Glutathione Ethyl Ester Protects In Vitro-Maturing Bovine Oocytes against Oxidative Stress Induced by Subsequent Vitrification/Warming

Abstract

This study aimed to examine whether the addition of glutathione ethyl ester (GSH-OEt) to the in vitro maturation (IVM) medium would improve the resilience of bovine oocytes to withstand vitrification. The effects of GSH-OEt on spindle morphology, levels of reactive oxygen species (ROS), mitochondrial activity and distribution, and embryo developmental potential were assessed together with the expression of genes with a role in apoptosis (BAX, BCL2), oxidative-stress pathways (GPX1, SOD1), water channels (AQP3), implantation (IFN-τ) and gap junctions (CX43) in oocytes and their derived blastocysts. Vitrification gave rise to abnormal spindle microtubule configurations and elevated ROS levels. Supplementation of IVM medium with GSH-OEt before vitrification preserved mitochondrial distribution pattern and diminished both cytoplasmic and mitochondrial ROS contents and percentages of embryos developing beyond the 8-cell stage were similar to those recorded in fresh non-vitrified oocytes. Although not significantly different from control vitrified oocytes, vitrified oocytes after GSH-OEt treatment gave rise to similar day 8-blastocyst and hatching rates to fresh non-vitrified oocytes. No effects of GSH-OEt supplementation were noted on the targeted gene expression of oocytes and derived blastocysts, with the exception of GPX1, AQP3 and CX43 in derived blastocysts. The addition of GSH-OEt to the IVM medium before vitrification may be beneficial for embryo development presumably as the consequence of additional anti-oxidant protection during IVM.

Chrysin induces autophagy through the inactivation of the ROS‑mediated Akt/mTOR signaling pathway in endometrial cancer

“…1E , chrysin notably increased the proportion of apoptotic cells. Bax is a pro-apoptotic protein that leads to cell death, whereas Bcl-2 is an anti-apoptotic protein that promotes cell survival ( 21 ). Western blotting revealed that the treatment of HEC-1A and Ishikawa cells with chrysin for 48 h increased the level of Bax and decreased the expression of Bcl-2 ( Fig.…”

Effect of cryoprotectant concentration on bovine oocyte permeability and comparison of two membrane permeability modelling approaches

“…The in vitro maturation (IVM) procedure followed has been described previously 49 . Briefly, ovaries from slaughtered postpubertal heifers (12–18 months old) were transported from a local slaughterhouse to the laboratory in saline solution (0.9% NaCl) at 35–37 °C within 2 h. Immature cumulus-oocyte complexes (COCs) were aspirated from 3 to 8 mm follicles using an 18-gauge needle attached to a 5 mL syringe.…”

Resveratrol enhanced mitochondrial recovery from cryopreservation‐induced damages in oocytes and embryos

“… 27 , 28 Therefore, the effect of antioxidants on oocytes and embryo following vitrification has been extensively studied; supplementation of culture medium of vitrified‐warmed oocytes or embryos with melatonin, glutathione ethyl‐ester, N‐acetyl cysteine, α‐tocopherol, or coenzyme Q reduced ROS levels and improved oocyte viability as well as embryo development in equine, cows, and mice. 6 , 29 , 30 , 31 , 32 In addition, supplementation of vitrified‐warming solution with acetyl‐L‐carnitine, N‐acetyl‐cysteine, and lipoic acid improved the cell number of the blastocysts and fetal development in mice. 33 Furthermore, addition of vitamin E to the culture medium of vitrified‐warming ovarian tissue improved oocyte and subsequent blastocyst stage development.…”

“…A study in humans showed that vitrified‐warmed oocytes have low ATP levels and mitochondrial membrane potential, abnormal mitochondrial configuration and localization, and ROS and intracytoplasmic Ca levels. 4 , 5 , 6 In addition, transition electron microscope revealed that mitochondria in vitrified‐warmed embryos had swollen morphology. 7 , 8 , 9 In our studies based on porcine oocytes, bovine eight‐cell stage and blastocyst stage embryos, ATP content, mitochondrial genome integrity and developmental ability in cryopreserved samples was low compared with those fresh counterparts.…”