Low oxygen tension during in vitro maturation of porcine follicular oocytes improves parthenogenetic activation and subsequent development to the blastocyst stage

2005 ◽  
Vol 63 (5) ◽  
pp. 1277-1289 ◽  
Author(s):  
Masaki Iwamoto ◽  
Akira Onishi ◽  
Dai-ichiro Fuchimoto ◽  
Tamas Somfai ◽  
Kumiko Takeda ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
In Vitro Maturation ◽  
Subsequent Development ◽  
Blastocyst Stage ◽  
Low Oxygen ◽  
Parthenogenetic Activation ◽  
Low Oxygen Tension

247 EFFECTS OF CYSTEINE IN IVM MEDIA ON IN VITRO MATURATION UNDER LOW OXYGEN TENSION, IN VITRO FERTILIZATION, AND IN VITRO CULTURE OF PORCINE OOCYTES

2008 ◽  
Vol 20 (1) ◽  
pp. 203
Author(s):  
N. V. Linh ◽  
D. N. Q. Thanh ◽  
M. Ozawa ◽  
B. X. Nguyen ◽  
K. Kikuchi ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Blastocyst Stage ◽  
Low Oxygen ◽  
In Vitro Production ◽  
Vitro Fertilization ◽  
Nuclear Maturation ◽  
Low Oxygen Tension ◽  
High O2 ◽  
Group 1

Cysteine is considered to promote male pronuclear (MPN) formation in porcine through oocyte glutathione (GSH) synthesis (Yoshida et al. 1993 Biol. Reprod. 49, 89–94). The GSH has an important role in providing cells with a redox state and in acting to protect cells from toxic effects of oxidative damage (Meister et al. 1976 AM Rev. Biochem. 45, 559–604). However, such previous investigations were carried out under high O2 tension (20% O2) incubation conditions. Here we simply study IVM-IVF-IVC competence of porcine oocytes matured in IVM media supplemented with cysteine of different concentrations under low oxygen tension (5% O2). Cumulus–oocyte complexes (COCs) from prepubertal gilts were collected, matured, and fertilized in vitro according to Kikuchi et al. (2000 Biol. Reprod. 66, 1033–1041). COCs were cultured in IVM medium supplemented with 0 (Group 1; control), 0.05 (Group 2), 0.1 (Group 3), 0.2 (Group 4), and 0.6 mm (Group 5) cysteine under low oxygen tension. Nuclear maturation of oocytes, fertilization status, and number of cells in resultant embryos were assessed with orcein staining; also, the GSH content of IVM oocytes was measured by the method described by Ozawa et al. (2002 Reproduction 124, 683–689). Maturation rates of Groups 1–5 were 68.2 � 3.2, 70.6 � 7.7, 69.7 � 15.9, 75.9 � 7.7, and 68.8 � 8.0%, respectively, indicating no difference in maturation competence among the groups (P > 0.05 by ANOVA). The rates of sperm penetration, MPN formation (95.9 � 2.4, 100 � 0, 92.8 � 4.7, 94.0 � 4.1, and 92.4 � 2.7%, respectively), monospermy, and even blastocyst rates after 6 days of IVC were not different among the groups (P > 0.05 by ANOVA). Moreover, the cell numbers of blastomeres in blastocysts (38.68 � 3.5, 40.1 � 3.1, 37.5 � 3.0, 36.2 � 3.3, and 43.8 � 4.0, respectively) were uniformly the same among the groups (P > 0.05 by ANOVA). However, GSH content of IVM oocytes increased significantly (P < 0.05 by ANOVA) as the concentration of cysteine increased (12.2 � 0.6, 14 � 0.8, 15.1 � 0.5, 16.4 � 0.4, and 16.4 � 0.5 pmol/oocyte, respectively). The GSH level of oocytes in Group 1 (control) seems to be higher than that reported by Aberydeera et al. (1998 Biol. Reprod. 58, 213–218), who matured porcine oocytes under high O2 tension. This may reflect the effect of low O2 tension and explain the same developmental rate to the blastocyst stage as that of oocytes matured in the media supplemented with cysteine in this study. In conclusion, an addition of 0.05–0.6 mm cysteine during IVM, under 5% O2 tension, of porcine oocytes significantly increased intracellular GSH synthesis according to its concentration. However, it had no promoting effects on nuclear maturation, fertilization, male pronucleus formation, and subsequent embryonic development to the blastocyst stage. Thus, O2 tension during IVM of oocytes is suggested to be important for the in vitro production of porcine blastocysts.

1 EFFECT OF OXYGEN TENSION DURING IN VITRO MATURATION AND FERTILIZATION ON BOVINE EMBRYO PRODUCTION AND CUMULUS-OOCYTE-COMPLEX mRNA ABUNDANCE

2009 ◽  
Vol 21 (1) ◽  
pp. 101
Author(s):  
P. Bermejo-Alvarez ◽  
D. Rizos ◽  
P. Lonergan ◽  
A. Gutierrez-Adan
Keyword(s):  
Gene Expression ◽  
Oxygen Tension ◽  
In Vitro Maturation ◽  
Cyclin B1 ◽  
Bovine Embryo ◽  
Low Oxygen ◽  
Embryo Production ◽  
Low Oxygen Tension ◽  
Developmental Rates

Despite physiological oxygen tension being lower than in atmospheric gas, both in vitro maturation and fertilization are generally conducted under atmospheric oxygen tension (20%). The objective of this study was to evaluate the effect of two different oxygen concentrations (20 and 5%) during in vitro maturation (M) and fertilization (F) on bovine embryo production and to analyze differences in gene expression between cumulus–oocyte-complexes (COC) matured at 5% (M5) or 20% (M20) oxygen tension. A total of 1179 COC were matured, fertilized and cultured in vitro in 5 replicates divided in 4 groups according to the oxygen tension used (M5F5, M5F20, M20F5 and M20F20). Cleavage was assessed every 4 h from 24 to 48 h post-insemination (pi) and blastocyst yield was recorded from Day 6 to Day 8. For gene expression analysis, 5 pools of 10 COC (not denuded) of each group were snap frozen after maturation and stored at –80°C. After RNA extraction and RTPCR, qPCR was used to quantify relative abundance of 7 genes: the M-phase promoting factor subunit Cyclin B1, insulin-growth factor 2 (IGFR2), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase A (LDHA), glucose-6-phosphate dehydrogenase (G6PD), glutathione peroxidase (GPX1), and the apoptosis related gene BAX. Histone 2A was used as housekeeping gene. Statistical analysis was performed analyzing two factors (M5 v. M20 and F5 v. F20) by two-way ANOVA (P ≤ 0.05) for embryo production and by one-way ANOVA (P ≤ 0.05) for gene expression. At every time point analyzed, maturation under low oxygen tension significantly improved both cleavage rate and blastocyst yield. However, the use of low oxygen tension at fertilization has a significant negative effect on developmental rates (48 hpi: M5F5: 71.6 ± 5.5; M5F20: 76.2 ± 2.7; M20F5: 40.1 ± 5.8; M20F20: 69.9 ± 0.8). (Day 6: M5F5: 12.6 ± 3; M5F20: 17.2 ± 2.4; M20F5: 2.5 ± 1.2; M20F20: 13.3 ± 4.) (Day 7: M5F5: 32.6 ± 4.9; M5F20: 38.8 ± 3.2; M20F5: 12.2 ± 1.2; M20F20: 34.2 ± 3.9.) (Day 8: M5F5: 35.5 ± 5; M5F20: 43.1 ± 5.1; M20F5: 15.6 ± 1.4; M20F20: 37.1 ± 4.2.) (Group: %Mean ± SEM). Four genes (Cyclin B1, GAPDH, IGFR2 and LDHA) were significantly upregulated in M5 COC, and three genes (GPX1, G6PD and BAX) did not show significant differences. In conclusion, low oxygen tension during maturation exerts a beneficial effect upon embryo development, whereas the opposite situation is observed during fertilization. Furthermore, the expression of a growth factor, a meiotic promoting factor and two enzymes of anaerobic glycolysis were significantly upregulated in COCs matured under low oxygen tension, which may be linked to the improvement in developmental rates.

Embryo culture at a reduced oxygen concentration of 5%: a mini review

Zygote ◽  
2019 ◽  
Vol 27 (6) ◽  
pp. 355-361 ◽  
Author(s):  
R. Sciorio ◽  
G.D. Smith
Keyword(s):  
Oxygen Tension ◽  
Embryo Development ◽  
Atmospheric Oxygen ◽  
Embryo Implantation ◽  
Critical Role ◽  
Low Oxygen ◽  
Physiological Level ◽  
Low Oxygen Tension

SummaryThe optimum oxygen tension for culturing mammalian embryos has been widely debated by the scientific community. While several laboratories have moved to using 5% as the value for oxygen tension, the majority of modern in vitro fertilization (IVF) laboratory programmes still use 20%. Several in vivo studies have shown the oxygen tension measured in the oviduct of mammals fluctuates between 2% and 8% and in cows and primates this values drops to <2% in the uterine milieu. In human IVF, a non-physiological level of 20% oxygen has been used in the past. However, several studies have shown that atmospheric oxygen introduces adverse effects to embryo development, not limited to numerous molecular and cellular physiology events. In addition, low oxygen tension plays a critical role in reducing the high level of detrimental reactive oxygen species within cells, influences embryonic gene expression, helps with embryo metabolism of glucose, and enhances embryo development to the blastocyst stage. Collectively, this improves embryo implantation potential. However, clinical studies have yielded contradictory results. In almost all reports, some level of improvement has been identified in embryo development or implantation, without any observed drawbacks. This review article will examine the recent literature and discusses ongoing efforts to understand the benefits that low oxygen tension can bring to mammal embryo development in vitro.

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