Secretion profiles from in vitro cultured follicles, isolated from fresh prepubertal and adult mouse ovaries or frozen–thawed prepubertal mouse ovaries

Abstract

In vitro folliculogenesis could be a new technology to produce mature oocytes from immature follicles that have been isolated from cryopreserved or fresh ovarian tissue. This technique could also be a tool for evaluation of oocyte quality and/or for determination of follicular parameters during follicular growth. Our objective was to characterize in mice the secretion profiles of follicles that had been isolated mechanically during in vitro follicular growth and in relation to the growth curve. Early preantral follicles from fresh prepubertal and adult mouse ovaries or frozen-thawed prepubertal mouse ovaries were cultured individually in microdrops under oil for 12 days. Each day, two perpendicular diameters of the follicles were measured. From day-3 to day-12 of culture, culture medium was collected and preserved for determination of inhibin B, anti-Müllerian hormone (AMH) and estradiol levels. At the end of the culture, after maturation, the status of the oocyte was evaluated. Follicular growth and their individual hormone production did not always correlate. Inhibin B was never secreted from follicles of less than 200 μm diameter, whether the follicles were examined when fresh or after freezing-thawing. Estradiol secretion was never observed in frozen-thawed follicles. AMH was mainly secreted between day-3 and day-9. Despite similar morphological aspects at the start of culture, follicles selected for in vitro folliculogenesis were found to be heterogeneous and differed in their ability to grow and to produce hormones, even if they had similar growth curves. Follicles from frozen-thawed ovaries developed slowly and produced fewer hormones than freshly collected follicles.

Protein profile of mouse ovarian follicles grown in vitro

“…This could be an indicator of steroidogenesis activity increasing in developing follicles. These results are consistent with estradiol secretion studies in ovarian follicles in culture, which associated secretion with cellular proliferation, describing a stabilization or decrease of estradiol secretion associated with a reduction in granulosa-cell proliferation ( Boland et al , 1993 ; Liu et al , 2002 ; Dorphin et al , 2012 ).…”

Anti-Müllerian hormone reduces growth rate without altering follicular survival in isolated caprine preantral follicles cultured in vitro

“…However, steroid secretion (E2, P4 and T), as well as overall mRNA expression for key steroidogenic enzymes, was not affected by the culture conditions. This may be due to the large individual variation in steroid production among follicles (Dorphin et al 2012). To our knowledge, there are no studies reporting the effects of AMH on steroid production of isolated preantral follicles.…”