Effects of alginate hydrogels on in vitro maturation outcome of mouse preantral follicles

Abstract

Ovarian follicle growth and oocyte maturation require communications between the oocyte and its surrounding somatic cells. Three-dimensional structures provide cell culture conditions that increase interactions between the cellular components when compared to 2-dimensional structures. In this study, alginate matrices were employed to maintain a 3-dimensional architecture to examine its effects on in vitro culture outcomes using mouse ovarian follicles. Ovaries were obtained from the 14-day-old C57BL/6 mice, and preantral follicles were isolated and cultured in either a 2-dimensional culture system or 0.125/0.25% alginate matrices-based 3-dimensional culture systems. We successfully observed encapsulation within 0.125 and 0.25% alginate matrices, which maintained the follicular spherical architecture, with a centrally placed oocyte and layers of granulosa cells. All culture outcomes were comparable between the 2-dimensional control and 3-dimensional alginate group. However, 0.25% alginate hydrogels led the lower rates of follicle survival and antral formation in comparison to the 2-dimensional control and 0.125% alginate. These results demonstrate that a non-permissive stiffness from the high concentration of alginate could interfere with cell-to-cell communication of oocytes and follicles. The extracellular matrix interacts with the oocyte and granulosa cells, resulting in direct effects on their proliferation. The development of a 3-dimensional culture system can enhance follicle maturation and produce meiotically-competent oocytes to provide advanced reproductive options for IVF patients in the future.