Ultrastructural, Histological, and Immunofluorescence Evaluation of Autophagy in Murine Embryonic, Postnatal, and Prepubertal Ovaries

ABSTRACT

The ovary of mammals is a unique organ that is characterized by morphological tissue rearrangements, which include the development and death of germ cells, alongside the development and atresia of follicles. Additionally, the initiation of meiosis in germ cells, the development of follicles, and the onset of puberty likely involve cellular mechanisms such as autophagy. Despite some knowledge has been gained, there remains a gap in understanding the precise role of autophagy in these processes, particularly with the emergence of a specific variant termed mitophagy in reproductive sciences. In addition to its role in regulating energy metabolism and maintaining cellular homeostasis, autophagy can either facilitate cell survival or induce cell death. Considering the critical time points during female gonad development where autophagy may be involved in various cellular processes, we assessed the ultrastructural and histological characteristics of autophagy. This evaluation included Beclin‐1 immunodetection as an autophagy marker in the embryonic ovary of female mice at 13.5 days post coitum, as well as in ovaries collected from newborns at 1 postnatal day and prepubertal at 21 postnatal days. The study revealed ultrastructural features of autophagy and mitophagy in embryonic and neonatal germ cells, as well as in follicular development and atresia in the ovaries of prepubertal mice. This process was confirmed by the detection of Beclin‐1 protein expression. Moreover, our findings indicate a heightened level of Beclin‐1 immunodetection in the oocytes of preantral and antral atretic follicles, which was correlated with the progress of atresia.