Maturation ability after transfer of freeze‐dried germinal vesicles from porcine oocytes

Abstract

The purpose of this study was to examine whether freeze-dried germinal vesicles (GV) can be matured in vitro after being injected into enucleated fresh oocytes in pigs as an alternative method for conservation of genetic resources. Although no reduction of the size of GV (p = .094), resveratrol treatment significantly enhanced the survival rates following GV transfer (GVT) (p < .001). Supplementation with 100 or 200 mmol/L trehalose in freeze-drying medium significantly increased the proportions of GVs with intact nuclear membrane and DNA integrity compared with the control group. Following transfer of freeze-dried GVs into enucleated fresh oocytes, the proportion of reconstructed oocytes reached the metaphase-II stage (2.4% ± 1.4%) was significantly lower (p < .05) than that of the in vitro matured control group (83.2% ± 2.5%), it was comparable with the GVT control group (7.4% ± 2.7%). The rates of freeze-dried GVs with intact nuclear membrane and DNA stored at -20°C for 5 days were significantly higher (p < .05) than those at 4°C and room temperature. The rates of intact nuclear membrane and DNA in the freeze-dried GV stored for 15 or 30 days at -20, 4°C and RT were not significantly different. In conclusion, matured oocytes were produced derived from freeze-dried GVs.

Desiccation and supra‐zero temperature storage of cat germinal vesicles lead to less structural damage and similar epigenetic alterations compared to cryopreservation

“…The higher resilience of GV than the whole oocytes has allowed exploration of alternative preservation methods specifically targeting GV alone (Holt, ). A recent article by Dang‐Nguyen et al () reported that oocytes reconstituted with freeze‐dried porcine GVs could be matured in vitro. Our laboratory also has previously demonstrated the retention of structure and meiotic competence of GVs after air‐dry and rehydration in the domestic cat ( Felis catus ) model (Graves‐Herring et al, ).…”

Long-term preservation of germ cells and gonadal tissues at ambient temperatures

“…Regarding the female gamete, freeze-dried porcine nuclei (germinal vesicles) can resume meiosis after transfer into an enucleated oocyte (Dang-Nguyen et al 2018). Further analysis demonstrated that a small portion of dried germinal vesicles stored in glass vial at non-freezing temperatures retained intact nuclear envelope and/or DNA.…”

“…1). Glass ampoules (Kamada et al 2018) or glass vials (Dang-Nguyen et al 2018) have been traditionally used to store lyophilized germplasms. The main inconvenience is that ampoules are breakable.…”

Production of mouse offspring from zygotes fertilized with freeze-dried spermatids

“…However, until recently, the only type of FD cells from which offspring have been successfully produced thus far are spermatozoa. Oocytes or embryos are thought to be di cult to freeze dry because of the large amount of cytoplasm that they contain 15 . On the other hand, although somatic cells or spermatids have a similar size with spermatozoa, it has not been possible long time to produce offspring after subjecting them to an FD treatment [16][17][18][19] .…”