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

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.

Protective Effect and Mechanism of Melatonin on Cisplatin-Induced Ovarian Damage in Mice

“…In our experiments, we found that the expression of DRP1 and Fis1 expression was reduced in mice ovaries after CP treatment, which was consistent with previous studies that CP exerts its adverse effects on the human ovarian cancer SKOV3 cells through mitochondrial dynamics-related proteins [26]. Moreover, DRP1-mediated mitochondrial dynamics were involved in the effect of CP on acute kidney injury [27]. Our study also revealed that the new kinetic-related protein Fis1 was involved in the action of CP on the ovary.…”

The walnut-derived peptide TW-7 improves mouse parthenogenetic embryo development of vitrified MII oocytes potentially by promoting histone lactylation

“…Current research also investigated the mechanism by which oxidative stress adversely affected the embryo development. Previous studies suggested that mitochondrial dysfunction induced by oocyte vitrification exacerbated ROS production [ 21 , 68 ]. The excessive ROS in turn inhibited the activity of glycolytic pyruvate kinase M2 (PKM2) by promoting its phosphorylation, which consequently reduced the production of the glycolytic products like lactate [ 40 , 41 ].…”

Oxidative Stress and Oocyte Cryopreservation: Recent Advances in Mitigation Strategies Involving Antioxidants

“…It has been reported that 10 −7 mol/L melatonin can improve spindle morphology through MTRs, regulate the levels of MAD2 protein, an important component of the SAC, and subsequently improve the in vitro developmental potential of vitrified-warmed mouse GV-stage oocytes [ 88 ]. In addition, oocyte cryopreservation can lead to increased phosphorylation levels of kinesin-related protein 1 (Drp1), while 10 −7 mol/L melatonin was able maintain mitochondrial fission/fusion homeostasis via MTRs that reduce Drp1 phosphorylation levels, protecting mitochondrial function, reducing the release of pro-apoptotic genes and cytochrome C, and improving the survival rate of vitrified-warmed mouse GV-stage oocytes [ 130 ].…”