scholarly journals Excess polyspermy reduces the ability of porcine oocytes to promote male pronuclear formation after in vitro fertilization

2021 ◽  
Vol 92 (1) ◽  
Author(s):  
Hiep Thi Nguyen ◽  
Thanh Quang Dang‐Nguyen ◽  
Tamas Somfai ◽  
Nguyen Thi Men ◽  
Barbara Beck‐Woerner ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Vitro Fertilization ◽  
Pronuclear Formation

In vitro maturation and in vitro fertilization of bovine oocytes cultured in a chemically defined, protein-free medium: effects of carbohydrates and amino acids

1999 ◽  
Vol 11 (2) ◽  
pp. 127 ◽  
Author(s):  
J. M. Lim ◽  
B. C. Lee ◽  
E. S. Lee ◽  
H. M. Chung ◽  
J. J. Ko ◽  
...  
Keyword(s):  
Amino Acids ◽  
In Vitro Fertilization ◽  
In Vitro Maturation ◽  
Essential Amino Acids ◽  
Defined Medium ◽  
Blastocyst Stage ◽  
Vitro Fertilization ◽  
Pronuclear Formation ◽  
Bovine Oocytes

This study was conducted to examine the effects of carbohydrates and amino acids on the maturation and fertilization of bovine oocytes. To evaluate the effect of each treatment without any unpredictable interference, oocytes were cultured in a simply defined medium (modified Tyrode’s medium; mT) without the addition of hormones and proteins. In Experiment 1, oocyte maturation to the metaphase-II stage was significantly (P<0.0001) enhanced after the addition of glucose (5.6 mМ), lactate (10 mМ) and/or pyruvate (0.5 mМ) to mT (37–74%) than after no addition (0%). In mT supplemented with glucose, the addition of 19 essential and non-essential amino acids (aa; 0, 0.01, 0.1, 1, 5 or 10%) did not further improve in vitro maturation (Experiment 2) or in vitro fertilization (Experiment 3) of oocytes. However, more (P<0.05) pronuclear formation after in vitro-insemination was found in oocytes matured in mT with 1% aa and glucose than in oocytes matured in mT with glucose alone (56% vs. 35%). Penetration of spermatozoa into the ooplasm was initiated at 3 h after insemination and pronuclear formation from 8 h (Experiment 4). When cultured inseminated oocytes were examined up to 192 h post insemination, a significant (P<0.05) increase in the number of 2-cell (18 v. 38%) and 8-cell embryos, (7 v. 20%) and morulae (0 v. 8%) was found after the addition of 1% aa to mT with glucose than after no addition (Experiment 5). A limited number of oocytes matured in mT with aa and glucose developed to the blastocyst stage (6%). These results indicate that exogenous carbohydrates and amino acids are prerequisites for the maturation and fertilization of bovine oocytes in vitro. Glucose alone promotes the nuclear maturation of oocytes, whereas amino acids aid the pronuclear formation of fertilized oocytes.

Nuclear-to-cytoplasmic ratios of 1PN and 2PN zygotes after in vitro fertilization of mouse oocytes

Zygote ◽  
2021 ◽  
pp. 1-5
Author(s):  
Natsumi Okajima ◽  
Wei Xiao ◽  
Alex Lopata ◽  
Tadashi Sankai ◽  
Lubna Yasmin ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Average Volume ◽  
Vitro Fertilization ◽  
Male Pronucleus ◽  
Mouse Oocytes ◽  
Female Pronucleus ◽  
Oocyte Cytoplasm ◽  
Pronuclear Formation

Summary Numerous studies have reported comparisons of the nuclear-to-cytoplasmic (NC) ratio during mitosis. However, little information is known about how the pronuclear size is regulated and determined at the end of meiosis II in mammalian zygotes. The present study aims to analyze the NC ratio of female and male pronuclei, and also to compare the size of single pronuclei using photographs that were obtained during experiments to create chimeric hermaphrodites from 2-cell oocytes. The volume of both the female and the male pronucleus was found to correlate with the volume of the oocyte cytoplasm. The NC ratio of the male pronucleus was greater than that of the female pronucleus. The NC ratio of the average volume of the female and male pronuclei was greater than the NC ratio of the mononucleate oocytes. The occurrence of 1PN oocytes was significantly higher when the volume of cytoplasm was lower than the cut-off value. These results indicated that the NC ratio is retained during pronuclear formation. A higher NC ratio in male compared with the female pronucleus indicated structural and/or molecular difference between the two pronuclei. 1PN formation may occur when sperm enters close to the MII spindle.

scholarly journals Replacement of nuclear protein by histone in pig sperm nuclei during in vitro fertilization

Reproduction ◽  
2002 ◽  
pp. 565-572 ◽  
Author(s):  
Y Nakazawa ◽  
A Shimada ◽  
J Noguchi ◽  
I Domeki ◽  
H Kaneko ◽  
...  
Keyword(s):  
In Vitro Fertilization ◽  
Nuclear Protein ◽  
Condensed State ◽  
Serial Sections ◽  
Vitro Fertilization ◽  
Sperm Penetration ◽  
Sperm Nuclei ◽  
Pronuclear Formation ◽  
Boar Spermatozoa

Sperm-specific nuclear protamines are dissociated before decondensation of sperm nuclei during fertilization in pigs. In the present study, replacement of nuclear protein by histone in boar spermatozoa during in vitro fertilization was evaluated by immunohistochemistry using anti-histone antibody. First, the specificity of the antibody used in this study was examined. Immunohistochemistry of the testes and epididymides indicated that somatic nuclei, but not elongated spermatids or maturing spermatozoa, were immunoreactive. Furthermore, immunoreaction was diminished after the antibody had been preincubated with unfractionated histone, indicating that the antibody was specific for the somatic nuclear histone. Immunohistochemistry of serial sections of oocytes, which were matured and co-cultured with boar spermatozoa for 2 to 6 h indicated that, at 2 to 3 h after insemination, penetrating sperm nuclei in the condensed state were not immunoreactive. At 4 to 5 h after insemination, some of the condensed sperm nuclei were immunoreactive in part or over the whole area of the nucleus, and all of the decondensing nuclei and male pronuclei were immunoreactive. At 6 h after insemination, the decondensing sperm nuclei and well-developed male pronuclei were immunoreactive. These results imply that, in pigs, remodelling of sperm nuclear protein from protamine to histone is initiated at the time of sperm penetration, before onset of decondensation and male pronuclear formation.

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