Follicular atresia in the prepubertal spiny mouse (Acomys cahirinus) ovary.

This study was designed to determine follicular atresia in the newborn and the prepubertal spiny mouse. We analyzed the processes of follicle loss using classical markers of apoptosis (TUNEL reaction, active caspase-3) and autophagy (Lamp1). Numerous small clear vacuoles and autophagosomes as well as strong Lamp1 staining were observed in dying oocytes of all follicle types, especially of the primordial and primary ones. Active caspase 3 and the TUNEL reaction were detected only in the granulosa cells of large secondary and antral follicles. The expression of apoptosis and autophagy markers was also changing during the prepubertal period. Western blot analysis indicated that at the moment of birth, females undergo an increased rate of follicular atresia mediated by autophagy, while apoptosis is the dominant form of ovarian atresia in consecutive postnatal days. On the basis of these observations, we concluded that apoptosis and autophagy are involved in follicular atresia and these processes are cell and developmental stage-specific.