Low oxygen tension increases mitochondrial membrane potential and enhances expression of antioxidant genes and implantation protein of mouse blastocyst cultured in vitro

Yun Yi Ma, Huei Wen Chen, Chii Ruey Tzeng

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9 Citations (Scopus)

Abstract

Background: In human IVF, embryos cultured with a lower O2 tension (5%) can give rise to higher success rates when compared with normoxic conditions (20%). However, the mechanisms behind the beneficial effects of reduced oxygen tension in embryogenesis remain unclear. The aim of this study was to evaluate the expression of oxygen related and antioxidant genes and mitochondrial function in mouse embryo cultured under hypoxic and normoxic conditions, to investigate the beneficial effect of low oxygen tension in preimplantation embryogenesis. Methods: Two-cell ICR mouse embryos were cultured to blastocysts under different oxygen tension (3% and 20%). The gene expression of oxygen-related proteins (hypoxia-inducible factor, HIF), HIF targets (vascular endothelial growth factor, VEGF; glucose transporter 3, GLUT-3) and antioxidants (manganese superoxide dismutase, MnSOD; peroxiredoxin 5, PRDX5) were assessed using quantitative RT-PCR and implantation-related protein (Leukemia Inhibitory Factor Receptor, LIFR) was validated by immunofluorescence. Apoptosis, mitochondrial membrane potential (MtMP) and ROS levels were measured by TUNEL, JC-1 and DCFDA assays, respectively. Results: Blastocyst development rate (92.3% vs. 79.4%) and hatch rate (80% vs. 70.4%) were both higher in embryos cultured in 3% O2 than in 20% O2. The transcription levels of MnSOD, PRDX5, VEGF and GLUT-3 also significantly increased in 3% O2 compared with 20% O2 (P < 0.05). Immunofluorescence showed that the intensity of staining for HIF-2α, MnSOD and LIFR were higher in 3% O2. Blastocysts cultured under 3% O2 exhibited significantly higher MtMP compared with 20% O2. ROS and Apoptosis levels were significantly higher in the 20% O2 group than in the 3% O2 group (P < 0.05). Conclusions: Low O2 tension may improve embryo viability by increasing expression of antioxidant enzymes and glucose transporter activities. It provides an environment conducive to viability by upregulation of LIFR/VEGF and increased MtMP which could enhance implantation potential and reduce apoptosis in mouse blastocyst. These effects may be initiated and regulated by HIF-2α, a key mediator in a hypoxic environment.

Original languageEnglish
Article number47
JournalJournal of Ovarian Research
Volume10
Issue number1
DOIs
Publication statusPublished - Jul 20 2017

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Mitochondrial Membrane Potential
Blastocyst
OSM-LIF Receptors
Embryonic Structures
Antioxidants
Vascular Endothelial Growth Factor A
Oxygen
Facilitative Glucose Transport Proteins
Apoptosis
Proteins
Embryonic Development
Fluorescent Antibody Technique
Peroxiredoxins
Inbred ICR Mouse
Mitochondrial Genes
In Situ Nick-End Labeling
Superoxide Dismutase
Up-Regulation
In Vitro Techniques
Staining and Labeling

Keywords

  • Antioxidant
  • Hypoxia
  • Implantation
  • Mitochondria
  • Mouse embryo

ASJC Scopus subject areas

  • Oncology
  • Obstetrics and Gynaecology

Cite this

@article{c15c4471c238479ab7dc74054c4c1de2,
title = "Low oxygen tension increases mitochondrial membrane potential and enhances expression of antioxidant genes and implantation protein of mouse blastocyst cultured in vitro",
abstract = "Background: In human IVF, embryos cultured with a lower O2 tension (5{\%}) can give rise to higher success rates when compared with normoxic conditions (20{\%}). However, the mechanisms behind the beneficial effects of reduced oxygen tension in embryogenesis remain unclear. The aim of this study was to evaluate the expression of oxygen related and antioxidant genes and mitochondrial function in mouse embryo cultured under hypoxic and normoxic conditions, to investigate the beneficial effect of low oxygen tension in preimplantation embryogenesis. Methods: Two-cell ICR mouse embryos were cultured to blastocysts under different oxygen tension (3{\%} and 20{\%}). The gene expression of oxygen-related proteins (hypoxia-inducible factor, HIF), HIF targets (vascular endothelial growth factor, VEGF; glucose transporter 3, GLUT-3) and antioxidants (manganese superoxide dismutase, MnSOD; peroxiredoxin 5, PRDX5) were assessed using quantitative RT-PCR and implantation-related protein (Leukemia Inhibitory Factor Receptor, LIFR) was validated by immunofluorescence. Apoptosis, mitochondrial membrane potential (MtMP) and ROS levels were measured by TUNEL, JC-1 and DCFDA assays, respectively. Results: Blastocyst development rate (92.3{\%} vs. 79.4{\%}) and hatch rate (80{\%} vs. 70.4{\%}) were both higher in embryos cultured in 3{\%} O2 than in 20{\%} O2. The transcription levels of MnSOD, PRDX5, VEGF and GLUT-3 also significantly increased in 3{\%} O2 compared with 20{\%} O2 (P < 0.05). Immunofluorescence showed that the intensity of staining for HIF-2α, MnSOD and LIFR were higher in 3{\%} O2. Blastocysts cultured under 3{\%} O2 exhibited significantly higher MtMP compared with 20{\%} O2. ROS and Apoptosis levels were significantly higher in the 20{\%} O2 group than in the 3{\%} O2 group (P < 0.05). Conclusions: Low O2 tension may improve embryo viability by increasing expression of antioxidant enzymes and glucose transporter activities. It provides an environment conducive to viability by upregulation of LIFR/VEGF and increased MtMP which could enhance implantation potential and reduce apoptosis in mouse blastocyst. These effects may be initiated and regulated by HIF-2α, a key mediator in a hypoxic environment.",
keywords = "Antioxidant, Hypoxia, Implantation, Mitochondria, Mouse embryo",
author = "Ma, {Yun Yi} and Chen, {Huei Wen} and Tzeng, {Chii Ruey}",
year = "2017",
month = "7",
day = "20",
doi = "10.1186/s13048-017-0344-1",
language = "English",
volume = "10",
journal = "Journal of Ovarian Research",
issn = "1757-2215",
publisher = "BioMed Central",
number = "1",

}

TY - JOUR

T1 - Low oxygen tension increases mitochondrial membrane potential and enhances expression of antioxidant genes and implantation protein of mouse blastocyst cultured in vitro

AU - Ma, Yun Yi

AU - Chen, Huei Wen

AU - Tzeng, Chii Ruey

PY - 2017/7/20

Y1 - 2017/7/20

N2 - Background: In human IVF, embryos cultured with a lower O2 tension (5%) can give rise to higher success rates when compared with normoxic conditions (20%). However, the mechanisms behind the beneficial effects of reduced oxygen tension in embryogenesis remain unclear. The aim of this study was to evaluate the expression of oxygen related and antioxidant genes and mitochondrial function in mouse embryo cultured under hypoxic and normoxic conditions, to investigate the beneficial effect of low oxygen tension in preimplantation embryogenesis. Methods: Two-cell ICR mouse embryos were cultured to blastocysts under different oxygen tension (3% and 20%). The gene expression of oxygen-related proteins (hypoxia-inducible factor, HIF), HIF targets (vascular endothelial growth factor, VEGF; glucose transporter 3, GLUT-3) and antioxidants (manganese superoxide dismutase, MnSOD; peroxiredoxin 5, PRDX5) were assessed using quantitative RT-PCR and implantation-related protein (Leukemia Inhibitory Factor Receptor, LIFR) was validated by immunofluorescence. Apoptosis, mitochondrial membrane potential (MtMP) and ROS levels were measured by TUNEL, JC-1 and DCFDA assays, respectively. Results: Blastocyst development rate (92.3% vs. 79.4%) and hatch rate (80% vs. 70.4%) were both higher in embryos cultured in 3% O2 than in 20% O2. The transcription levels of MnSOD, PRDX5, VEGF and GLUT-3 also significantly increased in 3% O2 compared with 20% O2 (P < 0.05). Immunofluorescence showed that the intensity of staining for HIF-2α, MnSOD and LIFR were higher in 3% O2. Blastocysts cultured under 3% O2 exhibited significantly higher MtMP compared with 20% O2. ROS and Apoptosis levels were significantly higher in the 20% O2 group than in the 3% O2 group (P < 0.05). Conclusions: Low O2 tension may improve embryo viability by increasing expression of antioxidant enzymes and glucose transporter activities. It provides an environment conducive to viability by upregulation of LIFR/VEGF and increased MtMP which could enhance implantation potential and reduce apoptosis in mouse blastocyst. These effects may be initiated and regulated by HIF-2α, a key mediator in a hypoxic environment.

AB - Background: In human IVF, embryos cultured with a lower O2 tension (5%) can give rise to higher success rates when compared with normoxic conditions (20%). However, the mechanisms behind the beneficial effects of reduced oxygen tension in embryogenesis remain unclear. The aim of this study was to evaluate the expression of oxygen related and antioxidant genes and mitochondrial function in mouse embryo cultured under hypoxic and normoxic conditions, to investigate the beneficial effect of low oxygen tension in preimplantation embryogenesis. Methods: Two-cell ICR mouse embryos were cultured to blastocysts under different oxygen tension (3% and 20%). The gene expression of oxygen-related proteins (hypoxia-inducible factor, HIF), HIF targets (vascular endothelial growth factor, VEGF; glucose transporter 3, GLUT-3) and antioxidants (manganese superoxide dismutase, MnSOD; peroxiredoxin 5, PRDX5) were assessed using quantitative RT-PCR and implantation-related protein (Leukemia Inhibitory Factor Receptor, LIFR) was validated by immunofluorescence. Apoptosis, mitochondrial membrane potential (MtMP) and ROS levels were measured by TUNEL, JC-1 and DCFDA assays, respectively. Results: Blastocyst development rate (92.3% vs. 79.4%) and hatch rate (80% vs. 70.4%) were both higher in embryos cultured in 3% O2 than in 20% O2. The transcription levels of MnSOD, PRDX5, VEGF and GLUT-3 also significantly increased in 3% O2 compared with 20% O2 (P < 0.05). Immunofluorescence showed that the intensity of staining for HIF-2α, MnSOD and LIFR were higher in 3% O2. Blastocysts cultured under 3% O2 exhibited significantly higher MtMP compared with 20% O2. ROS and Apoptosis levels were significantly higher in the 20% O2 group than in the 3% O2 group (P < 0.05). Conclusions: Low O2 tension may improve embryo viability by increasing expression of antioxidant enzymes and glucose transporter activities. It provides an environment conducive to viability by upregulation of LIFR/VEGF and increased MtMP which could enhance implantation potential and reduce apoptosis in mouse blastocyst. These effects may be initiated and regulated by HIF-2α, a key mediator in a hypoxic environment.

KW - Antioxidant

KW - Hypoxia

KW - Implantation

KW - Mitochondria

KW - Mouse embryo

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U2 - 10.1186/s13048-017-0344-1

DO - 10.1186/s13048-017-0344-1

M3 - Article

C2 - 28728562

AN - SCOPUS:85025085949

VL - 10

JO - Journal of Ovarian Research

JF - Journal of Ovarian Research

SN - 1757-2215

IS - 1

M1 - 47

ER -