Apoptosis in the ovary and follicular atresia

Background: In the ovary, growing follicles develop from a pool of primordial follicles constituted early in life. The majority of ovarian follicles undergo atresia. Follicular atresia is an important and negative process during the development of ovarian follicles. Cell apoptosis is believed to be involved in this process. This article is an overview of some researches on apoptosis in the ovaries and the factors involved in it. Materials and Methods: In this review article, the PubMed, Scopus, Embase, Current Content, and IranMedex databases were searched using keywords such as "apoptosis" and "ovary". The full-text articles published between 1997 and 2017 in English or Persian were included in the study. The genes involved in ovarian apoptosis and factors controlling follicle atresia and their role in ovarian follicular reserve and fertility were investigated. Results: Although follicular atresia occurs at all stages of follicular development, it has been shown that this process is dependent on the developmental stage and a large part of it is observed in the transitional stage between the preantral follicles and the antrum formation. Different paracrine and autocrine factors control the cell death of the ovary. Conclusion: Ovarian cells receive conflicting signals for survival and death, and it seems that the reason for determining the fate of cells in different stages of follicular development is the interaction between different signals.