High revivability of vitrified–warmed bovine mature oocytes after recovery culture with α-tocopherol

Abstract

The objective of this study was to investigate whether developmental competence of vitrified-warmed bovine oocytes can be improved by antioxidant treatment during recovery culture. In experiment 1, one of the two antioxidants (either L-ascorbic acid or a-tocopherol) was added as a supplement to the recovery culture medium to which postwarming oocytes were exposed for 2 h before IVF. The exposure to a-tocopherol had a positive effect on rescuing the oocytes as assessed by the blastocyst yield 8 days after the IVF (35.1-36.3% vs 19.2-25.8% in untreated postwarming oocytes). Quality of expanding blastocysts harvested on Day 8 was comparable between a-tocopherol-treated vitrification group and fresh control group in terms of total cell number and chromosomal ploidy. In experiment 2, level of reactive oxygen species, mitochondrial activity, and distribution of cortical granules in a-tocopherol-treated postwarming oocytes were assessed. No obvious differences from the control data were found in these parameters. However, the treatment with a-tocopherol increased the percentage of zygotes exhibiting normal single aster formation (90.3% vs 48.0% in untreated postwarming oocytes; 10 h post-IVF). It was concluded that a-tocopherol treatment of vitrified-warmed bovine mature oocytes during recovery culture can improve their revivability, as shown by the high blastocyst yield and the higher mean total cell number in the blastocysts.

Antioxidants and glycine can improve the developmental competence of vitrified/warmed ovine immature oocytes

“…In mouse, NAC supplementing of VWS and IVM medium of GV stage vitrified oocytes inhibited ROS activity and improved the mitochondrial distribution and developmental competence of the oocytes (Yue et al, ). In bovine while AA was ineffective, 2‐hr recovery culture with α‐tocopherol before IVF significantly improved the blastocyst development and single aster formation of vitrified/warmed MII stage oocytes (Yashiro et al, ). Despite the positive effects of the above additives as potential candidates for improving the oocyte cryopreservation procedures, some issues such as finding suitable antioxidant for each species or oocyte developmental stage (GV or MII), the amount and manner of using these compounds and the toxicity of these compounds still remained to be more investigated.…”

Quality of vitrified porcine immature oocytes is improved by coculture with fresh oocytes during in vitro maturation

“…That cryopreservation seriously reduced oocyte quality was the primary obstacle to using vitrified oocytes. Many attempts have been made to modify culture conditions for vitrified oocytes, including supplementation with antioxidants (Yashiro et al, ), treatment with a cyclic adenosine monophosphate modulator (Ezoe et al, ), or coculture with CCs (Casillas et al, ). In the present study, coculture with fresh oocytes during IVM meliorated meiotic progression, ROS level, mitochondrial and ER features, and gene expression patterns in CCs and oocytes, with enhanced developmental competence of vitrified porcine GV oocytes.…”

Cryopreservation of equine oocytes: looking into the crystal ball

“…The susceptibility of the equine oocyte to cryopreservation-induced damage is thought be related to the large amount of lipids present in the membranes and cytoplasm of equine oocytes, which may increase oxidative damage or lower membrane permeability, especially after lipid phase transition (Hochi et al 1996;Ambruosi et al 2009). Culturing the oocytes in media that minimise the production of lipids and the addition of several antioxidants in culture and vitrification media yielded promising results in other species and may improve equine oocyte vitrification (Abe et al 2002;Gupta et al 2007;Chankitisakul et al 2013;Yashiro et al 2015).…”