BACKGROUND Neovascularization is necessary for follicular growth. Vascularization is first observed in preantral follicles, and thereafter the vasculature markedly increases in follicles undergoing development. Neovascularization includes angiogenesis and vasculogenesis. Vasculogenesis is the formation of new blood vessels by bone marrow-derived endothelial progenitor cells. It is unclear wheth...

BACKGROUND One of the most major obstacles of ovarian tissue vitrification is suboptimal developmental competence of follicles. Matrix metalloproteinases 2 (MMP-2) and 9 (MMP-9) and their tissue inhibitors TIMP-1 and TIMP-2 are involved in the remodeling of the extracellular matrix in the ovaries. OBJECTIVE This study aimed to evaluate the expression of MMP-2, MMP-9, TIMP-1, and TIMP-2 genes ...

Mammalian oocytes grow within ovarian follicles in which the oocyte is coupled to surrounding granulosa cells by gap junctions. We report here that growing oocytes isolated from mouse preantral follicles are incapable of recovering from an experimentally induced acidosis, and that oocytes acquire the ability to manage acid loads by activating Na(+)/H(+) exchange during growth. By contrast, gran...

Anti-Müllerian hormone (AMH) plays an important role in folliculogenesis. AMH null mice display an increased recruitment of primordial follicles. Nevertheless, these mice do not have proportionally more preovulatory follicles. Therefore, AMH null mice provide an interesting genetic model to study the regulation of species-specific number of preovulatory follicles. We studied the follicle pool t...

This study evaluated the levels of c-kit mRNA in goat follicles and the effects of kit ligand (KL) on the in vitro development of cultured preantral follicles. Preantral follicles isolated from goat ovarian cortex were cultured for 18 days in α-MEM(+) supplemented with KL (0, 50 or 100 ng/mL) in the absence or presence of follicle stimulating hormone (FSH). Real-time PCR showed that c-kit mRNA ...

Information on the ovarian follicle reserve in the African elephant (Loxodonta africana) is lacking. This study set out to determine the ratios of early preantral follicles and their relative dimensions in the ovaries of 16 African elephant aged 10-34 years. The ovaries were sectioned histologically. Follicles were counted and classified according to expansion of the pre-granulosa cells. Early ...

The majority of thousands of oocytes in the ovaries are small, non-growing and reside in preantral follicles (PFs). The development of a culture system for preantral follicle may be very useful for understanding the complex mechanism in folliculogenesis at early stages of development as wells as could offer a significant way for the propagation of livestock, including goats. The in vitro follic...

The processes that precisely control the selection of ovulatory follicles from a growing cohort are poorly understood. This reduction in follicle number occurs through several phases of selection, consequently we limit the use of the term 'selection' to the first major reduction of growing follicles, at the pre- to early antral stage. The final process of selection, achieving the appropriate ov...

Growth and development of ovarian follicles require a series of coordinated events that induce morphological and functional changes within the follicle, leading to cell differentiation and oocyte development. The preantral early antral follicle transition is the stage of follicular development during which gonadotropin dependence is obtained and the progression into growing or atresia of the fo...

Objectives: It was aimed to investigate the effects of different doses of follicle stimulating hormone (FSH) and activin A on the growth and maturation of preantral mouse follicles during the in vitro culture. Methods: Preantral follicles (90-100 µm in diameter) were harvested from 6-8 week-old Syrian mice and cultured in TCM199 culture medium for 6 days to see the effect of FSH and Activin A...