Molecular evidence that follicle development is accelerated compared to .

In this study, we systematically compared the morphological, functional and molecular characteristics of granulosa cells and oocytes obtained by a three-dimensional model of ovine ovarian follicular growth with those of follicles recovered Preantral follicles of 200 µm diameter were recovered and cultured up to 950 µm over a 20-day period. Compared with follicles, the culture conditions maintained follicle survival, with no difference in the rate of atresia. However, the conditions induced a slight decrease in oocyte growth rate, delayed antrum formation and increased granulosa cell proliferation rate, accompanied by an increase and decrease in and mRNA expression respectively. These changes were associated with advanced granulosa cell differentiation in early antral follicles larger than 400 µm diameter, regardless of the presence or absence of FSH, as indicated by an increase in estradiol secretion, together with decreased AMH secretion and expression, as well as increased expression of , , , , , , , and There was a decrease in the expression of oocyte-specific molecular markers , , , and compared to that Moreover, a higher percentage of the oocytes recovered from cultured follicles 550 to 950 µm in diameter was able to reach the metaphase II meiosis stage. Overall, this model of ovarian follicle development is characterized by accelerated follicular maturation, associated with improved developmental competence of the oocyte, compared to follicles recovered .