| 1. |
- Hallberg, Ida, et al.
(författare)
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Perfluorononanoic acid (PFNA) alters lipid accumulation in bovine blastocysts after oocyte exposure during in vitro maturation
- 2019
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 84, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorononanoic acid (PFNA) is one of the perfluoroalkyl acids present in human tissues. In this study, effects on early embryo development after PFNA exposure were investigated using the bovine in vitro production system. Oocytes were exposed to PFNA during maturation in vitro (10 μg mL-1 and 0.1 μg mL-1), and then fertilized and cultured in parallel with control groups. Developmental parameters (cleavage, blastocyst formation) were followed and embryo quality evaluated (stage, grade). Embryos developed after exposure to 0.1 μg mL-1 were stained to distinguish nuclei, active mitochondria and neutral lipids. 10 μg mL-1 of PFNA had a severe negative effect on blastocyst formation (OR: 0.27 p < 0.05), an effect not observed at 0.1 μg mL-1. However, lipid droplet distribution was significantly altered in embryos exposed to 0.1 μg mL-1, suggesting a disturbance of lipid metabolism after exposure to sublethal levels of PFNA during oocyte maturation in vitro.
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| 4. |
- Laskowski, Denise, et al.
(författare)
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Insulin during in vitro oocyte maturation has an impact on development, mitochondria, and cytoskeleton in bovine day 8 blastocysts
- 2017
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Ingår i: Theriogenology. - : Elsevier BV. - 0093-691X .- 1879-3231. ; 101, s. 15-25
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Tidskriftsartikel (refereegranskat)abstract
- Insulin is a key metabolic hormone that controls energy homeostasis in the body, including playing a specific role in regulating reproductive functions. Conditions associated with hyperinsulinemia can lower developmental rates in bovine in vitro embryo production and are linked to decreased fertility in humans, as in cases of obesity or type 2 diabetes. Embryo quality is important for fertility outcome and it can be assessed by choosing scoring standards for various characteristics, such as developmental stage, quality grade, cell number, mitochondrial pattern or actin cytoskeleton structure. Changes in the embryo's gene expression can reflect environmental impacts during maturation and may explain morphological differences. Together with morphological evaluation, this could enable better assessment and possibly prediction of the developmental potential of the embryo. The aim of this study was to use a bovine model to identify potential gene signatures of insulin-induced changes in the embryo by combining gene expression data and confocal microscopy evaluation. Bovine embryos were derived from oocytes matured in two different insulin concentrations (10 mu g mL(-1) and 0.1 mu g mL(-1)), then stained to distinguish f-Actin, DNA and active mitochondria. The total cell number of the embryo, quality of the actin cytoskeleton and mitochondrial distribution were assessed and compared to an insulin-free control group. A microarray-based transcriptome analysis was used to investigate key genes involved in cell structure, mitochondrial function and cell division. Our results indicate that insulin supplementation during oocyte maturation leads to lower blastocyst rates and a different phenotype, characterised by an increased cell number and different actin and mitochondrial distribution patterns. These changes were reflected by an up-regulation of genes involved in cell division (MAP2K2; DHCR7), cell structure (LMNA; VIM; TUBB2B; TUBB3; TUBB4B) and mitochondrial activation (ATP5D; CYP11A1; NDUFB7; NDUFB10; NDUFS8). Taken together, we hypothesise that the increased proliferation in the insulin-treated groups might impair the developmental potential of the embryos by inducing metabolic stress on the molecular level, which could be detrimental for the survival of the embryo. (C) 2017 Elsevier Inc. All rights reserved.
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| 5. |
- Laskowski, Denise, et al.
(författare)
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Insulin exposure during in vitro bovine oocyte maturation changes blastocyst gene expression and developmental potential
- 2017
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Ingår i: Reproduction, Fertility and Development. - 1031-3613 .- 1448-5990. ; 29, s. 876-889
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Tidskriftsartikel (refereegranskat)abstract
- Metabolic imbalance impairs fertility, because changes in concentrations of metabolites and hormones in the blood and follicular fluid create an unfavourable environment for early embryonic development. Insulin is a key metabolic hormone known for its effects on fertility: insulin concentrations are increased during energy balance disturbances in diabetes or metabolic syndrome. Still, insulin is frequently used at supraphysiological concentrations for embryo in vitro culture with unknown consequences for the developmental potential of the offspring. In the present study we investigated the effects of insulin exposure during in vitro bovine oocyte maturation on developmental rates, embryo quality and gene expression. Supplementation of the maturation media with insulin at 10 or 0.1 mu gmL(-1) decreased blastocyst rates compared with an insulin-free control (19.8 +/- 1.3% and 20.4 +/- 1.3% vs 23.8 +/- 1.3%, respectively; P<0.05) and led to increased cell numbers (nearly 10% more cells on Day 8 compared with control; P<0.05). Transcriptome analysis revealed significant upregulation of genes involved in lipid metabolism, nuclear factor (erythroid-derived 2)-like 2 (NRF2) stress response and cell differentiation, validated by quantitative polymerase chain reaction. To conclude, the results of the present study demonstrate that insulin exposure during in vitro oocyte maturation has a lasting effect on the embryo until the blastocyst stage, with a potential negative effect in the form of specific gene expression perturbations.
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| 6. |
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| 7. |
- Laskowski, Denise, et al.
(författare)
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DNA methylation pattern of bovine blastocysts associated with hyperinsulinemia in vitro
- 2018
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Ingår i: Molecular Reproduction and Development. - : Wiley. - 1040-452X .- 1098-2795. ; 85, s. 599-611
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Tidskriftsartikel (refereegranskat)abstract
- Insulin functions as a regulator of metabolism and plays an important role in reproduction. Hyperinsulinemia is often observed in patients with obesity and diabetes type 2 and is known to impair fertility, but the underlying molecular mechanisms are only partly understood. Metabolic programming through epigenetic mechanisms such as DNA methylation during embryonic development can lead to health implications for the offspring later in life. Our aim was to study the potential effect of hyperinsulinemia on gene expression and DNA methylation of embryos by adding insulin (0.1 mu g/ml=INS0.1 or 10 mu g/ml=INS10) during in vitro oocyte maturation by using the EmbryoGENE DNA methylation array for a study of the bovine epigenome. Our results showed significant differences between blastocysts originating from insulin-treated oocytes compared with untreated control blastocysts. In total, 13,658 and 12,418 probes were differentially methylated (DM) in INS0.1 and INS10, respectively, with an overlap of 3,233 probes in the DM regions (DMR) for both insulin groups. Genes related to pathways such as lipid metabolism, growth and proliferation, mitochondrial function, and oxidative stress responses were influenced at both the epigenetic and transcriptomic levels. In addition, imprinted genes and genes with functions in the epigenetic machinery were among the DMRs. This study identified DMRs correlated to differential expression of genes involved in metabolic regulation and should help to improve our knowledge of the underlying molecular mechanisms of metabolic imbalance.
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| 8. |
- Laskowski, Denise, et al.
(författare)
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Lipid profile of bovine blastocysts exposed to insulin during in vitro oocyte maturation
- 2018
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Ingår i: Reproduction, Fertility and Development. - 1031-3613 .- 1448-5990. ; 30, s. 1253-1266
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Tidskriftsartikel (refereegranskat)abstract
- Insulin is a key hormone with important functions in energy metabolism and is involved in the regulation of reproduction. Hyperinsulinaemia is known to impair fertility (for example, in obese mothers); therefore, we aimed to investigate the impact of elevated insulin concentrations during the sensitive period of oocyte maturation on gene expression and lipid profiles of the bovine Day-8 embryo. Two different insulin concentrations were used during in vitro oocyte maturation (INS10 = 10 mu g mL(-1) and INS0.1 = 0.1 mu g mL(-1)) in order to observe possible dose-dependent effects or thresholds for hyperinsulinaemia in vitro. By investigating gene expression patterns by an mRNA microarray in combination with lipid profile analysis by desorption electrospray ionisation-mass spectrometry (DESI-MS) of embryos derived from insulin-treated oocytes, we gained further insights regarding molecular responses of embryos to insulin provocation during the first days of development. Lipid metabolism appeared to be influenced on multiple levels according to gene expression results but the profiles collected in positive-ion mode by DESI-MS (showing mostly ubiquinone, cholesteryl esters and triacylglycerols) did not differ significantly from controls. There are parallels in follicular development of ruminants and humans that make this bovine model relevant for comparative research on early human embryonic development during hyperinsulinaemia.
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| 9. |
- Leclercq, Anna, et al.
(författare)
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Occurrence of late-apoptotic symptoms in porcine preimplantation embryos upon exposure of oocytes to perfluoroalkyl substances (PFASs) under in vitro meiotic maturation
- 2022
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- The objectives of this study were to evaluate the effect of perfluoroalkyl substances on early embryonic development and apoptosis in blastocysts using a porcine in vitro model. Porcine oocytes (N = 855) collected from abattoir ovaries were subjected to perfluorooctane sulfonic acid (PFOS) (0.1 μg/ml) and perfluorohexane sulfonic acid (PFHxS) (40 μg/ml) during in vitro maturation (IVM) for 45 h. The gametes were then fertilized and cultured in vitro, and developmental parameters were recorded. After 6 days of culture, resulting blastocysts (N = 146) were stained using a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and imaged as stacks using confocal laser scanning microscopy. Proportion of apoptotic cells as well as total numbers of nuclei in each blastocyst were analyzed using objective image analysis. The experiment was run in 9 replicates, always with a control present. Effects on developmental parameters were analyzed using logistic regression, and effects on apoptosis and total numbers of nuclei were analyzed using linear regression. Higher cell count was associated with lower proportion of apoptotic cells, i.e., larger blastocysts contained less apoptotic cells. Upon PFAS exposure during IVM, PFHxS tended to result in higher blastocyst rates on day 5 post fertilization (p = 0.07) and on day 6 post fertilization (p = 0.05) as well as in higher apoptosis rates in blastocysts (p = 0.06). PFHxS resulted in higher total cell counts in blastocysts (p = 0.002). No effects attributable to the concentration of PFOS used here was seen. These findings add to the evidence that some perfluoroalkyl substances may affect female reproduction. More studies are needed to better understand potential implications for continued development as well as for human health.
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| 10. |
- Al-Essawe, Essraa M, et al.
(författare)
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Seminal plasma influences the fertilizing potential of cryopreserved stallion sperm
- 2018
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Ingår i: Theriogenology. - : Elsevier BV. - 0093-691X .- 1879-3231. ; 115, s. 99-107
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Tidskriftsartikel (refereegranskat)abstract
- Seminal plasma (SP) contains proteins that may influence cryosurvival and prevent capacitation-like changes due to freezing and thawing. The objective of this study was to investigate the effect of adding pooled SP from "good" (GF) or "bad" (BF) freezer stallions on sperm cells' fertilizing ability. "Good freezers" refers to stallions that usually produce ejaculates which can withstand cryopreservation, whilst "bad freezer" stallions produce ejaculates which cannot tolerate the freezing process. A heterologous zona binding assay with in vitro matured bovine oocytes was used to assess the binding ability of equine sperm cells as a possible alternative to artificial insemination trials. The effect of adding SP i) prior to cryopreservation; ii) after thawing of sperm cells selected by single layer centrifugation (SLC); iii) to capacitation medium, was evaluated. Adding SP from GE stallions prior to cryopreservation reduced the mean number of sperm cells bound to the zona pellucida (ZP) compared to control (P = 0.0003), SP-free sperm cells and group received SP from BF stallions (P < 0.0001 for both). After thawing SLC-selected sperm cells treated with 5% SP showed a decrease in binding ability compared with SP-free sperm cells (P < 0.0001). The binding affinity of sperm cells was higher in the group treated with SP from GF than with SP from BF stallions (P < 0.05). Prolonged exposure to SP impaired the ability of stallion sperm cells to undergo capacitation and bind to ZP, regardless of the source of SP (P < 0.0001). The response of equine sperm cells to SP is influenced by the ability of the sperm cells to withstand cryopreservation and is affected by the timing of exposure and the origin of SP. Customization of the protocol for individual stallions is recommended to optimize the effect. (C) 2018 Elsevier Inc. All rights reserved.
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