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Zhang Z, Mu Y, Ding D, Zou W, Li X, Chen B, Leung PC, Chang HM, Zhu Q, Wang K, Xue R, Xu Y, Zou H, Zhou P, Wei Z, Cao Y. Melatonin improves the effect of cryopreservation on human oocytes by suppressing oxidative stress and maintaining the permeability of the oolemma. J Pineal Res 2021; 70:e12707. [PMID: 33274466 DOI: 10.1111/jpi.12707] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/17/2020] [Accepted: 11/27/2020] [Indexed: 12/13/2022]
Abstract
Cryopreservation causes cryoinjury to oocytes and impairs their developmental competence. Melatonin (MLT) can improve the effect of cryopreservation in animal oocytes. However, no such studies on human oocytes have been reported. In this study, collected in vitro-matured human oocytes were randomly divided into the following groups: fresh group, MLT-treated cryopreservation (MC) group, and no-MLT-treated cryopreservation (NC) group. After vitrification and warming, viable oocytes from these three groups were assessed for their mitochondrial function, ultrastructure, permeability of oolemma, early apoptosis, developmental competence, and cryotolerance-related gene expression. First, fluorescence staining results revealed that oocytes from the 10-9 M subgroup showed the lowest intracellular reactive oxygen species and Ca2+ levels and highest mitochondrial membrane potential among the MC subgroups (10-11 , 10-9 , 10-7 , and 10-5 M). In subsequent experiments, oocytes from the 10-9 M-MC group were observed to maintain the normal ultrastructural features and the permeability of the oolemma. Compared with those of the oocytes in the NC group, the early apoptosis rate significantly decreased (P < .01), whereas both the high-quality cleavage embryo and blastocyst rates significantly increased (both P < .05) in the oocytes of the 10-9 M-MC group. Finally, single-cell RNA sequencing and immunofluorescence results revealed that aquaporin (AQP) 1/2/11 gene expression and AQP1 protein expression were upregulated in the MC group. Therefore, these results suggest that MLT can improve the effect of cryopreservation on human oocytes by suppressing oxidative stress and maintaining the permeability of the oolemma.
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Affiliation(s)
- Zhiguo Zhang
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
- Department of Biomedical Engineering, Anhui Medical University, Hefei, China
| | - Yaoqin Mu
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
| | - Ding Ding
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
| | - Weiwei Zou
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
| | - Xinyuan Li
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui, China
- Biopreservation and Artificial Organs, Anhui Provincial Engineering Research Center, Anhui Medical University, Anhui, China
| | - Beili Chen
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui, China
- Biopreservation and Artificial Organs, Anhui Provincial Engineering Research Center, Anhui Medical University, Anhui, China
| | - Peter Ck Leung
- Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Hsun-Ming Chang
- Department of Obstetrics and Gynaecology, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Qi Zhu
- Department of Biomedical Engineering, Anhui Medical University, Hefei, China
| | - Kaijuan Wang
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui, China
- Biopreservation and Artificial Organs, Anhui Provincial Engineering Research Center, Anhui Medical University, Anhui, China
| | - Rufeng Xue
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui, China
- Biopreservation and Artificial Organs, Anhui Provincial Engineering Research Center, Anhui Medical University, Anhui, China
| | - Yuping Xu
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- Anhui Province Key Laboratory of Reproductive Health and Genetics, Anhui, China
- Biopreservation and Artificial Organs, Anhui Provincial Engineering Research Center, Anhui Medical University, Anhui, China
| | - Huijuan Zou
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
| | - Ping Zhou
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
| | - Zhaolian Wei
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
| | - Yunxia Cao
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, the First Affiliated Hospital of Anhui Medical University, Anhui, China
- NHC Key Laboratory of study on abnormal gametes and reproductive tract (Anhui Medical University), Anhui, China
- Key Laboratory of Population Health Across Life Cycle (Anhui Medical University), Ministry of Education of the People's Republic of China, Anhui, China
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Swain JE. Controversies in ART: can the IVF laboratory influence preimplantation embryo aneuploidy? Reprod Biomed Online 2019; 39:599-607. [DOI: 10.1016/j.rbmo.2019.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/17/2019] [Accepted: 06/19/2019] [Indexed: 01/08/2023]
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Noyes N, Boldt J, Nagy ZP. Oocyte cryopreservation: is it time to remove its experimental label? J Assist Reprod Genet 2010; 27:69-74. [PMID: 20140641 PMCID: PMC2842870 DOI: 10.1007/s10815-009-9382-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 12/22/2009] [Indexed: 11/25/2022] Open
Abstract
As more reproductive-age women survive cancer at the expense of gonadotoxic therapy, the need for viable fertility preservation options has become paramount. Embryo cryopreservation, often using donor sperm, has been the standard offered these women over the past 20 years. Preservation of unfertilized oocytes now represents an acceptable and often equally viable alternative, particularly for single women, due to technologic advances made in the past decade. Given such, oocyte cryopreservation's experimental designation and need for IRB approval should thus be revisited.
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Affiliation(s)
- Nicole Noyes
- NYU Fertility Center, NYU School of Medicine, New York, NY 10016, USA.
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Noyes N, Porcu E, Borini A. Over 900 oocyte cryopreservation babies born with no apparent increase in congenital anomalies. Reprod Biomed Online 2009; 18:769-76. [PMID: 19490780 DOI: 10.1016/s1472-6483(10)60025-9] [Citation(s) in RCA: 299] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Over the past decade, the number of reported live births resulting from oocyte cryopreservation has rapidly increased. To appreciate the true number of children born, verified live births were tabulated and assessed. A literature search was performed; authors were then contacted to verify birth outcomes and provide updates. A database including all verified live born infants was constructed. A total of 58 reports (1986-2008) were reviewed, which included 609 live born babies (308 from slow freezing, 289 from vitrification and 12 from both methods). Additionally, 327 other live births were verified. Of the total 936 live borns, 1.3% (12) were noted to have birth anomalies: three ventricular septal defects, one choanal and one biliary atresia, one Rubinstein-Taybi syndrome, one Arnold-Chiari syndrome, one cleft palate, three clubfoot and one skin haemangioma. Compared with congenital anomalies occurring in naturally conceived infants, no difference was noted. With more live born data accumulating, this procedure may become mainstream as a fertility preservation option, particularly for women diagnosed with malignancy requiring cytotoxic therapy. A registry would help to assure the safest, most expeditious development of this technology.
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Affiliation(s)
- N Noyes
- Department of Obstetrics and Gynecology, NYU Fertility Center, NYU School of Medicine, New York 10016, USA.
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Mullen SF, Li M, Li Y, Chen ZJ, Critser JK. Human oocyte vitrification: the permeability of metaphase II oocytes to water and ethylene glycol and the appliance toward vitrification. Fertil Steril 2008; 89:1812-25. [PMID: 17681308 PMCID: PMC2494737 DOI: 10.1016/j.fertnstert.2007.06.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 06/06/2007] [Accepted: 06/06/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To determine the permeability of human metaphase II oocytes to ethylene glycol and water in the presence of ethylene glycol, and to use this information to develop a method to vitrify human oocytes. DESIGN An incomplete randomized block design. SETTING A university-affiliated assisted reproductive center. PATIENT(S) Women undergoing assisted reproduction in the Center for Reproductive Medicine at Shandong University. INTERVENTION(S) Oocytes were exposed to 1.0 molar ethylene glycol in a single step and photographed during subsequent volume excursions. MAIN OUTCOME MEASURE(S) A two-parameter model was employed to estimate the permeability to water and ethylene glycol. RESULT(S) Water permeability ranged from 0.15 to 1.17 microm/(min.atm), and ethylene glycol permeability ranged from 1.5 to 30 microm/min between 7 degrees C at 36 degrees C. The activation energies for water and ethylene glycol permeability were 14.42 Kcal/mol and 21.20 Kcal/mol, respectively. CONCLUSION(S) Despite the lower permeability of human metaphase II oocytes to ethylene glycol compared with previously published values for propylene glycol and dimethylsulfoxide, methods to add and remove human oocytes with a vitrifiable concentration of ethylene glycol can be designed that prevent excessive osmotic stress and minimize exposure to high concentrations of this compound.
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Affiliation(s)
- Steven F. Mullen
- The Comparative Medicine Center and Department of Veterinary Pathobiology, The University of Missouri at Columbia, Columbia, MO 65211, USA
| | - Mei Li
- The Reproductive Medical Center of Shandong Provincial Hospital, Shandong University, Jinan, Shandong Province 250021, China
| | - Yuan Li
- The Reproductive Medical Center of Shandong Provincial Hospital, Shandong University, Jinan, Shandong Province 250021, China
| | - Zi-Jiang Chen
- The Reproductive Medical Center of Shandong Provincial Hospital, Shandong University, Jinan, Shandong Province 250021, China
- The Department of Medical Microbiology and Immunology, The University of Missouri at Columbia, Columbia, MO 65211, USA
| | - John K. Critser
- The Comparative Medicine Center and Department of Veterinary Pathobiology, The University of Missouri at Columbia, Columbia, MO 65211, USA
- The Reproductive Medical Center of Shandong Provincial Hospital, Shandong University, Jinan, Shandong Province 250021, China
- The Department of Medical Microbiology and Immunology, The University of Missouri at Columbia, Columbia, MO 65211, USA
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Abstract
The clinical role of oocyte cryopreservation in assisted reproduction, as an adjunct to sperm and embryo cryopreservation, has been comparatively slow to evolve as a consequence of theoretical concerns related to efficacy and safety. Basic biological studies in the 1990's alleviated many of these concerns leading to more widespread adoption of the technology. While a number of babies were born from the approach validated in the 1990's, its perceived clinical inefficiency led to the search for improved methods. Introduction of elevated dehydrating sucrose concentrations during cryopreservation increased survival and fertilization rates, but there is no well-controlled evidence of improved clinical outcome. Similarly, the use of sodium-depleted cryopreservation media has not been demonstrated to increase clinical efficiency. More recently, and in the absence of basic biological studies addressing safety issues, the application of vitrification techniques to human oocytes has resulted in reports of a number of live births. The small number of babies born from clinical oocyte cryopreservation and the paucity of well-controlled studies currently preclude valid comparisons between approaches. Legal restrictions on the ability to select embryos from cryopreserved oocytes in Italy, where many of the available reports originate, also obscure attempts to assess oocyte cryopreservation objectively.
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Affiliation(s)
- Debra A Gook
- Reproductive Services/Melbourne IVF, Royal Women's Hospital, 132 Grattan Street, Carlton, Victoria 3053, and Department of Obstetrics and Gynaecology, University of Melbourne, Australia.
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Jain JK, Paulson RJ. Oocyte cryopreservation. Fertil Steril 2006; 86:1037-46. [PMID: 17008147 DOI: 10.1016/j.fertnstert.2006.07.1478] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2006] [Revised: 07/29/2006] [Accepted: 07/29/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To review historical and contemporary advances in oocyte-cryopreservation techniques and outcomes. DESIGN Publications related to oocyte cryopreservation were identified through MEDLINE and other bibliographic databases. CONCLUSION(S) Oocyte cryopreservation can be used as an adjunct to conventional IVF and as an option for fertile women to electively cryopreserve their gametes. Recent reports indicate pregnancy rates comparable to those for cryopreserved embryos by either slow-freeze or vitrification methods. Larger prospective trials are needed to determine the true efficacy and safety of oocyte cryopreservation. Until a sufficient number of births is reached and adequate outcome data are collected, oocyte cryopreservation should continue to be considered experimental and to be performed under the oversight of an institutional review board.
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Affiliation(s)
- John K Jain
- Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, University of Southern California Keck School of Medicine, Los Angeles, California 90033, USA.
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Fabbri R. Cryopreservation of Human Oocytes and Ovarian Tissue. Cell Tissue Bank 2006; 7:113-22. [PMID: 16732414 DOI: 10.1007/s10561-005-1969-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2005] [Accepted: 08/10/2005] [Indexed: 10/24/2022]
Abstract
Oocyte cryopreservation has the potential to be an important adjunct to assisted reproductive technologies and bypasses some ethical, moral, and religious dilemmas posed by human embryo cryopreservation. The success of human oocyte cryopreservation depends on morphological and biophysical factors that could influence oocyte survival after thawing. Among the morphological factors, the maturity, quality, size of the oocyte, the presence or the absence of the cumulus oophorus seems to play an important role in oocyte survival after thawing. The main biophysical factor of cellular disruption during cryopreservation process in the intracellular ice formation that can be avoided by an adequate cell dehydration; thus reducing the intracellular water by increasing the dehydration process we can limit the damages of the cryopreservation procedure. The dehydration process can be affected by the presence and concentration of the cryoprotectants in the freezing solutions (equilibration and loading solutions), and by the freezing and thawing rate. Two additional properties of cryoprotectants help to protect cells during slow cooling, when the cells are very dehydrated and are surrounded by concentrated salts. The cryoprotectants appear to reduce damage caused by high levels of salt, a property known as salt buffering. Some events occurring to the oocyte during cryopreservation procedure has been found to be a premature exocitosis of cortical granules, leading to an intempestive zona hardening and consequently to a reduction of fertilization rate, and the cryoinjury to the zona pellucida leading to a polispermic fertilization. ICSI is an efficient method to by pass these two events and to achieve a satisfactory outcome in terms of normal fertilization of cryopreserved oocytes. The application of the ICSI to cryopreserved oocytes did not seem to increase the degeneration rate after insemination with respect to fresh oocytes. The increased oocyte survival rate and the use of ICSI have facilitated the recent increase in the number of pregnancies and live birth.
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Affiliation(s)
- Raffaella Fabbri
- Human Reproduction Medicine Unit, S. Orsola-Malpighi Hospital, University of Bologna, Italy.
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Koutlaki N, Schoepper B, Maroulis G, Diedrich K, Al-Hasani S. Human oocyte cryopreservation: past, present and future. Reprod Biomed Online 2006; 13:427-36. [PMID: 16984778 DOI: 10.1016/s1472-6483(10)61449-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Despite inferior results in the past compared with embryo freezing, oocyte cryopreservation has made great strides in recent years. In fact, it has become a necessity in assisted reproduction technology, providing alternatives to legal, moral and religious problems originating from embryo freezing. Recent advances in freezing technology, modifications of conventional protocols used and continuing optimization of vitrification have efficiently improved the method. A historical description of the method's progression over time, and a comparison of principles, procedures and results as reported in the literature are presented in this review.
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Affiliation(s)
- N Koutlaki
- Department of Obstetrics and Gynecology, University of Schleswig-Holstein, Luebeck, Germany
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Fabbri R, Porcu E, Marsella T, Primavera MR, Rocchetta G, Ciotti PM, Magrini O, Seracchioli R, Venturoli S, Flamigni C. Technical aspects of oocyte cryopreservation. Mol Cell Endocrinol 2000; 169:39-42. [PMID: 11155952 DOI: 10.1016/s0303-7207(00)00349-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the successful development in the mouse, the oocyte cryopreservation has been applied with varying success to a number of different species including the human. The recently reported successes in terms of pregnancies obtained by human oocyte cryopreservation are encouraging. Several studies typically reported different rates of survival (20-80%), fertilization (30-60%) and cleavage (32-100%). This variability of results throws some doubts on the usefulness of oocyte cryopreservation in IVF treatment cycles. It remains to be determined whether the relatively different success rates reported in literature, mainly in terms of survival rate, are due to methodological differences. We tried to investigate the effect of some factors on the oocyte survival rate after thawing: the presence or absence of cumulus oophorus and the exposure time of the oocytes to cryoprotectant. We suggest that a combination of several factors including both morphological and biophisical ones can affect the oocyte survival rate.
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Affiliation(s)
- R Fabbri
- IVF Center, Human Reproductive Medicine Unit, Institute Obstetrics and Gynecology, Bologna, Italy.
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Wu B, Tong J, Leibo SP. Effects of cooling germinal vesicle-stage bovine oocytes on meiotic spindle formation following in vitro maturation. Mol Reprod Dev 1999; 54:388-95. [PMID: 10542379 DOI: 10.1002/(sici)1098-2795(199912)54:4<388::aid-mrd9>3.0.co;2-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Attempts to cryopreserve bovine oocytes result in low survival because of their sensitivity to temperatures near 0 degrees C. This study evaluates the effects of chilling germinal vesicle-stage (GV) oocytes on their formation of microtubules and the meiotic spindle. In experiment 1, five groups of GV-stage oocytes, each consisting of approximately 90 oocytes, were held at 39 degrees C as controls, or at 31 degrees C, or cooled to 24, 4 or 0 degrees C for 10 min. After being treated, all oocytes were cultured at 39 degrees C for 24 hr. Compared to the controls, holding oocytes for 10 min at 31 or 24 degrees C did not significantly alter the formation of normal spindles, but chilling them to 4 or 0 degrees C did. After 24 hr of maturation, the respective percentages of oocytes containing normal meiotic spindles observed in the controls or those held at 31 or 24 degrees C were 69.8%, 71.9%, or 69.4% (P > 0.05). In contrast, the percentages of oocytes with normal spindles after they had been cooled to 4 or 0 degrees C were 44.0% or 29.1%, respectively. In experiment 2, approximately 90 oocytes/group were cooled to 4 degrees C for various times before being warmed and cultured. Regardless of the time of exposure, cooling oocytes to 4 degrees C reduced the formation of normal spindles. The percentages of oocytes cooled to 4 degrees C for 10, 20, 30, 45, or 60 min with normal spindles were 44.0%, 38.4%, 37.5%, 34.5% and 30.9%, respectively. In experiment 3, approximately 60 oocytes per group that had been held at 31 degrees C or cooled to 24, 4 or 0 degrees C for 10 min were allowed to mature for 24 hr before being subjected to in vitro fertilization. The cleavage rates of oocytes subjected to various chilling treatments exhibited the same pattern as that of oocytes with normal spindles. That is, there were no significant differences in cleavage rates among the control oocytes and those held at 31 or 24 degrees C (70.4%, 71.8%, and 72.4%; P > 0.05). However, only 37. 0% and 30.4% of oocytes chilled to 4 or 0 degrees C cleaved after fertilization. These results suggest that: (1) chilling bovine oocytes no lower than 24 degrees C does not reduce formation of normal meiotic spindles; (2) however, chilling oocytes to 4 degrees C or lower for as little as 10 min drastically reduces the formation of normal meiotic spindles and of fertilization; (3) the rates of fertilization and cleavage of resultant zygotes mimic that of formation of normal spindles.
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Affiliation(s)
- B Wu
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Canada.
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Trad FS, Toner M, Biggers JD. Effects of cryoprotectants and ice-seeding temperature on intracellular freezing and survival of human oocytes. Hum Reprod 1999; 14:1569-77. [PMID: 10357978 DOI: 10.1093/humrep/14.6.1569] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The accurate determination of the freezing conditions that promote intracellular ice formation (IIF) is crucial for designing cryopreservation protocols for cells. In this paper, the range of temperatures at which IIF occurs in human oocytes was determined. Fresh oocytes with a germinal vesicle, failed-to-fertilize (metaphase I and metaphase II stages) and polyspermic eggs were used for this study. The occurrence of IIF was first visualized at a cooling rate of 120 degrees C/min using a programmable thermal microscope stage connected to a videomicroscope. Then, with a cooling rate of 0.2 degrees C/min, the seeding temperature of the extracellular ice was modified to decrease the incidence of IIF and increase the survival rate of frozen-thawed human oocytes. After adding different cryoprotectants, the median temperature of IIF (TMED) was decreased by approximately 23 degrees C in mouse and only by approximately 6.5 degrees C in human oocytes. Using 1.5 M propylene glycol and seeding temperatures of -8.0, -6.0 and -4.5 degrees C, the incidence of IIF was 22/28 (78%), 8/24 (33%) and 0/33 (0%) and the 24 h post-thaw survival rate was 10/31(32%), 19/34 (56%) and 52/56 (93%) respectively. The results show that IIF occurs more readily in human oocytes, and that ice seeding between -6 degrees C and -8 degrees C triggers IIF in a large number of human oocytes. Undesirable IIF can be prevented and survival rates maximized by raising the seeding temperature as close as possible to the melting point of the solution, which in our instrument was -4.5 degrees C.
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Affiliation(s)
- F S Trad
- Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA 02115, USA
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Abstract
The scientific advances of human genetics and assisted reproductive technology are redefining the concepts of health and illness by revealing the mysteries of the human genome and the process of conception, implantation, and diagnostic testing of the human embryo. The effect of these discoveries and their clinical applications will move from the tertiary to primary care arena through the ability to readily screen, diagnose, and treat some disorders and offer cure as the end result for others. In addition, the ethical, legal, and social issues, along with the attendant implications for professional practice, will need to be identified. Only a small portion of nurses have had to address the knowledge and practice issues associated with these advances. "Brave new families" are being created. Perinatal nurses must be prepared to meet the emerging needs of these families through the art and science of nursing.
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Affiliation(s)
- S L Jones
- Department of Nursing, Genetics & IVF Institute, Fairfax, Virginia
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