Mitophagy is the process by which cells selectively remove supernumerary or damaged mitochondria through autophagy, and is crucial for mitochondrial homeostasis and cell survival. Mitochondria play vital roles in determining the developmental competence of oocytes. During the early stages of oogenesis, aberrant mitochondria can be removed by mitophagy. After oocyte formation, mitophagy is not actively initiated to clear damaged mitochondria despite the presence of mitophagy regulators in oocytes, which leads to the transmission of dysfunctional mitochondria from the oocyte to the embryo. However, granulosa cells around oocytes can improve mitochondrial function through mitophagy, thereby improving oocyte developmental capacity. Furthermore, this review discusses recent work on the substances and environmental conditions that affect mitophagy in oocytes and granulosa cells, thus providing new directions for improving oocyte quality during assisted reproductive technology treatment.

Summary sentence

Oocytes have mitophagy regulators, but cannot activate mitophagy to remove damaged mitochondria under normal circumstances. Changes in oocyte and granulosa cell mitophagy caused by external stimuli can affect oocyte quality.

Graphical Abstract

External substances and environmental stimuli can cause changes of mitophagy in oocytes and granulosa cells, and affect mitochondrial function and oocyte quality. One plus sign indicates an increased level of mitophagy, and three plus signs indicate an excessive or abnormal increase. The minus sign represents reduced levels of mitophagy.