Mouse oocyte vitrification: the effects of two methods on maturing germinal vesicle breakdown oocytes

Abstract

Purpose Evaluation of viability and subsequent developmental ability of mouse germinal vesicle breakdown oocytes vitrified in conventional straws. Methods Oocytes with compact cumulus cells were cultured for 3 h in TCM199 medium GVBD and vitrified by two methods: the step-wise and single-step. After vitrification, the oocytes were thawed, and subjected to in vitro maturation and in vitro fertilization. Oocyte survival (postthaw) was assessed by morphological appearance and staining, using propidium iodide (PI)/Hoechst 33342. The oocyte maturation and fertilization rates were examined in vitro. Results In the single-step method the rates of post thaw survival, maturation to metaphase II and cleavage (2-cell embryos) were 58.68%, 56.41% and 38.63%, respectively. In the step-wise method, the corresponding rates were 81.75%, 68.59% and 51.80%, respectively. Conclusion Vitrification of mouse germinal vesicle breakdown oocytes by the step-wise method had the advantage of maintaining the viability and subsequent production of 2-cell embryos. In comparison with that in unvitrified control oocytes, the development of MII oocytes to 2-cell embryos was impaired following vitrification.

The Nuclear Maturation and Embryo Development of Mice Germinal Vesicle Oocytes with and without Cumulus Cell after Vitrification

“…We showed in our previous study that using step-wise vitrification method increased the rates of maturation, fertilization and blastocyste formation in GV oocytes. Since vitrification is a nonequilibrium cryopreservation method that needs a relatively high concentration of cryoprotectants, a step-wise addition of cryoprotectants may reduce the toxic effects of cryoprotectants and be considered to minimize damage due to extreme cell-volume expansion [13,37].…”

Influence of Insulin-Like Growth Factor-I on Maturation and Fertilization Rate of Immature Oocyte and Embryo Development in NMRI Mouse with TCM199 and α -MEM Medium

“…Cumulus cells have been considered to play an important role in oocyte maturation by keeping the oocyte under meiotic arrest, inducing meiotic resumption and by supporting cytoplasmic necessary for the transfer of nutrients and factors essential for oocyte development [9][10][11][12][13].…”

Cellular and Molecular Events that Occur in the Oocyte during Prolonged Ovarian Storage in Sheep

“…To gain further awareness of the biological consequences of prolonged transport time in stored oocytes, we examined cumulus cells and oocyte development in vitro. Cumulus cells play a critical role in oocyte maturation because they supply ions, metabolites and regulatory molecules that are necessary for meiotic progression, normal nuclear and cytoplasmic maturation of oocytes, and subsequent embryonic development after fertilization [ 37 , 38 ]. As expected, cumulus cells lost their supportive and protective functions when subjected to storage times longer than 7 h, since they showed decreased viability and impaired redox status and mitochondrial activity.…”