DRP1 deficiency induces mitochondrial dysfunction and oxidative stress-mediated apoptosis during porcine oocyte maturation

Background: Environmental pollution induces oxidative stress and Apoptosis in mammalian oocytes, which can cause defects in reproduction; however, the molecular regulation of oxidative stress in oocytes is still largely unknown. In the present study, we identified that dynamin-related protein 1 (DRP1) is an important molecule regulating oocyte mitochondrial function and preventing oxidative stress/Apoptosis. DRP1 is a member of the Dynamin GTPase superfamily localized at the mitochondrial-endoplasmic reticulum interaction site, where it regulates the fission of mitochondria and other related cellular processes.

Results: Our results show that DRP1 was stably expressed during different stages of porcine oocyte meiosis, and might have a potential relationship with mitochondria as it exhibited similar localization. Loss of DRP1 activity caused failed porcine oocyte maturation and cumulus cell expansion, as well as defects in polar body extrusion. Further analysis indicated that a DRP1 deficiency caused mitochondrial dysfunction and induced oxidative stress, which was confirmed by increased Reactive Oxygen Species levels. Moreover, the incidence of early Apoptosis increased as detected by positive Annexin-V signaling.

Conclusions: Taken together, our results indicate that DRP1 is essential for porcine oocyte maturation and that a DRP1 deficiency could induce mitochondrial dysfunction, oxidative stress, and Apoptosis.