Advances in the study of DNA damage and repair in mammalian oocytes.

DNA damage is one of the key factors affecting gametogenesis and embryo development. Oocytes are susceptible to DNA damage induced by various endogenous and exogenous factors (e.g., reactive oxygen species, radiation, chemotherapeutic agents, etc.). Current research has revealed that oocytes at various developmental stages are able to respond to various types of DNA damage, repairing DNA or initiating apoptosis through complex mechanisms. Primordial follicular oocytes are more susceptible to apoptosis induced by DNA damage than oocytes entering the growth stage. DNA damage is less likely to induce arrest of the meiotic maturation process in oocytes, however the developmental capacity of oocytes carrying DNA damage is significantly reduced. In clinical practice, aging, radiation and chemotherapy are common causes of oocyte DNA damage, reduced ovarian reserve and infertility in women. Therefore, various methods that can reduce DNA damage and enhance DNA repair in oocytes have been tried in an attempt to protect oocytes. In this review, we systematically summarize the mechanisms of DNA damage and repair in mammalian oocytes at various developmental stages and discuss their potential clinical value with the aim to provide new strategies for fertility protection.