. The morphological changes, Wee1, phosphorylation status of cyclin dependent kinase 1(Cdk1), early mitotic inhibitor 2 (Emi2), anaphase promoting complex/cyclosome (APC/C), cyclin B1, mitotic arrest deficient protein (MAD2) levels and Cdk1 activity were analyzed.
3.A simple method for inducing estrous cycle stage-specific morphological changes in the vaginal epithelium of immature female mice.
Merkwitz C1, Blaschuk O2, Eplinius F1, Winkler J3, Prömel S3, Schulz A4, Ricken A5. Lab Anim. 2015 Nov 13. pii: 0023677215617387. [Epub ahead of print]
The vaginal epithelium of the adult female laboratory rodent changes from mucous secretion to cornification over the course of the estrous cycle. The morphophysiological changes occur with such regularity, accuracy and precision that the specific stage of the estrous cycle in the rat can be determined by inspection of the vaginal opening and/or exfoliative vaginal cytology. However, in the mouse, post-mortem vaginal histology is often required to determine the estrous cycle stage for ensuring the required level of reliability. Consequently, an excess number of female adult mice are needed to allow for the delivery of sufficient numbers of mice in a desired estrous cycle stage. In this study, we demonstrate that the standard procedure for oocyte superovulation and collection in the laboratory mouse (e.g. injection of equine chorionic gonadotropin followed 48 h later by human chorionic gonadotropin) can also be reliably used to induce changes in the epithelium of 3.
4.Tumor necrosis factor alpha inhibits ovulation and induces granulosa cell death in rat ovaries.
Yamamoto Y1, Kuwahara A1, Taniguchi Y1, Yamasaki M1, Tanaka Y1, Mukai Y1, Yamashita M1, Matsuzaki T1, Yasui T1, Irahara M1. Reprod Med Biol. 2015;14(3):107-115. Epub 2014 Dec 13.
PURPOSE: We evaluated the role of tumor necrosis factor alpha (TNFα) in rat ovulation and granulosa cell death of ovarian follicles during the periovulatory stage.