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Campos Cassavia Cintra de Oliveira L, Queiroz Vacari G, Maurício Barbanti Duarte J. A Method to Freeze Skin Samples for Cryobanks: A Test of Some Cryoprotectants for an Endangered Deer. Biopreserv Biobank 2024; 22:211-216. [PMID: 37944047 DOI: 10.1089/bio.2023.0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023] Open
Abstract
The genetic diversity of endangered deer species, such as Mazama jucunda, can be preserved with the help of somatic cell cryopreservation. This procedure allows obtaining several cells from the individual even after its death, which is very important for applications in reproductive biotechnologies. This study's objective was to test cryopreservation protocols of skin fragments of M. jucunda, using different cryoprotectants in slow freezing. We evaluated four treatments, composed of three cryoprotectants, dimethyl sulfoxide (DMSO), polyvinylpyrrolidone (PVP), and ethylene glycol (EG), used alone and in combination. There was also a control group where the tissue did not undergo cryopreservation. Skin fragments were collected from the medial region of the pelvic limbs of three individuals. Each fragment was divided into 10 equal parts, standardized by weight, making two pieces for each treatment and control from each animal. The collected fragments were evaluated in culture, based on the speed of occupation of the free spaces of the cell culture flask. Cell viability was also evaluated using Trypan Blue dye and the mitotic index to understand the effect of toxicity and freezing on cell membrane integrity and cell division capacity, respectively. The treatments that used association with PVP proved to be more damaging to the cells, taking longer to reach confluence. EG alone showed better results than DMSO in the slow-freezing protocol. Clinical Trial Registration Number is 1390/21.
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Affiliation(s)
- Laura Campos Cassavia Cintra de Oliveira
- Departamento de Zootecnia, Deer Conservation and Research Center (NUPECCE), Faculdade de Ciências Agrárias e Veterinárias, São Paulo State University, Jaboticabal, Brazil
| | - Gabrielle Queiroz Vacari
- Departamento de Zootecnia, Deer Conservation and Research Center (NUPECCE), Faculdade de Ciências Agrárias e Veterinárias, São Paulo State University, Jaboticabal, Brazil
| | - José Maurício Barbanti Duarte
- Departamento de Zootecnia, Deer Conservation and Research Center (NUPECCE), Faculdade de Ciências Agrárias e Veterinárias, São Paulo State University, Jaboticabal, Brazil
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Zhu Y, Zhang QJ, Feng HL, Luo J, Miao S, Jiang MX. Automation in vitrification and thawing of mouse oocytes and embryos. Front Cell Dev Biol 2023; 11:1330684. [PMID: 38178872 PMCID: PMC10764471 DOI: 10.3389/fcell.2023.1330684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 11/27/2023] [Indexed: 01/06/2024] Open
Abstract
Vitrification is a common technique for cryopreserving oocytes or embryos. However, manual vitrification is tedious and labor-intensive, and can be subject to variations caused by human factors. To address these challenges, we developed an automated vitrification-thawing system (AVTS) based on a cryo-handle. Our study firstly assessed the efficiency of cryoprotectant exchange through comparing the osmolalities of fresh and collected solutions during automated vitrification and thawing, and evaluated the cooling and warming rates of the cryo-handle. We also compared mouse oocyte survival, fertilization and embryo development after thawing and ICSI, and the development of re-frozen cleavage embryos between manual operation and automated system. The results showed that the osmolalities of collected samples were within normal range and comparable to fresh solutions. Furthermore, the automated system could obtain the reliable cooling and warming rates. Particularly, there were no significant differences in oocyte survival rates, fertilization rates, and subsequent embryo development and its quality between two procedures. Our findings suggest that AVTS has no impact on osmolalities of vitrification and thawing solutions, ensuring the proper exchange of cryoprotectants. The cryo-handle also shows the ability to achieve reliable cooling and warming rates, which benefits for the cryopreservation and thawing process. Moreover, the results from mouse oocytes and embryos indicate that automated system has effectively maintained the survival and fertilization of frozen oocytes and supported subsequent embryo development. Therefore, the automated vitrification and thawing system will inevitably represent a superior alternative to manual operation.
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Affiliation(s)
- Yan Zhu
- Guangdong Second Provincial General Hospital, Guangzhou, China
| | - Quan-Jun Zhang
- Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Huai L. Feng
- New York Fertility Center, New York-Prebyterian Healthcare System Affiliate Weill Cornell Medical College, New York, NY, United States
| | - Jin Luo
- T Stone Robotics Institute, Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shenzen, China
| | - Shu Miao
- Department of Automation, Tsinghua University, Beijing, China
| | - Man-Xi Jiang
- Guangdong Second Provincial General Hospital, Guangzhou, China
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Effect of embryo cryopreservation duration on pregnancy-related complications and birthweight after frozen-thawed embryo transfer: a retrospective cohort study. J Dev Orig Health Dis 2021; 13:187-196. [PMID: 33947503 DOI: 10.1017/s2040174421000192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Frozen embryo transfer (FET) has been adopted by growing number of reproductive medicine centers due to the improved outcome compared with fresh embryo transfer. However, few studies have focused on the impact of embryo cryopreservation duration on pregnancy-related complications and neonatal birthweight. Thus, a retrospective cohort study including all FET cycles with livebirth deliveries in a university affiliated hospital from May 2010 to September 2017 was conducted. These deliveries were grouped by the cryopreservation duration of the transferred embryo (≤3 months, 4-6 months, 7-12 months, and >12 months). The associations between embryo cryopreservation duration and pregnancy-related complications were evaluated among the groups using multinomial logistic regression. Neonatal birthweight was compared according to the stratification of singletons and multiples using multinomial and multilevel logistic regression, respectively. Among all 12,158 FET cycles, a total of 3864 livebirth deliveries comprising 2995 singletons and 1739 multiples were included. Compared with those within 3 months, women undergoing FET after a cryopreservation time longer than 3 months did not show any increased risk of gestational diabetes mellitus, gestational hypertension, preeclampsia, meconium staining of the amniotic fluid, or preterm birth. Furthermore, the risk of lower birthweight, macrosomia, small-for-gestational-age, or large-for-gestational-age for either singletons or multiples was not affected by long-term cryopreservation. In summary, embryo cryopreservation duration does not have negative effects on pregnancy-related complications or birthweight after FET.
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Bonte D, Thys V, De Sutter P, Boel A, Leybaert L, Heindryckx B. Vitrification negatively affects the Ca 2+-releasing and activation potential of mouse oocytes, but vitrified oocytes are potentially useful for diagnostic purposes. Reprod Biomed Online 2019; 40:13-25. [PMID: 31740224 DOI: 10.1016/j.rbmo.2019.09.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/13/2019] [Accepted: 09/23/2019] [Indexed: 10/25/2022]
Abstract
RESEARCH QUESTION To what extent does vitrification affect the Ca2+-releasing and activation potential of mouse oocytes, which are commonly used to determine the oocyte activation potential of human spermatozoa? DESIGN The effect of mouse oocyte vitrification on Ca2+ dynamics and developmental competence after oocyte activation was assessed and compared with fresh mouse oocytes. Moreover, the Ca2+ store content of the endoplasmic reticulum was determined at different time points during the vitrification-warming procedure. Finally, the Ca2+ pattern induced by cryoprotectant exposure was determined. RESULTS After human sperm injection into mouse oocytes, Ca2+ dynamics but not fertilization rates were significantly altered by vitrification warming (P < 0.05). Ca2+ dynamics in response to SrCl2 or ionomycin were also altered by oocyte vitrification. In contrast, activation and blastocyst rates after SrCl2 exposure were not affected (P > 0.05), whereas activation rates after ionomycin exposure were significantly lower in vitrified-warmed oocytes (P < 0.05); blastocyst rates were not affected (P > 0.05). Cryoprotectant exposure was associated with a strong drop in endoplasmic reticulum Ca2+ store content. Oocytes rapidly recovered during warming and recovery in Ca2+-containing media; a threshold area under the curve of Ca2+ dynamics to obtain activation rates above 90% was determined. CONCLUSIONS Vitrified-warmed mouse oocytes display reduced Ca2+-releasing potential upon oocyte activation, caused by cryoprotectant exposure. With adapted classification criteria, these oocytes could be used for diagnosing oocyte activation deficiencies in patients. Evaluating the Ca2+-signalling machinery in vitrified-warmed human oocytes is required.
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Affiliation(s)
- Davina Bonte
- Ghent-Fertility and Stem cell Team (G-FaST), Department of Human Structure and Repair, Ghent University Hospital, C. Heymanslaan 10, Ghent 9000, Belgium.
| | - Vanessa Thys
- Ghent-Fertility and Stem cell Team (G-FaST), Department of Human Structure and Repair, Ghent University Hospital, C. Heymanslaan 10, Ghent 9000, Belgium
| | - Petra De Sutter
- Ghent-Fertility and Stem cell Team (G-FaST), Department of Human Structure and Repair, Ghent University Hospital, C. Heymanslaan 10, Ghent 9000, Belgium
| | - Annekatrien Boel
- Ghent-Fertility and Stem cell Team (G-FaST), Department of Human Structure and Repair, Ghent University Hospital, C. Heymanslaan 10, Ghent 9000, Belgium
| | - Luc Leybaert
- Physiology group, Department of Basic and Applied Medical Sciences, Ghent University, C. Heymanslaagn 10, GhentGhent 9000, Belgium
| | - Björn Heindryckx
- Ghent-Fertility and Stem cell Team (G-FaST), Department of Human Structure and Repair, Ghent University Hospital, C. Heymanslaan 10, Ghent 9000, Belgium
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KALITA KRISHNA, DEKA BC, BISWAS RK, BARUA PM, BORAH P, DUTTA DJ, DAS SK. Effect of supplementation of vitrification solution on post-thaw survivability rate of porcine follicular oocytes. THE INDIAN JOURNAL OF ANIMAL SCIENCES 2019. [DOI: 10.56093/ijans.v89i8.93017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Oocytes (510) with two or more cumulus cell layers adhered to zona pellucida obtained by aspiration from follicles (2–8 mm dia) of 127 abattoir porcine ovaries were utilized to study the effect of supplementation of 0.5 M sucrose (Suc), 50 mg/ml polyvinyl pyrrolidone (PVP) and Suc + PVP into two different vitrification solutions, i.e. 35% concentration of both ethylene glycol (EG)+ propylene glycol (PG) and EG + dimethyl sulphoxide (DMSO). Vitrified post-thaw oocytes with intact zona pellucida and vitelline membrane, normal spherical shape and dark and evenly granulated cytoplasm under a stereo-zoom microscope were considered as viable. Out of the three supplements treatments, supplementation with sucrose + PVP combination and sucrose alone resulted in significantly higher mean post-thaw survivability rate of vitrified oocytes both for EG + PG and EG + DMSO as compared to the supplementation with PVP alone. It was concluded that addition of sucrose alone or in combination with PVP in vitrification solution, significantly improved survivability of vitrified porcine follicular oocytes.
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Fujihara M, Kaneko T, Inoue-Murayama M. Vitrification of canine ovarian tissues with polyvinylpyrrolidone preserves the survival and developmental capacity of primordial follicles. Sci Rep 2019; 9:3970. [PMID: 30850725 PMCID: PMC6408471 DOI: 10.1038/s41598-019-40711-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 02/22/2019] [Indexed: 12/24/2022] Open
Abstract
Ovarian tissue cryopreservation combined with immature follicle development can preserve female fertility in wildlife, regardless of age or reproductive timing. To investigate the effects of different cryopreservation methods and cryoprotectants on follicular survival and developmental capacity, ovarian cortical pieces from 15 dogs were cryopreserved by slow freezing or vitrification with different additional cryoprotectants as follows: dimethyl sulfoxide (DMSO), polyvinylpyrrolidone (PVP), combined DMSO and PVP (each at half the concentration of when used independently), or none (control). Cryopreserved ovarian tissues were evaluated by neutral red staining, histology, and xenotransplantation assays. Among cryopreservation conditions tested, vitrification with combined DMSO and PVP significantly improved the maintenance of follicular morphology compared to that in control. Furthermore, ovarian tissues vitrified using this condition maintained follicle morphology and developmental capacity 9 weeks after grafting, as shown by an increased percentage of primary and secondary follicles and a significant decrease in the transition stage from primordial to primary stage follicles 5 and 9 weeks after grafting. In contrast, slow freezing and control groups lost intact follicles by 5 weeks after grafting. The described cryopreservation techniques, which preserve canine follicle development, will build the foundation of ovarian tissue cryopreservation to preserve female fertility in wild canids.
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Affiliation(s)
- Mayako Fujihara
- Wildlife Research Center, Kyoto University, Kyoto, 606-8203, Japan.
| | - Takehito Kaneko
- Division of Science and Engineering, Graduate School of Arts and Science, Iwate University, Morioka, 020-8551, Japan.,Department of Chemistry and Biological Sciences, Faculty of Science and Engineering, Iwate University, Morioka, 020-8551, Japan
| | - Miho Inoue-Murayama
- Wildlife Research Center, Kyoto University, Kyoto, 606-8203, Japan.,Wildlife Genome Collaborative Research Group, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
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Wang Y, Zhang ML, Zhao LW, Kuang YP, Xue SG. Enhancement of the efficiency of oocyte vitrification through regulation of histone deacetylase 6 expression. J Assist Reprod Genet 2018; 35:1179-1185. [PMID: 29974369 DOI: 10.1007/s10815-018-1221-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 05/22/2018] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVE Successful oocyte vitrification (OV) is critical for cryopreservation of the oocytes from female patients with infertility, polycystic ovaries, and gynecologic cancers. Recent evidence suggests that relatively low levels of histone acetylation are critical for maintenance of the maturation capacity of cryopreserved oocytes. However, previous studies have only demonstrated a key role of histone deacetylases (HDAC) 1 and 2 in the cryopreservation of oocytes. METHODS In this study, we investigated the role of HDAC6 in these settings. We found that mouse oocytes with low HDAC6 levels decreased survival rate, cleavage rate, and blastocyst rate after OV. Bioinformatics analyses were used to predict HDAC6-targeting microRNAs (miRNAs), while the functional binding of miRNAs to HDAC6 mRNA was evaluated by a dual luciferase reporter assay. RESULTS Among all HDAC6-targeting miRNAs, we detected expression of miR-558, miR-527, and miR-762 in mouse oocytes. Specifically, we found that only miR-762 significantly inhibited protein translation of HDAC6 via binding to the 3'-UTR of the HDAC6 mRNA. Transfection of oocytes with HDAC6 or antisense of miR-762 significantly increased the survival rate, the cleavage rate, and blastocyst rate after OV. CONCLUSION As a result, our data suggest that induction of HDAC6 levels by miR-762 suppression may improve the current protocol for OV.
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Affiliation(s)
- Yao Wang
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Road, Shanghai, 200011, China.,Center of Reproductive Medicine, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, 200135, China
| | - Mei-Lin Zhang
- Center of Reproductive Medicine, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, 200135, China.,Shanghai Key Laboratory for Assisted Reproduction and Reproductive Genetics, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200135, China
| | - Lei-Wen Zhao
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Road, Shanghai, 200011, China
| | - Yan-Ping Kuang
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Road, Shanghai, 200011, China
| | - Song-Guo Xue
- Department of Assisted Reproduction, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, 639 Zhi Zao Ju Road, Shanghai, 200011, China.
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Abstract
Current freezing technology, especially the vitrification method, has markedly improved oocyte survival rate after warming, and the pregnancy rate is comparable to that achieved with fresh oocytes. However, most groups report using oocytes matured in vivo for vitrification. Although immature oocytes can be vitrified successfully, clinical outcomes do not reach that of vitrification of matured oocytes. The current literature suggests that oocytes should be vitrified at mature metaphase II (M-II) stage following IVM rather than at the immature germinal vesicle (GV) stage, because the potential for oocyte maturation is reduced when vitrification is performed on immature oocytes at the GV stage.
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Affiliation(s)
- Ri-Cheng Chian
- Department of Obstetrics and Gynecology, McGill University, 687 Pine Avenue West, H3A 1A1, Montreal, Canada.
| | - Yixin Xu
- Department of Obstetrics and Gynecology, McGill University, 687 Pine Avenue West, H3A 1A1, Montreal, Canada
| | - Dana Keilty
- Department of Obstetrics and Gynecology, McGill University, 687 Pine Avenue West, H3A 1A1, Montreal, Canada
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Pan Y, Cui Y, He H, Baloch AR, Fan J, Xu G, He J, Yang K, Li G, Yu S. Developmental competence of mature yak vitrified-warmed oocytes is enhanced by IGF-I via modulation of CIRP during in vitro maturation. Cryobiology 2015; 71:493-8. [PMID: 26519204 DOI: 10.1016/j.cryobiol.2015.10.150] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 10/24/2015] [Accepted: 10/26/2015] [Indexed: 12/24/2022]
Abstract
The objective of this study was to investigate whether developmental competence of mature vitrified-warmed yak (Bos grunniens) oocytes can be enhanced by supplemented insulin-like growth factor I (IGF-1) during in vitro maturation (IVM), and its relationship with the expression of cold-inducible RNA-binding protein (CIRP). In experiment 1, immature yak oocytes were divided into four groups, and IVM supplemented with 0, 50, 100 and 200 ng/mL IGF-1 was evaluated; the mRNA and protein expression levels of CIRP in mature oocytes in the four groups were evaluated using quantitative real-time PCR and western blotting analyses. In experiment 2, the mature yak oocytes in the four groups were cryopreserved using the Cryotop (CT) method, followed by chemical activation and in vitro culture for two days and eight days to determine cleavage, blastocyst rates, and total cell number in the blastocysts. Mature yak oocytes without vitrification served as a control group. The outcomes were as following: (1) the expression of CIRP in the matured oocytes was up-regulated in the IGF-1 groups and was highest expression was observed in the 100 ng/mL IGF-1 treatment group. (2) In the vitrified-warmed groups, the rates of cleavage and blastocyst were also highest in the 100 ng/mL IGF-1 treatment group (81.04 ± 1.06%% and 32.16 ± 1.01%), which were close to the rates observed in groups without vitrification (83.25 ± 0.85% and 32.54 ± 0.34%). The rates of cleavage and blastocyst in the other vitrified-warmed groups were 70.92 ± 1.32% and 27.33 ± 1.31% (0 ng/mL); 72.73 ± 0.74% and 29.41 ± 0.84% (50 ng/mL); 72.43 ± 0.61% and 27.61 ± 0.59% (200 ng/mL), respectively. There was no significant difference in the total cell number per blastocysts between the vitrified-warmed groups and group without vitrification. Thus, we conclude that the enhancement in developmental competence of mature yak vitrified-warmed oocytes after the addition of IGF-1 during IVM might result from the regulation of CIRP expression in mature yak oocytes prior to vitrification.
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Affiliation(s)
- Yangyang Pan
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Yan Cui
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Honghong He
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Abdul Rasheed Baloch
- University of South Bohemia in České Budějovice, Faculty of Fisheries and Protection of Waters, South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Zátiší 728/II, 389 25 Vodňany, Czech Republic
| | - Jiangfeng Fan
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Gengquan Xu
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Junfeng He
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Kun Yang
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Guyue Li
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China
| | - Sijiu Yu
- Gansu Province Livestock Embryo Engineering Research Center, College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, China.
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Chian RC, Wang Y, Li YR. Oocyte vitrification: advances, progress and future goals. J Assist Reprod Genet 2014; 31:411-20. [PMID: 24477781 DOI: 10.1007/s10815-014-0180-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/17/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Recent advances in vitrification technology have markedly improved the efficacy of oocyte cryopreservation in terms of oocyte survival and pregnancy, as well as live birth rates. However, there still remains room for improvement in terms of vitrification techniques. OBJECTIVE The remaining challenges include the development of a less cytotoxic vitrification solution and of a safe vitrification device in order to have vitrification techniques considered as a standard clinical laboratory procedure. METHODS A systematic electronic literature search strategy has been conducted using PubMed (Medline) databases with the use of the following key words: oocyte, vitrification, cryoprotectant, preservation, pregnancy, and live birth. A list of published papers focused on the improvement of vitrification techniques to have the vitrification protocol standardized have been evaluated in full text for this review. Only key references were cited. CONCLUSIONS Vitrification technology has made significant advancements and holds great promise, but many issues remains to be addressed before it becomes a standardized procedure in clinical laboratories such as the fact that oocyte vitrification may not require a high concentration of cryoprotectant in the vitrification solution when it has a suitable cooling and warming rate. There is also no consistent evidence that indicates the absence of risk to the vitrified oocytes when they are stored for a prolonged period of time in direct-contact with liquid nitrogen. The long-term development of infants born as a result of this technology equally remains to be evaluated.
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Affiliation(s)
- Ri-Cheng Chian
- Division of Research, Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada,
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