The effect of vitrification on ultrastructure of human in vitro matured germinal vesicle oocytes

Shahedi, Abbas; Hosseini, Ahmad; Khalili, Mohammad Ali; Norouzian, Mohsen; Salehi, Mohammad; Piriaei, A; Nottola, Stefania Annarita

doi:10.1016/j.ejogrb.2012.11.006

Cited by 44 publications

(38 citation statements)

References 39 publications

(44 reference statements)

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“…A study was conducted by Shahedi et al, to evaluate the effect of vitrification on ultrastructure of immature oocytes in fIVM and vIVM groups. Their results showed that normal oocytes surrounded by an intact and continuous membrane containing long and uniform microvilli (Shahedi et al, 2013). Their results about the integrity of the oocyte membrane confirmed our findings.…”

Section: Discussionsupporting

confidence: 81%

Assessment of Mouse Oocytes Ultrastructure Following Vitrification Before and After in vitro Maturation

et al. 2018

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IZADI, M.; EFTEKHAR, V. S. H.; AKBARI, H.; ASADI, S. M. & MOKHTARI, T.Assessment of mouse oocytes ultrastructure following vitrification before and after in vitro maturation. Int. J. Morphol., 36(1):180-188, 2018. SUMMARY:Vitrification is a physical process in which the concentrated cryoprotectant solution after exposure to extreme cold without ice crystal formation in living cells to be converted glassing state. In this study, maturation rate and ultrastructure of mouse oocytes followed by vitrification before or after in-virto maturation (IVM) were evaluated. A total of 373 germinal vesicle oocytes were obtained from ovaries and divided into three fresh IVM, IVM vitrified, vitrified IVM groups. Ten metaphase II oocytes were obtained from uterine tubes and considered as the control group. Oocytes in vitrified groups were vitrified by Cryotop using vitrification medium and kept in liquid nitrogen. The maturation media was a-MEM supplemented with rFSH + hCG. After 24-48 h of incubation, the oocytes were investigated for nuclear maturation and ultrastructural changes using transmission electron microscopy (TEM). The oocyte maturation rate in vIVM group was significantly lower than IVMv group, when the two groups were compared with vIVM had the highest maturity. The evaluation ultrastructure of the four groups showed that the number of cortical granules, microvilli and mitochondria-SER aggregates in vIVM group were lowest and the highest amongst the number of vacuoles. Zona pellucida was darker than the control group in two freeze groups vIVM and IVMv. Most similar groups to the control group were group vIVM, Group IVMv and ultimately vIVM group, respectively. According to the results, IVM procedure is more efficient when it is performed before oocyte vitrification.

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Section: Discussionsupporting

confidence: 81%

Assessment of Mouse Oocytes Ultrastructure Following Vitrification Before and After in vitro Maturation

et al. 2018

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“…However, due to the use of high concentrations of cryoprotectant solutions and fast changing temperatures during the vitrification process, there is an increasing concern for the potential impact of cryopreservation techniques on oocyte and embryo development, and especially on the health of the progeny [8] . Although numerous reports described pregnancies and live births after human oocyte cryopreservation [9] , the overall safety profile and the risk of cryopreservation techniques on human oocytes remain controversial [10,11] . Systematic analysis of cryopreservation on human oocytes, including their potential for maturation, is a key imperative.…”

Section: Introductionmentioning

confidence: 99%

Ultrastructural Changes and Methylation of Human Oocytes Vitrified at the Germinal Vesicle Stage and Matured in vitro after Thawing

Liu

Zhou

Chu

et al. 2016

Gynecol Obstet Invest

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Aim: The study aimed to assess the effect of in vitro vitrification and maturation on the nuclear configuration, cytoplasmic maturation and global DNA methylation pattern of human germinal vesicle (GV) stage oocytes. Methods: Human oocytes from infertile women were randomly assigned to one of 3 groups: (i) metaphase II (MII) oocytes matured in vivo (vivo-MII, n = 56) as controls; (ii) MII oocytes matured in vitro (vitro-MII, n = 106); and (iii) MII oocytes that were vitrified at the GV stage, warmed and matured in vitro (cryo-MII, n = 122). All MII oocytes were fixed and immunofluorescence staining for spindle, chromosome, mitochondrion and cortical granules (CGs) were performed; examination was done using immunofluorescence laser scanning confocal microscope. The expression of 5-methycytosine in these MII oocytes was also assessed. Results: No significant difference was observed between vitro-MII and cryo-MII groups with respect to oocyte maturation rate (72.4 vs. 78.3%). No significant differences were observed in the distribution of mitochondria, migration of CG and global DNA methylation pattern among the 3 study groups. However, the abnormal configuration of spindle and chromosome was significantly higher in cryo-MII group (78.9 and 84.2%) as compared to that in the vitro-MII (45.0 and 50.0%, p < 0.05) and vivo-MII groups (27.3 and 36.4%, p < 0.05). Conclusion: GV oocytes appeared to resist vitrification and retain their potential for maturation to MII stage oocytes after thawing. However, GV oocytes vitrification combined with in vitro maturation could affect the organization of spindle and chromosome.

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“…Whereas, Bax is a pro-apoptotic molecule and accelerates the cell death (13). The ultra-structural changes in the distribution pattern of the cortical granules (CGs), as well as cytoplasmic structural changes followed by vitrification of GV oocytes were reported in our previous study (14). Nonetheless, the influence of vitrification on the gene expression has been predominantly studied in mice; there are not a lot of studies in human oocytes until now with promising outcomes.…”

Section: Introductionmentioning

confidence: 99%

“…(Figure 1 and Table 4). (14,17). This damage, in turn inversely affects the ability of oocytes to respond to signals to continue its development.…”

Section: The Effect Of Vitrification On Gene Expression Of Human Oocytesmentioning

confidence: 99%

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Vitrification Affects Nuclear Maturation and Gene Expression of Immature Human Oocytes

et al. 2017

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Background: Vitrification of oocytes is a fast-freezing technique, which may affect the quality of human oocytes, and consequently affects the embryo development, pregnancy and birth. The aim of the current study was to investigate the consequences of in-vitro vitrification on maturation status of immature human oocytes, as well as expression levels of stress-and apoptosis-related genes. Materials and Methods:The total of 213 human immature oocytes routinely discarded from assisted reproduction clinics were collected and divided into two groups including: (I) fresh germinal vesicle (GV) oocytes (n=106) matured invitro (fIVM) , and (II) GV oocytes (n=107) that were initially vitrified, then matured in in-vitro (vIVM). After 36 hours of incubation, the oocytes were evaluated for nuclear maturation and expression level of DNA methyltransferase (DNMT1), stress-related genes (Sod1 and Hsp70), and apoptosis-related genes (Bax and Bcl-2) by quantitative Real-Time PCR. Results: Oocyte maturation rates were reduced in vIVM compared to fIVM oocytes (P=0.001). The expression of stress (Sod1 and Hsp70), and apoptosisrelated genes (Bax and Bcl-2) in vIVM were significantly higher compared to fIVM group. Additionally, pro-apoptotic gene was up-regulated 4.3 times more than anti-apoptotic gene in vIVM oocyte. However, DNMT1 gene expression was reduced in vIVM oocyte (P = 0.047). Conclusion:The low survival rate of vitrified in-vitro matured GV oocytes could definitely be explained by the alterations of their gene expression profile.

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The effect of vitrification on ultrastructure of human in vitro matured germinal vesicle oocytes

Cited by 44 publications

References 39 publications

Assessment of Mouse Oocytes Ultrastructure Following Vitrification Before and After in vitro Maturation

Assessment of Mouse Oocytes Ultrastructure Following Vitrification Before and After in vitro Maturation

Ultrastructural Changes and Methylation of Human Oocytes Vitrified at the Germinal Vesicle Stage and Matured in vitro after Thawing

Vitrification Affects Nuclear Maturation and Gene Expression of Immature Human Oocytes

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