Role of programmed cell death in mammalian ovarian follicular atresia

Programmed cell death (PCD) is a fundamental process in the development process of organisms, including apoptosis, autophagy, ferroptosis, and pyroptosis. In mammalian ovaries, 99 % of follicles undergo atresia, while only 1 % mature and ovulate, which limits the reproductive efficiency of mammals. The PCD process is closely related to the regulation of follicle development and atresia. Recently, an increasing number of studies have reported that autophagy, pyroptosis, and ferroptosis of PCD are involved in regulating granulosa cell apoptosis and follicular atresia. Granulosa cell apoptosis is a hallmark of follicular atresia. Therefore, an understanding of molecular mechanisms regulating PCD events is required for future advances in the diagnosis and management of various disorders of follicular atresia. This review summarizes recent work on apoptosis, autophagy, pyroptosis, and ferroptosis of PCD that affect granulosa cell survival and follicular atresia, and further elucidating the mechanisms of follicular atresia and providing new directions for improving the reproductive capacity of humans and animals.