In vitro oogenesis and parthenogenetic development of chicken female germ cells

In vitro reconstruction of gametogenesis is an important research direction in germ cell biology and assisted reproduction. While substantial progress has been made in the in vitro oogenesis of mammalian germ cells, analogous approaches in avian species remain unexplored. In this study, we investigated the capacity of chicken primordial germ cells (PGCs) and oogonial stem cells (OSCs) to differentiate into oocyte-like cells in vitro. Under meiotic induction with retinoic acid and vitamin C, both PGCs and OSCs initiated meiosis but arrested at the prophase I stage. Subsequent exposure to follicle-stimulating hormone, human chorionic gonadotropin, and progesterone facilitated the resumption of meiosis, leading to the formation of secondary oocytes. Next, parthenogenetic activation experiments showed that these germ cell-derived secondary oocytes were capable of undergoing cleavage and developing into blastomeres. Furthermore, in the aged and stopped-laying ovaries, OSCs retained the proliferation ability but lost their differentiation potential to increase the risk of germ cell tumor. The current in vitro oogenesis system enabled evaluation of healthy and compromised oocytes in avian species. This study not only provides direct evidence for the in vitro recapitulation of oogenesis in birds but also offers new avenues for preserving female germ cells and mass production of chicken oocytes.