Gene Expression in Mouse Ovarian Follicle Development In Vivo versus an Ex Vivo Alginate Culture System

摘要

Ovarian follicle maturation results from a complex interplay of endocrine, paracrine, and direct cell-cell interactions. This study compared the dynamic expression of key developmental genes during folliculogenesis in vivo and during in vitro culture in a three-dimensional alginate hydrogel system. Candidate gene expression profiles were measured within mouse two-layered secondary follicles (2LS), multi-layered secondary follicles (MLS), and cumulus-oocyte complexes (COCs). The expression of 20 genes involved in endocrine communication, growth signaling, and oocyte development was investigated by real-time PCR. Gene product levels were compared between i) follicles of similar stage and ii) COCs derived either in vivo or by in vitro culture. For follicles cultured for 4 days, the expression pattern and the expression level of 12 genes was the same in vivo and in vitro. Some endocrine (Cyp19a1, Inhβa) and growth related genes (Bmp15, Kitl, Tgfβr2) were down-regulated relative to in vivo follicles. For COCs obtained from cultured follicles, endocrine related genes (Inhα and Inhβa) had increased expression relative to in vivo counterparts, whereas growth related genes (Bmp15, Gdf9, Kit) and zona pellucida genes were decreased. However, most of the oocyte specific genes (e.g., Figlα, Jag1, Mater) were expressed in vitro at the same level and with the same pattern as in vivo-derived follicles. These studies establish the similarities and differences between in vivo and in vitro cultured follicles, guiding the creation of environments that maximize follicle development and oocyte quality.