Bypassing the effect of zona pellucida changes on embryo formation following cryopreservation of bovine oocytes

Mavrides, Andreas; Morroll, David

doi:10.1016/j.ejogrb.2004.06.025

Cited by 45 publications

(43 citation statements)

References 11 publications

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“…Interestingly, similar conformational changes of the ZP protein secondary structure were reported in ovine oocytes following vitrification [14]. This protein transformation to a more ordered structure is in agreement with the cryopreservation-induced ZP mechanical hardening previously reported elsewhere [36, 37]. This conformational change, likely related to the premature release of cortical granules, undoubtedly contributes to ZP hardening.…”

Section: Discussionsupporting

confidence: 87%

“…This conformational change, likely related to the premature release of cortical granules, undoubtedly contributes to ZP hardening. In fact, cryopreservation leads to premature release of cortical granules that in turn determines ZP hardening, known to impair sperm penetration [13, 37–39]. It has also been reported that the simple exposure of oocytes to CPs may result in premature release of cortical granules [39–41].…”

Section: Discussionmentioning

confidence: 99%

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Raman-microscopy investigation of vitrification-induced structural damages in mature bovine oocytes

et al. 2017

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Although oocyte cryopreservation has great potentials in the field of reproductive technologies, it still is an open challenge in the majority of domestic animals and little is known on the biochemical transformation induced by this process in the different cellular compartments. Raman micro-spectroscopy allows the non-invasive evaluation of the molecular composition of cells, based on the inelastic scattering of laser photons by vibrating molecules. The aim of this work was to assess the biochemical modifications of both the zona pellucida and cytoplasm of vitrified/warmed in vitro matured bovine oocytes at different post-warming times. By taking advantage of Principal Component Analysis, we were able to shed light on the biochemical transformation induced by the cryogenic treatment, also pointing out the specific role of cryoprotective agents (CPs). Our results suggest that vitrification induces a transformation of the protein secondary structure from the α-helices to the β-sheet form, while lipids tend to assume a more packed configuration in the zona pellucida. Both modifications result in a mechanical hardening of this cellular compartment, which could account for the reduced fertility rates of vitrified oocytes. Furthermore, biochemical modifications were observed at the cytoplasmic level in the protein secondary structure, with α-helices loss, suggesting cold protein denaturation. In addition, a decrease of lipid unsaturation was found in vitrified oocytes, suggesting oxidative damages. Interestingly, most modifications were not observed in oocytes exposed to CPs, suggesting that they do not severely affect the biochemical architecture of the oocyte. Nevertheless, in oocytes exposed to CPs decreased developmental competence and increased reactive oxygen species production were observed compared to the control. A more severe reduction of cleavage and blastocyst rates after in vitro fertilization was obtained from vitrified oocytes. Our experimental outcomes also suggest a certain degree of reversibility of the induced transformations, which renders vitrified oocytes more similar to untreated cells after 2 h warming.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Raman-microscopy investigation of vitrification-induced structural damages in mature bovine oocytes

et al. 2017

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“…Many problems were found to be associated with chilling and freezing of immature, in vitro matured or ovulated oocytes, including abnormal spindle associated with disorganized microtubules and chromosomes (Rojas et al 2004;Succu et al 2007), altered distribution of cortical granules and increased polispermy or on the contrary, zona pellucida hardening by premature cortical granule exocitosis impairing fertilization (Mavrides and Morrol 2005;Morato et al 2008).…”

Section: Oocyte and Embryo Cryoinjuriesmentioning

confidence: 99%

Animal oocyte and embryo cryopreservation

Pereira¹,

Marques²

2008

Cell Tissue Bank

150

129

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Cryopreservation of oocytes and embryos is a crucial step for the widespread and conservation of animal genetic resources. However, oocytes and early embryos are very sensitive to chilling and cryopreservation and although new advances have been achieved in the past few years the perfect protocol has not yet been established. All oocytes and embryos suffer considerable morphological and functional damage during cryopreservation but the extent of the injury as well as differences in survival and developmental rates may be highly variable depending on the species, developmental stage and origin (for example, in vitro produced or in vivo derived, micromanipulated or not). Currently, there are two methods for gamete and embryos cryopreservation: slow freezing and vitrification. We have experienced both techniques but vitrification has become a viable and promising alternative to traditional approaches especially when dealing with in vitro produced or micromanipulated embryos and oocytes. Recently new strategies based on emerging studies in the field of lipid research have been used to reduce intracellular lipid content in bovine in vitro produced embryos and therefore increase their tolerance to micromanipulation and cryopreservation. The addition of a conjugated isomer of linoleic acid, the trans-10, cis-12 octadecadienoic acid to embryo culture medium more than twice improved embryo post-thawing viability after micromanipulation and vitrification. Vitrification was also used for the cryopreservation of embryos belonging to the Portuguese Animal Germplasm Bank project presently running at our facilities.

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“…They are surrounded by zona pellucida, which acts as an additional barrier to movement of water and CPs into and out of the oocyte. As a result of the freeze-thaw process, premature cortical granule exocytosis may take place, leading to zona pellucida hardening and making sperm penetration and fertilization impossible (Carroll et al 1990a, Mavrides & Morroll 2005, a process that can be overcome by the use of ICSI or subzonal sperm insertion. Oocytes also have high cytoplasmic lipid content that increases chilling sensitivity (Ruffing et al 1993).…”

Section: Oocyte Cryopreservation: the Difficultiesmentioning

confidence: 99%

Current progress in oocyte and embryo cryopreservation by slow freezing and vitrification

2011

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Preservation of female genetics is currently done primarily by means of oocyte and embryo cryopreservation. The field has seen much progress during its four-decade history, progress driven predominantly by research in humans, cows, and mice. Two basic cryopreservation techniques rule the field -controlled-rate freezing, the first to be developed, and vitrification, which, in recent years, has gained a foothold. While much progress has been achieved in human medicine, the cattle industry, and in laboratory animals, this is far from being the case for most other mammals and even less so for other vertebrates. The major strides and obstacles in human and other vertebrate oocyte and embryo cryopreservation will be reviewed here.

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Bypassing the effect of zona pellucida changes on embryo formation following cryopreservation of bovine oocytes

Cited by 45 publications

References 11 publications

Raman-microscopy investigation of vitrification-induced structural damages in mature bovine oocytes

Raman-microscopy investigation of vitrification-induced structural damages in mature bovine oocytes

Animal oocyte and embryo cryopreservation

Current progress in oocyte and embryo cryopreservation by slow freezing and vitrification

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