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Media optimization to promote rat embryonic development to the blastocyst stage in vitro. Theriogenology 2020; 151:81-85. [PMID: 32311604 DOI: 10.1016/j.theriogenology.2020.03.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 03/03/2020] [Accepted: 03/08/2020] [Indexed: 11/21/2022]
Abstract
Efficient model production in rats that incorporates newly developed genetic editing and embryo transfer tools, such as CRISPR/Cas9 technology and non-surgical embryo transfer, requires availability of an optimal embryo culture system. However, current technologies for in vitro manipulation of rat gametes, including embryo culture techniques, are less advanced compared to those in mice. In this study, we (1) identified a culture medium that was able to support optimal rat embryonic development by comparing two rat culture media: mR1ECM (modified rat 1-cell embryo culture medium) and KSOM-R (modified potassium simplex optimized medium for rats), and (2) evaluated the effect of glutamine dipeptides: alanyl-l-glutamine and glycyl-l-glutamine, on rat embryonic development. We also investigated the possibility of simplifying the KSOM-R culture procedure by increasing the volume of culture medium, reducing the need for daily medium changes. The results showed that rat embryos cultured in KSOM-R developed faster than those cultured in mR1ECM. Both alanyl-l-glutamine and glycyl-l-glutamine showed detrimental effects on rat embryonic development when supplemented in KSOM-R at the same concentration as glutamine. By increasing the volume of KSOM-R, rat zygotes were able to develop without daily medium refreshment at a similar rate and developmental competence as those in smaller volumes with daily medium changes. These results represent important improvements to rat embryo culture methods and will assist in more efficient production of rat models.
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Abstract
The rat is one the most widely used laboratory animal species in many aspects of biomedical research, including the production of genetically engineered animal models to study human diseases and conditions. In addition to in vitro fertilization (IVF), the ability to grow IVF-derived or in vivo-collected zygotes to a desired preimplantation stage (zygote to blastocyst) entirely in vitro has a great importance for studies of developmental biology and genetic modification of laboratory rats for biomedical research. Although embryo biotechnologies are required to study or manipulate the genome effectively, such technologies for rat preimplantation embryos are not currently as successful as they are in the mouse. Here we provide a brief history of the development of rat in vitro culture systems and a step-by-step protocol to produce rat blastocyst stage embryos from zygotes under in vitro conditions from commonly used laboratory rat strains in biomedical research.
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Affiliation(s)
- Yuksel Agca
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA.
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Molecular and ultrastuctural changes of rat pre-implantation embryos during two-cell developmental arrest. J Assist Reprod Genet 2015; 31:767-80. [PMID: 24658924 DOI: 10.1007/s10815-014-0213-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 03/04/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Rat pre-implantation embryos often suffer 2-cell stage developmental arrest and fail to progress further under in-vitro conditions. OBJECTIVE In order to understand underlying mechanism leading to 2-cell arrest, we investigated the molecular changes, culture conditions and subcellular changes. METHODS Gene expression in in-vivo developed 2-cell embryos (in-vivo), in- vitro developed 2-cell embryos (in-vitro), and in-vitro 2-cell arrested embryos (arrested) were investigated using microarrays and real-time PCR. Ultra-structural changes were determined using electron microscopy. RESULTS Gene expression was similar between in-vivo and in-vitro embryos. Over 2400 genes changed in arrested embryos compared to in-vivo and in-vitro embryos. The mRNAs encoding proteins involved in translation were elevated in arrested embryos. In-vivo and in-vitro embryos highly expressed genes that were involved in cell cycle, and protein catabolic process compared to arrested embryos. Gene expression data suggested subcellular changes associated with 2-cell block. Transmission electron microscopy showed that in-vivo embryos had healthy subcellular structure, whereas arrested embryos did not have a nuclear membrane, contained small mitochondria and autophagic vacuoles. Furthermore, gene expression data was used for the optimization of culture media conditions to obtain better in-vitro embryonic development. Comparison of five and 20 % oxygen in culture resulted in two times more blastocyst formation with 5 % oxygen. CONCLUSIONS These results showed that although all experimental groups appeared morphologically similar, arrested embryos had ultra-structural and molecular changes associated with oxidative stress and apoptosis. In-vitro culture under low oxygen and media additives reduced 2-cell block in rat embryos.
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FUJIWARA K, SANO D, SEITA Y, INOMATA T, ITO J, KASHIWAZAKI N. Ethylene Glycol-supplemented Calcium-free Media Improve Zona Penetration of Vitrified Rat Oocytes by Sperm Cells. J Reprod Dev 2010; 56:169-75. [DOI: 10.1262/jrd.09-107h] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Katsuyoshi FUJIWARA
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University
| | - Daisuke SANO
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University
| | - Yasunari SEITA
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University
- Department of Obstetrics, Gynecology and Reproductive Science, Human Embryonic Stem Cell Core Facility, UMDNJ-Robert Wood Johnson Medical School
| | - Tomo INOMATA
- Laboratory of Experimental Animal Science, Graduate School of Veterinary Science, Azabu University
- School of Veterinary Medicine, Azabu University
| | - Junya ITO
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University
- School of Veterinary Medicine, Azabu University
| | - Naomi KASHIWAZAKI
- Laboratory of Animal Reproduction, Graduate School of Veterinary Science, Azabu University
- School of Veterinary Medicine, Azabu University
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Importance of primary culture conditions for the development of rat ICSI embryos and long-term preservation of freeze-dried sperm. Cryobiology 2009; 58:293-7. [PMID: 19236858 DOI: 10.1016/j.cryobiol.2009.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 02/06/2009] [Accepted: 02/12/2009] [Indexed: 11/23/2022]
Abstract
Rat sperm freeze-dried in a solution containing Tris and ethylenediaminetetraacetic acid (EDTA) (TE buffer) can be preserved at 4 degrees C, and oocytes injected with these sperm developed into offspring though developmental ability was low. We studied the culture conditions to improve the developmental ability of oocytes injected with freeze-dried sperm. After being injected with fresh sperm, the zygotes were cultured in modified Krebs-Ringer bicarbonate (mKRB), modified rat 1-cell embryo culture medium (mR1ECM)/BSA, and mR1ECM with different osmolality, before being cultured in mR1ECM. High proportion of zygotes cultured in mKRB (270mOsm) before being cultured in mR1ECM developed into blastocysts compared to zygotes cultured only with mR1ECM (50% vs. 28%, P<0.05). Culturing in mKRB also led to a high proportion of zygotes developing into blastocysts after the injection of freeze-dried sperm than zygotes cultured only with mR1ECM (32% vs. 15%, P<0.05). Offspring (16%) were obtained when 19 2-cell embryos derived from oocytes that had been injected with freeze-dried sperm preserved at 4 degrees C for 1year were transferred. This study demonstrated that the culture conditions soon after the injection of sperm markedly influenced the subsequent development of embryos. Also, rat sperm after freeze-drying in TE buffer were preserved at 4 degrees C for long term without their deterioration.
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Han MS, Niwa K. Effects of BSA and fetal bovine serum in culture medium on development of rat embryos. J Reprod Dev 2006; 49:235-42. [PMID: 14967933 DOI: 10.1262/jrd.49.235] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rat 1-cell embryos, recovered from naturally mated females, were cultured in a chemically defined medium (mR1ECM) or in mR1ECM supplemented with BSA (4 mg/ml; mR1ECM-BSA) or fetal bovine serum (FBS; 10%, v:v; mR1ECM-FBS) instead of polyvinylalcohol. There was no difference in percentages of embryos that developed to the 2-cell to blastocyst stages between mR1ECM and mR1ECM-BSA, but in mR1ECM-FBS, no development beyond the 2-cell stage was observed. When embryos were transferred to mR1ECM-FBS from mR1ECM after 24 to 64 h of culture, development of embryos to and beyond the 4-cell stage was inhibited. However, when transferred after 80 h of culture, more embryos developed to blastocysts and hatching or hatched blastocysts than in embryos cultured in mR1ECM. When 8-cell embryos and early morulae obtained after 72 and 80 h of culture in mR1ECM, respectively, were cultured in mR1ECM-FBS, a higher proportion of early morulae developed to the blastocyst stage than did 8-cell embryos. When morulae obtained after culture in mR1ECM or mR1ECM-BSA were transferred to recipient females, there was no difference in proportions of fetuses obtained. However, a higher proportion of blastocysts cultured in mR1ECM-FBS developed to fetuses compared with those obtained in mR1ECM. These results indicate that BSA has neither deleterious nor beneficial effects on development of rat 1-cell embryos. In contrast, FBS has deleterious effects on early cleavage of embryos but it promotes more rapid development of morulae to blastocysts, resulting in better quality blastocysts.
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Affiliation(s)
- Myung-Sook Han
- The Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
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Zhou Y, Galat V, Garton R, Taborn G, Niwa K, Iannaccone P. Two-phase chemically defined culture system for preimplantation rat embryos. Genesis 2003; 36:129-33. [PMID: 12872243 DOI: 10.1002/gene.10203] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A limiting factor in the development of new technologies and transport of rats worldwide has been the inability to robustly culture preimplantation embryos. Previously, culture in vitro to the blastocyst stage from one-cell embryos was successful only if the one-cell embryos were isolated near the time of the first cleavage and from only a few strains. Here we report the use of commonly available, chemically defined culture media to overcome these limitations. In vitro culture of young one-cell embryos using common embryo media (KSOM, BMOC, or HTF) for 18-22 h followed by culture in mR1ECM medium allows the successful in vitro development of blastocysts from one-cell embryos after 5 days from both outbred (SD) and inbred strains of rat (WF, LEW, F344, and PVG). This system allows the parthenogenetic development of chemically activated, unfertilized oocytes to the blastocyst stage. Embryos cultured in this system develop to term and are live-born following transfer to surrogate mothers.
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Krivokharchenko A, Galat V, Ganten D, Bader M. In vitro formation of tetraploid rat blastocysts after fusion of two-cell embryos. Mol Reprod Dev 2002; 61:460-5. [PMID: 11891917 DOI: 10.1002/mrd.90001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Gene targeting technology is not available in the rat which is an animal model of major importance, e.g., in cardiovascular research. This is due to the fact that the rat embryonic stem cell (ESC)-like cells established by several groups do not form germ-line chimeras when injected into blastocysts. In the mouse, the aggregation of ESC with tetraploid embryos has allowed the generation of animals completely derived from these cells. However, aggregation of rat ESC-like cells with tetraploid rat embryos has not yet been attempted to evaluate their developmental capacity. Therefore, we established a method to produce tetraploid rat embryos by fusion at the two-cell stage. Chemical fusion by polyethylene glycol (PEG) was shown to be less efficient (56.3% fused embryos) than electrofusion (96.1% fused embryos). The rate of development of fused embryos to blastocysts was independent of the fusion method and similar to the rate of control embryos. However, this rate was lower when the embryos had been cultured from the zygote state before fusion (14-20%) compared to freshly isolated two-cell embryos (41-63%). Alike for the mouse, blastocysts derived from fused two-cell rat embryos contained about half the number of cells as control blastocysts and were homogeneously tetraploid with no evidence of mosaicism. This method may be useful for the establishment of gene-targeting technology in the rat.
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Biggers JD, McGinnis LK. Evidence that glucose is not always an inhibitor of mouse preimplantation development in vitro. Hum Reprod 2001; 16:153-163. [PMID: 11139555 DOI: 10.1093/humrep/16.1.153] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A factorial experimental design was used to examine the effects of 16 combinations of four concentrations of glucose (0.20, 0.60, 1.8, 5.4 mmol/l) and four concentrations of potassium dihydrogen phosphate (KH(2)PO(4); 0.05, 0.15, 0.45, 1.35 mmol/l) on the development in vitro of outbred CF1 mouse zygotes. Three responses were measured: (i) the number of zona-enclosed blastocysts; (ii) the number of blastocysts that started to hatch; and (iii) the total cell counts in the blastocysts. General linear modelling was used to estimate the most parsimonious two-dimensional concentration-response surfaces that represent the three responses to the different concentrations of glucose and KH(2)PO(4). There were no significant interactions between the effects of glucose and KH(2)PO(4) in all cases. Thus, the effects of glucose and phosphate are independent. No significant effects of glucose on blastocyst formation and the initiation of hatching were observed. Increasing the concentration of KH(2)PO(4) inhibited slightly (</=20%) the development of zygotes into blastocysts and the initiation of hatching. The slight inhibitory effects of KH(2)PO(4) appeared to be due to the inhibition of the development of a few sensitive embryos. No significant effects of glucose and KH(2)PO(4) were observed on the total cell counts.
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Affiliation(s)
- J D Biggers
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
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Goh VH, Adiga SK, Tain CF, Tong TY, Ng SC. Successful in vitro growth of rat two-cell embryos to blastocysts using a simple chemically defined medium. J Pharmacol Toxicol Methods 2000; 43:171-5. [PMID: 11257480 DOI: 10.1016/s1056-8719(00)00084-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of the present study was to formulate a simple chemically defined medium for the in vitro growth of rat two-cell embryos to blastocysts. Embryos from day 2 pregnant rats were retrieved and placed in paraffin oil-covered droplets of "rat two-cell embryo culture medium" (R2ECM) containing combinations of various serum supplements, glucose, L-glutamine, and cultured up to 96 h in a CO(2) incubator. Embryos cultured in the basic medium (R2ECM), as well as those supplemented either with fetal bovine serum (FBS) or male rat serum (MRS) did not develop beyond the two- to four-cell stage. In R2ECM with 0.3% bovine serum albumin (BSA) and 7.5 mM glucose, 44% of embryos reached the blastocyst stage by 96 h in culture, and the blastulation rate increased to about 83% when 1 mM of L-glutamine was added. To evaluate the effects of varying doses of glucose, two-cell embryos were cultured in R2ECM supplemented with 0.3% BSA, 1 mM L-glutamine, and 2.5, 5.0, or 7.5 mM of glucose. The percentage of embryos reaching the blastocyst stage for 2.5, 5.0, and 7.5 mM glucose was 64.6%, 65.3%, and 82.9%, respectively. The present study showed that the modified medium (R2ECM) is a simple chemically defined medium that is capable of supporting in vitro growth of rat two-cell embryos to blastocysts in high proportion (greater than 80%) without the need for change of medium within 96 h of culture.
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Affiliation(s)
- V H Goh
- Department of Obstetrics and Gynecology, National University Hospital, National University of Singapore, 5 Lower Kent Road, 119074, Singapore, Singapore.
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Fitchev P, Taborn G, Garton R, Iannaccone P. Nuclear transfer in the rat: potential access to the germline. Transplant Proc 1999; 31:1525-30. [PMID: 10330990 DOI: 10.1016/s0041-1345(99)00026-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- P Fitchev
- Department of Pediatrics, Northwestern University Medical School, Children's Memorial Institute for Education and Research, Chicago, IL 60614, USA
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