Melatonin Promotes in vitro Development of Vitrified-Warmed Mouse GV Oocytes, Potentially by Modulating Phosphorylation of Drp1

Jianpeng Qin; Shichao Guo; Jinyu Yang; Izhar Hyder Qazi; Bo Pan; Tianyi Lv; Shengqin Zang; Yi Fang; Guangbin Zhou

doi:10.3389/fvets.2021.752001

Melatonin Promotes in vitro Development of Vitrified-Warmed Mouse GV Oocytes, Potentially by Modulating Phosphorylation of Drp1

Front Vet Sci. 2021 Sep 24:8:752001. doi: 10.3389/fvets.2021.752001. eCollection 2021.

Authors

Jianpeng Qin¹, Shichao Guo¹, Jinyu Yang¹, Izhar Hyder Qazi², Bo Pan¹, Tianyi Lv¹, Shengqin Zang¹, Yi Fang³, Guangbin Zhou¹

Affiliations

¹ Department of Animal Science, Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China.
² Department of Veterinary Anatomy and Histology, Shaheed Benazir Bhutto University of Veterinary and Animal Sciences, Sakrand, Pakistan.
³ Department of Grassland Resources and Animal Husbandry, Jilin Provincial Key Laboratory of Grassland Farming, Northeast Institute of Geography and Agoecology, Chinese Academy of Sciences, Changchun, China.

Abstract

Previous studies have shown that melatonin can mitigate cryopreservation-induced mitochondrial dysfunction in oocytes; however, the underlying molecular mechanism remains unclear. The objective of the present study was to investigate whether melatonin can improve the mitochondrial function during in vitro maturation of vitrified-warmed mouse germinal vesicle (GV) oocytes by modulating phosphorylation of dynamin related protein 1 (Drp1). Vitrification/warming procedures resulted in the following: (1) After cryopreservation of mouse GV oocytes, the phosphorylation level of Drp1 at Ser616 (p-Drp1 Ser616) in metaphase II (MII) oocytes was increased (P < 0.05). Furthermore, the rates of in vitro maturation, cleavage and blastocyst formation after parthenogenetic activation were decreased (P < 0.05). (2) In MII oocytes, the expression levels of translocase of the mitochondrial outer membrane 20 (TOMM20), mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) content, and mRNA levels of mitochondrial biogenesis-related genes (Sirt1, Pgc-1α, Tfam) were all decreased (P < 0.05), and (3) Reactive oxygen species (ROS) level, early apoptosis level, Cytochrome C release and mRNA levels of pro-apoptotic related genes (Bax, Caspase9, Caspase3) in MII oocytes were all increased (P < 0.05). The results of this study further revealed that negative impacts of GV oocyte cryopreservation were mitigated by supplementation of warming and in vitro maturation media with 10^-7mol /L melatonin or 2 x 10^-5mol/L Mdivi-1 (Drp1 inhibitor). Therefore, we concluded that 10^-7mol/L melatonin improved mitochondrial function, reduced oxidative stress and inhibited apoptosis by regulating phosphorylation of Drp1, thereby enhancing in vitro development of vitrified-warmed mouse GV oocytes.

Keywords: apoptosis; drp1 phosphorylation; melatonin; mitochondrial; oocyte cryopreservation.