In vitro growth and development of bovine oocyte-granulosa cell complexes on the flat substratum: effects of high polyvinylpyrrolidone concentration in culture medium.

The aim of this study was to establish a culture system to support the growth of bovine oocytes as enclosed in granulosa cell complexes that extend on a flat substratum. Such systems have been established for mouse oocytes but are not applicable to larger animals because it is difficult to maintain an appropriate association between the oocyte and companion somatic cells. Growing bovine oocytes with a mean diameter of 95 microm were isolated from early antral follicles: the growing stage corresponds to that of oocytes in preantral follicles of 12-day-old mice.

Growth, antrum formation, and estradiol production of bovine preantral follicles cultured in a serum-free medium.

The objective of this study was to identify factors that would allow the establishment of a serum-free culture system that could support follicular and oocyte growth, antrum formation, and estradiol-17beta (E(2)) production in preantral follicles of bovine ovaries. Large preantral follicles (145-170 micro m in diameter) were microsurgically dissected from ovaries, embedded in 0.15% type I collagen gels, and maintained in a serum-free medium for up to 13 days at 38.