In Vitro Growth and Development of Mouse Preantral Follicles

The mammalian ovary has a large number of primordial and preantral follicles, which are a potential source of oocytes for the in vitro mass production of embryos. Several in vitro culture systems have been developed to support the growth and development of oocytes from mouse preantral follicles. Under the appropriate condition, meiotically incompetent oocytes from preantral follicles can grow to final size and complete nuclear maturation in vitro. Furthermore, the successful production of live young from in vitro grown and matured oocytes demonstrates that oocytes from preantral follicles are able to acquire full developmental capacity in vitro. However, the efficiency of in vitro production of embryos from mouse preantral follicles is still low. In farm animals as well as human, the growth of oocyte from preantral follicle to the meiotic competence stage has yet to be demonstrate. Therefore, further studies to improve the culture condition or to develope new culture system should be needed in the future. In addition, the visible progress in the establishment of the in vitro culture system for preantral follicles of farm animals and human could help to enlarge the populations of valuable agricultural, phamaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that jeopardize oocytes.