Protamine dissociation before decondensation of sperm nuclei during in vitro fertilization of pig oocytes

Reproduction ◽  
2000 ◽  
pp. 247-256 ◽  
Author(s):  
A Shimada ◽  
K Kikuchi ◽  
J Noguchi ◽  
K Akama ◽  
M Nakano ◽  
...  

The correlation between morphological changes and the dynamics of protamine in boar sperm chromatin during in vitro fertilization of pig oocytes matured in vitro was assessed. For this purpose, protamine was purified from boar sperm nuclei and an antiserum against protamine was developed. After affinity purification, the antiserum reacted exclusively with boar protamine during western blotting, showing no crossreactivity with core histones. Immunohistochemical evaluation revealed that only fully developed spermatid nuclei in boar testes stained strongly with the antiserum. When pig oocytes matured in vitro were fertilized in vitro, sperm penetration was observed in 37% of oocytes at 2 h after insemination and the penetration rate increased to 99% by 5 h after insemination, accompanied by an increase in polyspermic penetration. Paraffin wax sections of the inseminated oocytes were examined by immunohistochemical analysis with the antiserum. The proportion of condensed sperm nuclei that reacted with the antiserum was 87% of the sperm nuclei that penetrated by 2 h after insemination, and this decreased to 20 and 13% at 3 and 5 h after insemination, respectively. However, none of the decondensing sperm nuclei or male pronuclei reacted with the antiserum during the entire insemination period. These results indicate that a specific antiserum against boar protamine can be raised and, using this serum, it has been demonstrated that protamine is dissociated from boar sperm nuclei before decondensation during in vitro fertilization.

2004 ◽  
Vol 16 (2) ◽  
pp. 264
Author(s):  
Y.J. Yi ◽  
M.Y. Kim ◽  
Y.J. Chang ◽  
D.I. Jin ◽  
C.S. Park

The use of boar sperm stored at 4°C may be a useful tool for in vitro production of pig embryos. Therefore, this study was undertaken to investigate the effect of fertilization time of pig oocytes matured in-vitro by boar sperm. The sperm-rich fraction (30–60mL) was slowly cooled to room temperature (20–23°C) by 2h after collection. Semen was transferred into 15-mL tubes, centrifuged at room temperature for 10min at 800g, and the supernatant solution was poured off. The concentrated sperm was resuspended with 5mL of the LEN (11.0g lactose hydrate, 20mL egg yolk, 0.05g N-acetyl-D-glucosamine and 100mL distilled water) diluent to provide 1.0×109 spermmL−1 at room temperature. The resuspended semen was cooled in a refrigerator to 4°C. The medium used for oocyte maturation was TCM-199 supplemented with 26.19mM sodium bicarbonate, 0.9mM sodium pyruvate, 10μgmL−1 insulin, 2μgmL−1 vitamin B12, 25mM HEPES, 10μgmL−1 bovine apotransferrin, 150μM cysteamine, 10IUmL−1 PMSG, 10IUmL−1 hCG, 10ngmL−1 EGF, 0.4% BSA, 75μgmL−1 sodium penicillin G, 50μgmL−1 streptomycin sulfate and 10% pFF. After about 22h of maturation, oocytes were cultured without cysteamine and hormones for 22h at 38.5°C, 5% CO2 in air. Oocytes were inseminated with boar sperm stored at 4°C for 2 days after collection. Oocytes were coincubated for 1, 3, 6 and 9h in 500μL TBM fertilization media with 1×106mL−1 sperm concentration. Thereafter, oocytes were transferred into 500μL NCSU-23 culture medium containing 0.4% BSA for further culture of 6, 48 and 144h, fixed and stained for the evaluation of fertilization parameters and developmental ability. Data were analysed by ANOVA and Duncan’s multiple range test using the SAS program. The rates of sperm penetration and male pronuclear formation were higher in the fertilization times of 6 and 9h than in those of 1 and 3h. The percentage of polyspermic oocytes was highest in fertilization time of 9h compared with other incubation times. The rates of cleaved oocytes were higher in the fertilization times of 6 and 9h (85.0 and 84.6%) compared with those of 1 and 3h (61.1 and 76.8%). The percentage of blastocyst formation from the cleaved oocytes was highest in the fertilization time of 6h (33.6%) than in that of 1, 3 and 9h (11.4, 23.0 and 29.6%). Mean cell numbers per blastocyst were 32.9±3.3, 27.6±2.7, 26.3±2.2 and 24.4±1.8 in the fertilization times of 6, 9, 3 and 1h, respectively. In conclusion, we found out that boar sperm stored at 4°C could be used for in vitro fertilization of pig oocytes matured in vitro. Also, we recommend the coincubation time of 6h in 500μL TBM fertilization medium with 1×106mL−1 sperm concentration for in vitro fertilization of pig oocytes matured in vitro.


Reproduction ◽  
2002 ◽  
pp. 565-572 ◽  
Author(s):  
Y Nakazawa ◽  
A Shimada ◽  
J Noguchi ◽  
I Domeki ◽  
H Kaneko ◽  
...  

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.


2019 ◽  
Vol 210 ◽  
pp. 106178 ◽  
Author(s):  
Zhiqiang Ren ◽  
Weike Shaoyong ◽  
Qian Li ◽  
Lu Ma ◽  
Junying Xiao ◽  
...  

2018 ◽  
Vol 121 ◽  
pp. 21-26 ◽  
Author(s):  
Xiao-gang Weng ◽  
Ming-ming Cai ◽  
Yu-ting Zhang ◽  
Yan Liu ◽  
Zheng-ling Gao ◽  
...  

2012 ◽  
Vol 24 (1) ◽  
pp. 172 ◽  
Author(s):  
M. J. Sanchez-Calabuig ◽  
P. Beltran-Brena ◽  
E. Martinez-Nevado ◽  
D. Rizos ◽  
J. F. Perez-Gutierrez ◽  
...  

Assisted reproductive technologies are of great importance for increasing genetic diversity in captive animals without displacing them. The development and improvement of these techniques require accurate methods to assess sperm function. The ability of the sperm to bind the zona pellucida and the formation of a male pronucleus have been shown to have a high predictive value for fertilization outcome. The use of zona-intact bovine in vitro–matured oocytes in heterologous fertilization with dolphin spermatozoa could provide valuable information on its fertilizing ability. The aim of the present study was to evaluate male pronuclear formation in zona-intact bovine oocytes after coincubation with frozen-thawed bottlenose dolphin spermatozoa. A total of 1546 immature cumulus oocytes complexes (COC) were obtained from bovine ovaries collected at slaughter. The COC were matured for 24 h in TCM-199 supplemented with 10 ng mL–1 of epidermal growth factor and 10% FCS. Matured COC were inseminated with frozen-thawed Bovi-pure (Nidacon International, Mölndal, Sweden) separated bovine (control) or dolphin spermatozoa. At 18, 20, 22, 24, 26 and 28 h post-insemination (hpi), half of the presumptive zygotes from each group were fixed and stained with Hoechst 33342 to examine sperm penetration, polyspermy and pronuclear formation and the remainder were cultured in synthetic oviduct fluid supplemented with 5% FCS for evaluating fertilization rates by cleavage on Days 2 and 4 (Day 0 = day of IVF). As expected, in the control a higher percentage of 2 pronuclear formation was observed at 18 hpi (74.5%), with a decrease at 20 and 22 hpi (57.4 and 43.2%, respectively) and was significantly lower (P ≤ 0.001) at 24 hpi (13.3%), reaching the lowest values at 26 and 28 hpi. However, in the heterologous group significantly less oocytes with both pronuclear formed (P ≤ 0.001) were observed at 18, 20 and 22 hpi (1.2, 3.4 and 3.0%, respectively) compared with 24, 26 and 28 hpi (22.5, 11.4 and 8.9%, respectively). No polyspermy was detected in oocytes coincubated with dolphin spermatozoa. Moreover, the cleavage rate at Day 2 and 4 in heterologous fertilization was 13.0 and 34.8%, respectively, whereas for the control it was 90.0%. In conclusion, these results indicate that dolphin spermatozoa can penetrate bovine oocytes and induce the block to polyspermy and the differences found regarding pronuclear formation times between the 2 species could be due to distinct sperm chromatin organisation or condensation. In conclusion, our preliminary results show that heterologous fertilization using bovine oocytes is useful for characterising the viability of dolphin thawed spermatozoa, which also could be helpful in performing a more complete sperm evaluation. Further studies are necessary to provide more consistent evidence of the efficiency of this test. The authors thank the staff at Zoo Aquarium Madrid for their dedicated work toward dolphin semen collection.


1994 ◽  
Vol 41 (1) ◽  
pp. 249
Author(s):  
C. Matás ◽  
E. Martínez ◽  
J.M. Vázquez ◽  
J. Roca ◽  
J. Gadea ◽  
...  

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