Human oocyte cryopreservation and the fate of cortical granules

Ghetler, Yehudith; Skutelsky, Ehud; Nun, Isaac Ben; Dor, Liah Ben; Amihai, Dina; Shalgi, Ruth

doi:10.1016/j.fertnstert.2005.12.061

Cited by 100 publications

(70 citation statements)

References 45 publications

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“…The one-step protocol seems to be associated to a higher clinical outcome [3], although this has not been confirmed through a prospective randomized control trial. Rather consistently, the presence of vacuoles was described by our group as well as by others in association with a variety of CRSC protocols [19,23,36]. It is tempting to hypothesize that vacuoles located peripherally may evolve from crypt-like invaginations and clusters of endocytic vesicles which form in the oocyte cortex following simple exposure to CPA, as shown by Schalkoff et al [41].…”

Section: Discussionsupporting

confidence: 58%

“…With the advent of improved protocols [4,34,35], novel ultrastructural evidence was generated. Comparing fresh oocytes with others frozen with a CRSC involving 0.1 mol/l sucrose as an extracellular CPA, Ghetler et al [36] found massive reduction in the number of CG as a effect of cryopreservation, concluding that stored oocytes should be microinjected rather than inseminated by standard IVF to prevent possible fertilization failure secondary to zona hardening. In effect, ICSI (intracytoplasmic sperm injection) had been suggested to be the elective route to achieve fertilization in cryopreserved oocytes [27] and has now become a standard of treatment [6,7,14,29].…”

Section: Discussionmentioning

confidence: 99%

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Qualitative and morphometric analysis of the ultrastructure of human oocytes cryopreserved by two alternative slow cooling protocols

Coticchio¹,

Borini²,

Distratis³

et al. 2010

J Assist Reprod Genet

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Purpose To ascertain possible cell damage from cryopreservation, the ultrastructure of human oocytes cryopreserved by slow cooling was assessed. Materials and methods Cryopreservation was performed through two protocols with one-step or two-step propanediol. Fresh control oocytes were examined for comparison. Samples were processed for transmission electron microscopy analysis. Results By light microscopy, both fresh and frozen-thawed oocytes appeared regularly rounded, with intact zona pellucida, and homogeneous cytoplasm. By electron microscopy observation, organelles were abundant and uniformly dispersed. Mitochondria-smooth endoplasmic reticulum associations appeared regular. However, both the amount and density of cortical granules appeared abnormally reduced in frozen-thawed samples. Slight to moderate vacuolization was also found in the ooplasm of oocytes of both frozen groups. Conclusions Slow cooling ensures a good overall preservation of human oocytes. However, cytoplasmic vacuolization and cortical granule loss appears associated with cryopreservation, irrespective of the protocol used.

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Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Qualitative and morphometric analysis of the ultrastructure of human oocytes cryopreserved by two alternative slow cooling protocols

Coticchio¹,

Borini²,

Distratis³

et al. 2010

J Assist Reprod Genet

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“…This was similar to our results. In a human study, it has been shown that the freezing process is a leading cause of the cortical granules reduction and emergence of vacuoles in the cytoplasm of mature and immature oocytes (Ghetler et al, 2006). These findings confirm our results.…”

Section: Discussionsupporting

confidence: 92%

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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“…The cause of zona hardening could be the use of the cryoprotectants ethylene glycol and/or 1,2-propanediol, both of which have been shown to cause Ca 2þ release when added to unfrozen oocytes [7,11]. This, in turn, could cause premature release of cortical granules and modification of the zona [58] and the plasma membrane. The ability of zona-free oocytes to be fertilized in this study demonstrates that, even if release of cortical granules modified the zona pellucida, sperm interaction with the plasma membrane was not impaired by the vitrification procedure in most cases.…”

Section: Mouse Oocyte Vitrification 151mentioning

confidence: 99%

Maturation, Fertilization, and the Structure and Function of the Endoplasmic Reticulum in Cryopreserved Mouse Oocytes1

Lowther

Weitzman

Maier

et al. 2009

Biology of Reproduction

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Oocyte cryopreservation is a promising technology that could benefit women undergoing assisted reproduction. Most studies examining the effects of cryopreservation on fertilization and developmental competence have been done using metaphase IIstage oocytes, while fewer studies have focused on freezing oocytes at the germinal vesicle (GV) stage, followed by in vitro maturation. Herein, we examined the effects of vitrifying GVstage mouse oocytes on cytoplasmic structure and on the ability to undergo cytoplasmic changes necessary for proper fertilization and early embryonic development. We examined the endoplasmic reticulum (ER) as one indicator of cytoplasmic structure, as well as the ability of oocytes to develop Ca 2+ release mechanisms following vitrification and in vitro maturation. Vitrified GV-stage oocytes matured in culture to metaphase II at a rate comparable to that of controls. These oocytes had the capacity to release Ca 2+ following injection of inositol 1,4,5-trisphosphate, demonstrating that Ca 2+ release mechanisms developed during meiotic maturation. The ER remained intact during the vitrification procedure as assessed using the lipophilic fluorescent dye DiI. However, the reorganization of the ER that occurs during in vivo maturation was impaired in oocytes that were vitrified before oocyte maturation. These results show that vitrification of GV-stage oocytes does not affect nuclear maturation or the continuity of the ER, but normal cytoplasmic maturation as assessed by the reorganization of the ER is disrupted. Deficiencies in factors that are responsible for proper ER reorganization during oocyte maturation could contribute to the low developmental potential previously reported in vitrified in vitro-matured oocytes.assisted reproductive technology, gamete biology, in vitro fertilization, meiosis

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Human oocyte cryopreservation and the fate of cortical granules

Cited by 100 publications

References 45 publications

Qualitative and morphometric analysis of the ultrastructure of human oocytes cryopreserved by two alternative slow cooling protocols

Qualitative and morphometric analysis of the ultrastructure of human oocytes cryopreserved by two alternative slow cooling protocols

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

Maturation, Fertilization, and the Structure and Function of the Endoplasmic Reticulum in Cryopreserved Mouse Oocytes1

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