1
|
Chen PR, Redel BK, Kerns KC, Spate LD, Prather RS. Challenges and Considerations during In Vitro Production of Porcine Embryos. Cells 2021; 10:cells10102770. [PMID: 34685749 PMCID: PMC8535139 DOI: 10.3390/cells10102770] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 02/02/2023] Open
Abstract
Genetically modified pigs have become valuable tools for generating advances in animal agriculture and human medicine. Importantly, in vitro production and manipulation of embryos is an essential step in the process of creating porcine models. As the in vitro environment is still suboptimal, it is imperative to examine the porcine embryo culture system from several angles to identify methods for improvement. Understanding metabolic characteristics of porcine embryos and considering comparisons with other mammalian species is useful for optimizing culture media formulations. Furthermore, stressors arising from the environment and maternal or paternal factors must be taken into consideration to produce healthy embryos in vitro. In this review, we progress stepwise through in vitro oocyte maturation, fertilization, and embryo culture in pigs to assess the status of current culture systems and address points where improvements can be made.
Collapse
Affiliation(s)
- Paula R. Chen
- Division of Animal Sciences, University of Missouri, Columbia, MO 65211, USA
| | | | - Karl C. Kerns
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA
| | - Lee D. Spate
- Division of Animal Sciences, University of Missouri, Columbia, MO 65211, USA
- National Swine Resource and Research Center, University of Missouri, Columbia, MO 65211, USA
| | - Randall S. Prather
- Division of Animal Sciences, University of Missouri, Columbia, MO 65211, USA
- National Swine Resource and Research Center, University of Missouri, Columbia, MO 65211, USA
- Correspondence:
| |
Collapse
|
2
|
Extracellular vesicles of follicular fluid from heat-stressed cows modify the gene expression of in vitro-matured oocytes. Anim Reprod Sci 2019; 205:94-104. [PMID: 31060922 DOI: 10.1016/j.anireprosci.2019.04.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 02/19/2019] [Accepted: 04/22/2019] [Indexed: 12/22/2022]
Abstract
The effect of heat stress (HS) on cattle reproduction is deleterious with respect to ovarian follicular development and oocyte quality. The objective of this study was to investigate the effect of follicular fluid extracellular vesicles (EVs) obtained from cows maintained in thermoneutral (TN) or HS conditions on in vitro oocyte maturation. Nonlactating cows were estrous synchronized. Immediately after ovulation day (D1), the cows were randomly assigned to TN or HS environments. Follicular fluid from all follicles from each treatment was pooled, and EVs were obtained. Pools of 20 cumulus oocyte-complexes (COCs), were allocated to the following treatments: Control (n = 4 COC pools): matured in base medium; TN (n = 4 COC pools): matured in base medium supplemented with TN EV suspension; and HS (n = 4 COC pools): matured in base medium that was supplemented with the HS EV suspension. All treatments were conducted at 38.5 °C for 24 h in a humid atmosphere with 5% CO2. After maturation, the COCs were evaluated for meiotic progression, DNA integrity and oocyte quality-related gene expression. When the experimental groups were compared with the control group, a treatment effect was not observed for meiotic progression and DNA integrity. In the cumulus cells of TN group, there was relatively lesser expression of the IGFBP4 gene. In the oocytes of the TN as compared with the HS group, the IGFBP2, BMP15, GDF9, CDCA8, HAS2, RPL15, STAT3 and PFKP genes were expressed to a lesser extent. The findings indicated that oocytes matured in the presence of EVs from the follicular fluid of cows collected when there were TN conditions, however, there was a lesser expression of genes related to oocyte quality.
Collapse
|
3
|
Boni R. Heat stress, a serious threat to reproductive function in animals and humans. Mol Reprod Dev 2019; 86:1307-1323. [PMID: 30767310 DOI: 10.1002/mrd.23123] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/25/2019] [Accepted: 01/27/2019] [Indexed: 12/18/2022]
Abstract
Global warming represents a major stressful environmental condition that compromises the reproductive efficiency of animals and humans via a rise of body temperature above its physiological homeothermic point (heat stress [HS]). The injuries caused by HS on reproductive function involves both male and female components, fertilization mechanisms as well as the early and late stages of embryo-fetal development. This occurrence causes great economic damage in livestock, and, in wild animals creates selective pressure towards the advantages of better-adapted genotypes to the detriment of others. Humans undergo several types of stress, including heat, and these represent putative causes of ongoing progressive decay in procreation; an increasing number of remedies in the form of antioxidant preparations are now being proposed to counteract the effects of stress. This review aims to describe the results of the most recent studies that aimed to highlight these effects and to draw information on the mechanisms acting as the basis of this problem from a comparative analysis.
Collapse
Affiliation(s)
- Raffaele Boni
- Department of Sciences, University of Basilicata, Potenza, Italy
| |
Collapse
|
4
|
Loren P, Cheuquemán C, Sánchez E, Risopatrón J, Arias ME, Felmer R, Sánchez R. Effect of short-term exposure of cumulus-oocyte complex to 3-morpholinosydnonimine on in vitro embryo development and gene expression in cattle. Reprod Domest Anim 2016; 51:1010-1019. [PMID: 27644683 DOI: 10.1111/rda.12788] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 08/04/2016] [Indexed: 11/28/2022]
Abstract
Short-term exposure of gametes to different types of stress might induce stress tolerance in mammalian embryos. The aim of this study was to evaluate the effect of short-term exposure of bovine mature cumulus-oocyte complex (COC) to 3-morpholinosydnonimine (SIN-1) on subsequent in vitro embryo development, embryo quality and relative gene expression. Matured COCs were incubated with SIN-1 (0, 0.1, 1, 10 and 100 μM SIN-1) for 1 hr before in vitro fertilization and zygotes were cultured until Day 7. The cleavage rate at 72 hr did not show any differences among groups. However, the blastocyst rate on Day 7 decreased with all treatments evaluated, with the embryos generated with 10 μM SIN-1 showing the lowest embryo production rate. Embryo quality analysis did not show any differences in total cell number (TCN) or inner cell mass (ICM) among groups. Relative gene expression analysis showed a downregulation of eNOS expression and an upregulation of nNOS expression in all treatments evaluated compared to the control group. Also, a downregulation was observed in some treatments: SOD2 at 0.1 μM; SOD1 at 0.1 and 100 μM; PRDX5 at 0.1, 10 and 100 μM; and NANOG at 10 and 100 μM; and an upregulation of CDX2 expression was observed at 100 μM. The other genes (OCT4, HIF1A, HSPA1A, BCL2A and iNOS) did not show any differences in the relative gene expression. These results suggest that the short-term exposure of mature bovine COCs to SIN-1 does not induce stress tolerance and has no beneficial effect on bovine in vitro embryo production.
Collapse
Affiliation(s)
- P Loren
- Student of Doctoral Program in Sciences major in Applied Cellular and Molecular Biology, Universidad de la Frontera, Temuco, Chile.,Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile
| | - C Cheuquemán
- Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile
| | - E Sánchez
- Student of Doctoral Program in Sciences major in Applied Cellular and Molecular Biology, Universidad de la Frontera, Temuco, Chile.,Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile
| | - J Risopatrón
- Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile.,Department of Basic Science, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile
| | - M E Arias
- Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile.,Department of Agricultural and Livestock Production, Faculty of Farming, Livestock and Forestry Sciences, Universidad de La Frontera, Temuco, Chile
| | - R Felmer
- Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile.,Department of Agricultural and Livestock Production, Faculty of Farming, Livestock and Forestry Sciences, Universidad de La Frontera, Temuco, Chile
| | - R Sánchez
- Centre of Biotechnology on Reproduction (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile.,Department of Preclinical Sciences, Faculty of Medicine, Universidad de La Frontera, Temuco, Chile
| |
Collapse
|
5
|
Zou C, Fu Y, Li C, Liu H, Li G, Li J, Zhang H, Wu Y, Li C. Genome-wide gene expression and DNA methylation differences in abnormally cloned and normally natural mating piglets. Anim Genet 2016; 47:436-50. [DOI: 10.1111/age.12436] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2016] [Indexed: 01/24/2023]
Affiliation(s)
- C. Zou
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - Y. Fu
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - C. Li
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - H. Liu
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - G. Li
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - J. Li
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - H. Zhang
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - Y. Wu
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| | - C. Li
- Key Lab of Agriculture Animal Genetics, Breeding, and Reproduction of Ministry of Education; College of Animal Science and Technology; Huazhong Agricultural University; Wuhan 430070 People's Republic of China
| |
Collapse
|
6
|
Camargo LSA, Paludo F, Pereira MM, Wohlres-Viana S, Gioso MM, Carvalho BC, Quintao CCR, Viana JHM. Absence of Sperm Factors as in the Parthenogenesis Does Not Interfere on Bovine Embryo Sensitiveness to Heat Shock at Pre-Implantation Stage. Reprod Domest Anim 2015; 51:3-9. [DOI: 10.1111/rda.12637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/09/2015] [Indexed: 11/28/2022]
Affiliation(s)
- LSA Camargo
- Brazilian Agricultural Research Corporation - Embrapa; Juiz de Fora MG Brazil
- UNIFENAS; Alfenas MG Brazil
| | | | - MM Pereira
- Federal University of Juiz de Fora; Juiz de Fora MG Brazil
| | | | | | - BC Carvalho
- Brazilian Agricultural Research Corporation - Embrapa; Juiz de Fora MG Brazil
- UNIFENAS; Alfenas MG Brazil
| | - CCR Quintao
- Brazilian Agricultural Research Corporation - Embrapa; Juiz de Fora MG Brazil
| | - JHM Viana
- Brazilian Agricultural Research Corporation - Embrapa; Juiz de Fora MG Brazil
- UNIFENAS; Alfenas MG Brazil
| |
Collapse
|
7
|
Abazari-Kia AH, Dehghani-Mohammadabadi M, Mohammadi-Sangcheshmeh A, Zhandi M, Salehi M. Regulation of embryonic development and apoptotic-related gene expression by brain-derived neurotrophic factor in two different culture conditions in ovine. Theriogenology 2015; 84:62-9. [DOI: 10.1016/j.theriogenology.2015.02.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/15/2015] [Accepted: 02/09/2015] [Indexed: 02/04/2023]
|
8
|
IVF outcome in women with accidental contamination of follicular fluid with endometrioma content. Eur J Obstet Gynecol Reprod Biol 2014; 181:130-4. [DOI: 10.1016/j.ejogrb.2014.07.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 07/24/2014] [Accepted: 07/29/2014] [Indexed: 11/22/2022]
|
9
|
Abstract
BACKGROUND The advances in the world of IVF during the last decades have been rapid and impressive and culture media play a major role in this success. Until the 1980s fertility centers made their media in house. Nowadays, there are numerous commercially available culture media that contain various components including nutrients, vitamins and growth factors. This review goes through the past, present and future of IVF culture media and explores their composition and quality assessment. METHODS A computerized search was performed in PubMed regarding IVF culture media including results from 1929 until March 2014. Information was gathered from the websites of companies who market culture media, advertising material, instructions for use and certificates of analysis. The regulation regarding IVF media mainly in the European Union (EU) but also in non-European countries was explored. RESULTS The keyword 'IVF culture media' gave 923 results in PubMed and 'embryo culture media' 12 068 results dating from 1912 until March 2014, depicting the increased scientific activity in this field. The commercialization of IVF culture media has increased the standards bringing a great variety of options into clinical practice. However, it has led to reduced transparency and comparisons of brand names that do not facilitate the scientific dialogue. Furthermore, there is some evidence suggesting that suboptimal culture conditions could cause long-term reprogramming in the embryo as the periconception period is particularly susceptible to epigenetic alterations. IVF media are now classified as class III medical devices and only CE (Conformité Européene)-marked media should be used in the EU. CONCLUSION The CE marking of IVF culture media is a significant development in the field. However, the quality and efficiency of culture media should be monitored closely. Well-designed randomized controlled trials, large epidemiological studies and full transparency should be the next steps. Reliable, standardized models assessing multiple end-points and post-implantation development should replace the mouse embryo assay. Structured long-term follow-up of children conceived by assisted reproduction technologies and traceability are of paramount importance.
Collapse
Affiliation(s)
- Elpiniki Chronopoulou
- Institute for Women's Health, University College London, 86-96 Chenies Mews, London WC1E 6HX, UK
| | - Joyce C Harper
- UCL Centre for PG and D, Institute for Women's Health, University College London, London, UK The Centre for Reproductive and Genetic Health, UCLH, London, UK
| |
Collapse
|
10
|
Park SK, Roh S, Park JI. A simplified one-step nuclear transfer procedure alters the gene expression patterns and developmental potential of cloned porcine embryos. J Vet Sci 2013; 15:73-80. [PMID: 23820223 PMCID: PMC3973768 DOI: 10.4142/jvs.2014.15.1.73] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 06/28/2013] [Indexed: 12/25/2022] Open
Abstract
Various somatic cell nuclear transfer (SCNT) techniques for mammalian species have been developed to adjust species-specific procedures to oocyte-associated differences among species. Species-specific SCNT protocols may result in different expression levels of developmentally important genes that may affect embryonic development and pregnancy. In the present study, porcine oocytes were treated with demecolcine that facilitated enucleation with protruding genetic material. Enucleation and donor cell injection were performed either simultaneously with a single pipette (simplified one-step SCNT; SONT) or separately with different pipettes (conventional two-step SCNT; CTNT) as the control procedure. After blastocysts from both groups were cultured in vitro, the expression levels of developmentally important genes (OCT4, NANOG, EOMES, CDX2, GLUT-1, PolyA, and HSP70) were analyzed by real-time quantitative polymerase chain reaction. Both the developmental rate according to blastocyst stage as well as the expression levels CDX2, EOMES, and HSP70 were elevated with SONT compared to CTNT. The genes with elevated expression are known to influence trophectoderm formation and heat stress-induced arrest. These results showed that our SONT technique improved the development of SCNT porcine embryos, and increased the expression of genes that are important for placental formation and stress-induced arrest.
Collapse
Affiliation(s)
- Sang Kyu Park
- Cellular Reprogramming and Embryo Biotechnology Laboratory, Dental Research Institute, Seoul National University School of Dentistry, Seoul 110-749, Korea
| | | | | |
Collapse
|
11
|
Cebrian-Serrano A, Salvador I, Raga E, Dinnyes A, Silvestre MA. Beneficial Effect of Melatonin on BlastocystIn VitroProduction from Heat-Stressed Bovine Oocytes. Reprod Domest Anim 2013; 48:738-46. [DOI: 10.1111/rda.12154] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 01/10/2013] [Indexed: 11/28/2022]
Affiliation(s)
| | - I Salvador
- Centro de Tecnología Animal; Instituto Valenciano de Investigaciones Agrarias; Segorbe; Spain
| | - E Raga
- Centro de Tecnología Animal; Instituto Valenciano de Investigaciones Agrarias; Segorbe; Spain
| | | | | |
Collapse
|
12
|
Timing of first embryonic cleavage is a positive indicator of the in vitro developmental potential of porcine embryos derived from in vitro fertilization, somatic cell nuclear transfer and parthenogenesis. Mol Reprod Dev 2011; 79:197-207. [DOI: 10.1002/mrd.22013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 11/29/2011] [Indexed: 12/11/2022]
|
13
|
Pribenszky C, Vajta G, Molnar M, Du Y, Lin L, Bolund L, Yovich J. Stress for Stress Tolerance? A Fundamentally New Approach in Mammalian Embryology1. Biol Reprod 2010; 83:690-7. [DOI: 10.1095/biolreprod.110.083386] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
14
|
Callesen H. Challenge testing of gametes to enhance their viability. Reprod Fertil Dev 2010; 22:40-6. [DOI: 10.1071/rd09213] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Embryos, oocytes and spermatozoa undergo several manipulations during the in vitro procedures that are an integral part of assisted reproductive technologies (ART) in mammals. Consequently, some of the gametes are damaged irreparably, whereas others react to these challenges with some sort of survival mechanism that enables them to come through the process. The details of the mechanism remain unknown but, if identified, it could have immense potential as a new way to improve the viability of embryos produced by ART. However, few publications describe systematic ways to challenge test gametes and then to use the results as a basis for improving gamete viability. Furthermore, new methods to monitor the reactions of gametes to such challenge tests are needed. In the present review, these two issues are discussed, as are some of the conditions necessary before a challenge test protocol can be part of future work with ART.
Collapse
|
15
|
Vajta G, Rienzi L, Cobo A, Yovich J. Embryo culture: can we perform better than nature? Reprod Biomed Online 2009; 20:453-69. [PMID: 20202911 DOI: 10.1016/j.rbmo.2009.12.018] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 07/20/2009] [Accepted: 12/09/2009] [Indexed: 11/27/2022]
Abstract
Culture of preimplantation-stage embryos has always been a key element of laboratory embryology and has contributed substantially to the success of many assisted reproduction procedures. During the past decade, its importance has increased as extended in-vitro embryo culture and single blastocyst transfer have become indispensable parts of the approach to decreasing the chance of multiple pregnancy while preserving the overall efficiency of the treatment. However, in spite of the scientific and commercial challenge stimulating research worldwide to optimize embryo culture conditions, a consensus is missing even in the basic principles, including composition and exchange of media, the required physical and biological environment and even the temperature of incubation. This review attempts to summarize the controversies, demonstrate the fragility of some widely accepted dogmas and generate an open-minded debate towards rapid and efficient optimization. New approaches expanding the traditional frames of mammalian embryo culture are also discussed. Although some researchers suppose that the efficiency of the presently applied in-vitro culture systems have already approached the biological limits, authors are confident that substantial improvement may be achieved that may expand considerably the possibilities of future assisted reproduction in humans.
Collapse
Affiliation(s)
- Gábor Vajta
- Cairns Fertility Centre, Cairns, QLD 4870, Australia.
| | | | | | | |
Collapse
|
16
|
Isom SC, Prather RS, Rucker Iii EB. Enhanced developmental potential of heat-shocked porcine parthenogenetic embryos is related to accelerated mitogen-activated protein kinase dephosphorylation. Reprod Fertil Dev 2009; 21:892-900. [PMID: 19698293 DOI: 10.1071/rd08268] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2008] [Accepted: 06/07/2009] [Indexed: 11/23/2022] Open
Abstract
Recently, we demonstrated that a 9-h heat shock of 42°C can have marked stimulatory effects on porcine parthenogenetic embryo development if applied immediately after oocyte activation. Developmental discrepancies between heat-shocked (HS) and non-HS embryos were manifest as early as 3 h after activation, suggesting involvement of maturation promoting factor (MPF) and/or mitogen-activated protein kinase (MAPK). Analysis of cdc2 kinase activity showed that MPF inactivation occurred at similar rates in HS and control embryos upon oocyte activation. However, MAPK dephosphorylation was accelerated in HS embryos compared with controls. Okadaic acid, a protein phosphatase inhibitor, maintained MAPK activity at high levels in both non-HS and HS embryos and sensitised HS embryos to the effects of elevated temperatures. No increase in heat shock proteins was observed in pronuclear-stage HS embryos. These data suggest that the acceleration of development observed in HS porcine parthenogenetic embryos is associated with a precocious inactivation of the MAPK signalling cascade. The faster cleavage divisions observed in HS embryos may be linked physiologically to their enhanced developmental potential in vitro.
Collapse
Affiliation(s)
- S Clay Isom
- Division of Animal Sciences, University of Missouri-Columbia, Columbia, MO, USA.
| | | | | |
Collapse
|