Register      Login
Reproduction, Fertility and Development Reproduction, Fertility and Development Society
Vertebrate reproductive science and technology
RESEARCH ARTICLE

Effect of tubal explants and their secretions on bovine spermatozoa: modulation of ROS production and DNA damage

Patricia Navarrete Gómez A , Juan G. Alvarez B , Jennie Risopatrón C D , Fernando Romero A E and Raúl Sánchez D E F
+ Author Affiliations
- Author Affiliations

A Center of Neurosciences and Peptides Biology (CEBIOR), Centre of Excellence in Biotechnology in Reproduction (BIOREN), University of La Frontera, Box 54-B, Temuco, Chile.

B Androgen, La Coruña, Spain.

C Department of Basic Sciences, Faculty of Medicine, BIOREN-CEBIOR, University of La Frontera, Temuco, Chile.

D Centre of Excellence in Biotechnology in Reproduction (CEBIOR), BIOREN, University of La Frontera, Temuco, Chile.

E Department of Preclinical Science, Faculty of Medicine, BIOREN-CEBIOR, University of La Frontera, Temuco, Chile.

F Corresponding author. Email: rsanchez@ufro.cl

Reproduction, Fertility and Development 24(6) 871-876 https://doi.org/10.1071/RD11180
Submitted: 16 July 2011  Accepted: 20 January 2012   Published: 22 February 2012

Abstract

Although low levels of reactive oxygen species (ROS) play a physiological role in maintaining sperm function, an increase in ROS generation above these levels may result in the induction of sperm membrane and DNA damage. The main objective of this study was to determine whether bovine oviducal explants (TU) and their conditioned media (CM) have a modulatory effect on the production of ROS, and consequently, on sperm DNA integrity. Thawed sperm were exposed to bovine TU and to CM obtained from the ampullar and isthmal regions after 4 and 12 h, and DNA damage and intracellular ROS production was assessed by TUNEL and DHE and SYTOX Green, respectively. Co-incubation of spermatozoa with oviducal explants from the ampullar region (TUa) for 4 h resulted in a statistically significant increase in the percentage of spermatozoa with DNA damage compared with controls (P = 0.0106), and this increase was positively correlated with ROS levels. Conversely, although the incubation of spermatozoa with explants and conditioned media from the isthmal region (TUi and CMi, respectively) for 12 h resulted in an increase of spermatozoa with DNA damage compared with controls (P < 0.0001), this increase was not correlated with ROS levels. In conclusion, significant oxidative stress may take place in the oviduct, particularly during short-term incubation, and this may be related to changes in the antioxidant factors present in the oviducal cells and secretions. A redox imbalance in pro-oxidants and antioxidants in the oviduct may lead to oxidative stress and sperm DNA damage.

Additional keywords: DNA fragmentation, oviducal explants, oviducal secretions.


References

Aitken, R. J., and Baker, M. A. (2004). Oxidative stress and male reproductive biology. Reprod. Fertil. Dev. 16, 581–588.
Oxidative stress and male reproductive biology.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXlvVensLo%3D&md5=b6a595e39ef841679cc9bf1892e76d95CAS | 15367373PubMed |

Aitken, R. J., Gordon, E., Harkiss, D., Twigg, J. P., Milne, P., and Jennings, Z. (1998). Relative impact of oxidative stress on functional competence and genomic integrity of human spermatozoa. Biol. Reprod. 59, 1037–1046.
Relative impact of oxidative stress on functional competence and genomic integrity of human spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXmvFyqu74%3D&md5=91e8e8578921d635ef48c6a0f13021c9CAS | 9780307PubMed |

Barroso, G., Morshedi, M., and Oehninger, S. (2000). Analysis of DNA fragmentation, plasma, membrane translocation of phosphatidylserine and oxidative stress in human spermatozoa. Hum. Reprod. 15, 1338–1344.
Analysis of DNA fragmentation, plasma, membrane translocation of phosphatidylserine and oxidative stress in human spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXksVCluro%3D&md5=9847f0b159d34d6f7c996a7a7cf83ed9CAS | 10831565PubMed |

Baumber, J., Ball, B. A., Linfor, J. L., and Meyers, S. A. (2003). Reactive oxygen species and cryopreservation promote DNA fragmentation in equine spermatozoa. J. Androl. 24, 2621–2628.

Brüssow, K., Torner, H., Ratky, J., Manabe, N., and Tuchscherer, A. (2006). Experimental evidence for the influence of cumulus-oocyte-complexes on sperm release from the porcine oviductal sperm reservoir. J. Reprod. Dev. 52, 249–257.
Experimental evidence for the influence of cumulus-oocyte-complexes on sperm release from the porcine oviductal sperm reservoir.Crossref | GoogleScholarGoogle Scholar | 16428862PubMed |

De Iuliis, G. N., Newey, R. J., King, B. V., and Aitken, R. J. (2009). Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro. PLoS ONE 4, e6446.
Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro.Crossref | GoogleScholarGoogle Scholar | 19649291PubMed |

Donnelly, E. T., McClure, N., and Lewis, S. E. M. (1999). The effect of ascorbate and α-tocopherol supplementation in vitro on DNA integrity and hydrogen peroxide-induced DNA damage in human spermatozoa. Mutagenesis 14, 505–512.
The effect of ascorbate and α-tocopherol supplementation in vitro on DNA integrity and hydrogen peroxide-induced DNA damage in human spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXmtlOjt74%3D&md5=44433c7876fcf0844e860309029ec9edCAS | 10473655PubMed |

El Mouatassim, S., Guérin, P., and Ménézo, Y. (2000). Mammalian oviduct and protection against free oxygen radicals: expression of genes encoding antioxidant enzymes in human and mouse. Eur. J. Obstet. Gynecol. Reprod. Biol. 89, 1–6.
Mammalian oviduct and protection against free oxygen radicals: expression of genes encoding antioxidant enzymes in human and mouse.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXht1Kqur4%3D&md5=f4ef066780484f7785942ec0b5100e3dCAS | 10733016PubMed |

Ellington, J. E., Jones, A. E., Davitt, C. M., Schneider, C. S., Brisbois, R. S., Hiss, G. A., and Wright, R. W. (1998). Human sperm function in co-culture with human, macaque or bovine oviduct epithelial cell monolayers. Hum. Reprod. 13, 2797–2804.
| 1:STN:280:DyaK1M%2FhvFekug%3D%3D&md5=7b2dbf700d61e523e9c847dde181d6a4CAS | 9804233PubMed |

Fatehi, A. N., Bevers, M. M., Schoevers, E., Roelen, B. A., Colenbrander, B., and Gadella, B. M. (2006). DNA damage in bovine sperm does not block fertilization and early embryonic development but induces apoptosis after the first cleavages. J. Androl. 27, 176–188.
DNA damage in bovine sperm does not block fertilization and early embryonic development but induces apoptosis after the first cleavages.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xit12jtb0%3D&md5=c33ed34b00a8643e1991124c557c76a4CAS | 16304212PubMed |

Fazeli, A., Duncan, A. E., Watson, P. F., and Holt, W. V. (1999). Sperm-oviduct interaction: induction of capacitation and preferential binding of uncapacitated spermatozoa to oviductal epithelial cells in porcine species. Biol. Reprod. 60, 879–886.
Sperm-oviduct interaction: induction of capacitation and preferential binding of uncapacitated spermatozoa to oviductal epithelial cells in porcine species.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXitVGru7k%3D&md5=6f2d978a4dd967afe9b70b319d631834CAS | 10084961PubMed |

Fazeli, A., Elliott, R. M. A., Duncan, A. E., Moore, A., Watson, P. F., and Holt, W. V. (2003). In vitro maintenance of boar sperm viability by a soluble fraction obtained from oviductal apical plasma membrane preparations. Reproduction 125, 509–517.
In vitro maintenance of boar sperm viability by a soluble fraction obtained from oviductal apical plasma membrane preparations.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXjvFOqt7c%3D&md5=9222babbc72e9eb4a9d0c25acc8e2dc8CAS | 12683921PubMed |

Gavella, M., and Lipovac, V. (1992). NADH-dependent oxido-reductase (diaphorase) activity and isozyme pattern of sperm in infertile men. Arch. Androl. 28, 135–141.
NADH-dependent oxido-reductase (diaphorase) activity and isozyme pattern of sperm in infertile men.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38XkvVOqtLs%3D&md5=4ea8b22e44e5b65e026354cdb9d9c471CAS | 1520038PubMed |

Georgiou, A. S., Sostaric, E., Wong, C. H., Snijders, A. P. L., Wright, P. C., Moore, H. D., and Fazeli, A. (2005). Gametes alter the oviductal secretory proteome. Mol. Cell. Proteomics 4, 1785–1796.
Gametes alter the oviductal secretory proteome.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXht1Cgtb%2FK&md5=b884abe229212e9130df8976ff79ae47CAS | 16105986PubMed |

Georgiou, A. S., Snijders, A. P. L., Sostaric, E., Aflatoonian, R., Vazquez, J. L., Vazquez, J. M., Roca, J., Martinez, E. A., Wright, P. C., and Fazeli, A. (2007). Modulation of the oviductal environment by gametes. J. Proteome Res. 6, 4656–4666.
Modulation of the oviductal environment by gametes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtlWmu73O&md5=a4b9912f27eeb7903926a8df65f4ee2cCAS | 18004800PubMed |

Gomez, E., Buckingham, D. W., Brindle, J., Lanzafame, F., Irvine, D. S., and Aitken, R. J. (1996). Development of an image analysis system to monitor the retention of residual cytoplasm by human spermatozoa: correlation with biochemical markers of the cytoplasmic space, oxidative stress, and sperm function. J. Androl. 17, 276–287.
| 1:STN:280:DyaK28zosVegsg%3D%3D&md5=160e94dd2164785a8c83c8bff695c8d4CAS | 8792218PubMed |

Gualtieri, R., and Talevi, R. (2000). In vitro-cultured bovine oviductal cells bind acrosome-intact sperm and retain this ability upon sperm release Biol. Reprod. 62, 1754–1762.
In vitro-cultured bovine oviductal cells bind acrosome-intact sperm and retain this ability upon sperm releaseCrossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXjsF2hsbk%3D&md5=a10cf5e291abb64a403e8b67b83cf830CAS | 10819780PubMed |

Gualtieri, R., Boni, R., Tosti, E., Zagami, M., and Talevi, R. (2005). Intracellular calcium and protein tyrosine phosphorylation during the release of bovine sperm adhering to the fallopian tube epithelium in vitro. Reproduction 129, 51–60.
Intracellular calcium and protein tyrosine phosphorylation during the release of bovine sperm adhering to the fallopian tube epithelium in vitro.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXht1eltbo%3D&md5=12046701c16890fd1c54e0c4af83167eCAS | 15615898PubMed |

Harper, M. J. K. (1973). Relationship between sperm transport and penetration of eggs in the rabbit oviduct. Biol. Reprod. 8, 441–450.
| 1:STN:280:DyaE3s7psFeqtA%3D%3D&md5=5d793e4278b881f1ed19f26686d9164bCAS |

Henkel, R., Kierspel, E., Stalf, T., Mehnert, C., Menkveld, R., Tinneberg, H. R., Schill, W. B., and Kruger, T. F. (2005). Effect of reactive oxygen species produced by spermatozoa and leukocytes on sperm functions in non-leukocytospermic patients. Fertil. Steril. 83, 635–642.
Effect of reactive oxygen species produced by spermatozoa and leukocytes on sperm functions in non-leukocytospermic patients.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXjtVOksrg%3D&md5=4c3ca9320a863213e84b6eb26f5a71cfCAS | 15749492PubMed |

Hunter, R. H. F. (1984). Pre-ovulatory arrest and peri-ovulatory redistribution of competent spermatozoa in the isthmus of the pig oviduct. J. Reprod. Fertil. 72, 203–211.
Pre-ovulatory arrest and peri-ovulatory redistribution of competent spermatozoa in the isthmus of the pig oviduct.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaL2c3pt1Wrsw%3D%3D&md5=c9ff9683398e60f309a312ba19f723a1CAS |

Hunter, R. H. F. (2005). The fallopian tubes in domestic mammals: how vital is their physiological activity? Reprod. Nutr. Dev. 45, 281–290.
The fallopian tubes in domestic mammals: how vital is their physiological activity?Crossref | GoogleScholarGoogle Scholar |

Hunter, R. H. F., and Nichol, R. (1983). Transport of spermatozoa in the sheep oviduct: preovulatory sequestering of cells in the caudal isthmus. J. Exp. Zool. 228, 121–128.
Transport of spermatozoa in the sheep oviduct: preovulatory sequestering of cells in the caudal isthmus.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaL2c7htlCjtw%3D%3D&md5=17acf35e67299f353023a31dff35ceabCAS |

Hunter, R. H. F., and Wilmut, I. (1984). Sperm transport in the cow: peri-ovulatory redistribution of viable cells within the oviduct. Reprod. Nutr. Dev. 24, 597–608.
Sperm transport in the cow: peri-ovulatory redistribution of viable cells within the oviduct.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaL2M%2FovFKgug%3D%3D&md5=ffd58d844fb8503073fe0b4b9d1b7aadCAS |

Kadirvel, G., Kumara, S., and Kumaresan, A. (2009). Lipid peroxidation, mitochondrial membrane potential and DNA integrity of spermatozoa in relation to intracellular reactive oxygen species in liquid and frozen-thawed buffalo semen. Anim. Reprod. Sci. 114, 125–134.
Lipid peroxidation, mitochondrial membrane potential and DNA integrity of spermatozoa in relation to intracellular reactive oxygen species in liquid and frozen-thawed buffalo semen.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXms1yqu7Y%3D&md5=628eca6fa89eb75466c8169238a3d949CAS | 19010614PubMed |

Kasai, H. (2002). Chemistry-based studies on oxidative DNA damage: formation, repair, and mutagenesis. Free Radic. Biol. Med. 33, 450–456.
Chemistry-based studies on oxidative DNA damage: formation, repair, and mutagenesis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XlvVWmtbo%3D&md5=b261ee91d74017e4956b5578d32f56b2CAS | 12160927PubMed |

Killian, G. J. (2004). Evidence for the role of oviduct secretions in sperm function, fertilization and embryo development. Anim. Reprod. Sci. 82–83, 141–153.
Evidence for the role of oviduct secretions in sperm function, fertilization and embryo development.Crossref | GoogleScholarGoogle Scholar | 15271449PubMed |

Lapointe, J., and Bilodeau, J. (2003). Antioxidant defenses are modulated in the cow oviduct during the estrous cycle. Biol. Reprod. 68, 1157–1164.
Antioxidant defenses are modulated in the cow oviduct during the estrous cycle.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXisVert7o%3D&md5=be7a8c544d7e673ab3905969924add41CAS | 12606442PubMed |

Lapointe, J., Kimmins, S., MacLaren, L. A., and Bilodeau, J. (2005). Estrogen selectively up-regulates the phospholipid hydroperoxide glutathione peroxidase in the oviducts. Endocrinology 146, 2583–2592.
Estrogen selectively up-regulates the phospholipid hydroperoxide glutathione peroxidase in the oviducts.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXksleiur8%3D&md5=2b391c709df6cda93cd0aa308db09a91CAS | 15746255PubMed |

Lefebvre, R., and Suarez, S. S. (1996). Effect of capacitation on bull sperm binding to homologous oviductal epithelium. Biol. Reprod. 54, 575–582.
Effect of capacitation on bull sperm binding to homologous oviductal epithelium.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK28XhtFCjt7s%3D&md5=50629265f674d39d17880e060ae60af6CAS | 8835378PubMed |

Lopes, S., Jurisicova, A., Sun, J. G., and Casper, R. F. (1998). Reactive oxygen species: potential use for DNA fragmentation in human spermatozoa. Hum. Reprod. 13, 896–900.
Reactive oxygen species: potential use for DNA fragmentation in human spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXjs12gtbo%3D&md5=43f062c3442d970b13e1fda1f21b6fc6CAS | 9619544PubMed |

Murray, S., and Smith, T. T. (1997). Sperm interaction with fallopian tube apical membrane enhances sperm motility and delays capacitation. Fertil. Steril. 68, 351–357.
Sperm interaction with fallopian tube apical membrane enhances sperm motility and delays capacitation.Crossref | GoogleScholarGoogle Scholar | 9240269PubMed |

Navarrete Gómez, P., Espinoza Ruiz, J., Parodi Rivera, J., Alvarez, J. G., and Sánchez Gutiérrez, R. (2009). Protective effect of fallopian tubal fluid against activated leukocyte-induced sperm DNA fragmentation: preliminary results. Andrologia 41, 196–198.
Protective effect of fallopian tubal fluid against activated leukocyte-induced sperm DNA fragmentation: preliminary results.Crossref | GoogleScholarGoogle Scholar | 19400855PubMed |

Parrish, J. J., Susko-Parrish, J., Winer, M. A., and First, N. L. (1988). Capacitation of bovine sperm by heparin. Biol. Reprod. 38, 1171–1180.
Capacitation of bovine sperm by heparin.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1cXkslWit7g%3D&md5=f45cbc9d70f88613dedbf00729038d72CAS | 3408784PubMed |

Peris, S. I., Bilodeau, J., Dufour, M., and Bailey, J. L. (2007). Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm. Mol. Reprod. Dev. 74, 878–892.
Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXmtlKlsbc%3D&md5=d0509c4073376be15ee6cf4d00f500feCAS | 17186553PubMed |

Petrunkina, A. M., Gehlhaar, R., Drommer, W., Waberski, D., and Töpfer-Petersen, E. (2001). Selective sperm binding to pig oviductal epithelium in vitro. Reproduction 121, 889–896.
Selective sperm binding to pig oviductal epithelium in vitro.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXkslWntr0%3D&md5=443a58e7c0a84b1003d32daaf7763acdCAS | 11373175PubMed |

Petrunkina, A. M., Friedrich, J., Drommer, W., Bicker, G., Waberski, D., and Töpfer-Petersen, E. (2001a). Kinetic characterization of the changes in protein tyrosine phosphorylation of membranes, cytosolic Ca2+ concentration and viability in boar sperm populations selected by binding to oviductal ephitelial cells. Reproduction 122, 469–480.
Kinetic characterization of the changes in protein tyrosine phosphorylation of membranes, cytosolic Ca2+ concentration and viability in boar sperm populations selected by binding to oviductal ephitelial cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXntVGksbY%3D&md5=64fd11a090d3a21a846124568e6e07f9CAS | 11597312PubMed |

Revah, I., Gadella, B. M., Flesch, F. M., Colenbrander, B., and Suarez, S. S. (2000). Physiological state of sperm affects fucose and mannose-binding properties. Biol. Reprod. 62, 1010–1015.
Physiological state of sperm affects fucose and mannose-binding properties.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXitFajtLY%3D&md5=7d412818fda7d92f116fdd2b21e341c2CAS | 10727271PubMed |

Robert, C., Caille, A., Zumoffen, C., Cabada, M., and Ghersevich, S. (2008). Effect of human oviductal in vitro secretion on human sperm DNA integrity. J. Assist. Reprod. Genet. 25, 263–270.
Effect of human oviductal in vitro secretion on human sperm DNA integrity.Crossref | GoogleScholarGoogle Scholar | 18581226PubMed |

Said, T. M., Agarwal, A., Sharma, R. K., Thomas, A. J., and Sikka, S. C. (2005). Impact of sperm morphology on DNA damage caused by oxidative stress induced by beta-nicotinamide adenine dinucleotide phosphate. Fertil. Steril. 83, 95–103.
Impact of sperm morphology on DNA damage caused by oxidative stress induced by beta-nicotinamide adenine dinucleotide phosphate.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXisVOqs78%3D&md5=41db2c2f6666e931a2614c004261a6ccCAS | 15652893PubMed |

Sikka, S. C. (2001). Relative impact of oxidative stress on male reproductive function. Curr. Med. Chem. 8, 851–862.
| 1:CAS:528:DC%2BD3MXjsVChuro%3D&md5=a8004d96b5a0157ab3a3942fadb74cadCAS | 11375755PubMed |

Sostaric, E., van de Lest, C. H. A., Colenbrander, B., and Gadella, B. M. (2005). Dynamics of carbohydrate affinities at the cell surface of capacitating bovine sperm cells. Biol. Reprod. 72, 346–357.
Dynamics of carbohydrate affinities at the cell surface of capacitating bovine sperm cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXptFGmuw%3D%3D&md5=e15586152a2cc1b95e1f39eec97ee9b8CAS | 15456700PubMed |

Sostaric, E., Georgiou, A. S., Wong, C. H., Watson, P. F., Holt, W. V., and Fazeli, A. (2006). Global profiling of surface plasma membrane proteome of oviductal epithelial cells. J. Proteome Res. 5, 3029–3037.
Global profiling of surface plasma membrane proteome of oviductal epithelial cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhtVyrsbfN&md5=a37d2313bc659db12e5070bf2eb98631CAS | 17081054PubMed |

Suarez, S. S. (2002). Formation of a reservoir of sperm in the oviduct. Reprod. Domest. Anim. 37, 140–143.
Formation of a reservoir of sperm in the oviduct.Crossref | GoogleScholarGoogle Scholar | 12071887PubMed |

Talevi, R., and Gualtieri, R. (2001). Sulfated glycoconjugates are powerful modulators of bovine sperm adhesion and release from the oviductal epithelium in vitro. Biol. Reprod. 64, 491–498.
Sulfated glycoconjugates are powerful modulators of bovine sperm adhesion and release from the oviductal epithelium in vitro.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXnsVKqtg%3D%3D&md5=ace211e0292342e99a869e0ae9b0fa6fCAS | 11159351PubMed |

Thomas, P. G. A., Ball, B. A., and Brinsko, S. P. (1994). Interaction of equine spermatozoa with oviduct epithelial cell explants is affected by estrous cycle and anatomic origin of explants. Biol. Reprod. 51, 222–228.
Interaction of equine spermatozoa with oviduct epithelial cell explants is affected by estrous cycle and anatomic origin of explants.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK2M%2FjsFGltA%3D%3D&md5=04f1cd49d08b8bfa14a6bc9495b45915CAS |

Twigg, J. P., Irvine, D. S., and Aitken, R. J. (1998). Oxidative damage to DNA in human spermatozoa does not preclude pronucleus formation at intracytoplasmic sperm injection. Hum. Reprod. 13, 1864–1871.
Oxidative damage to DNA in human spermatozoa does not preclude pronucleus formation at intracytoplasmic sperm injection.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXls1Kqsb4%3D&md5=70b90f12f5d69972e2064fbf1c3e7a58CAS | 9740440PubMed |

Yanagimachi, R., and Chang, M. C. (1963). Fertilization of hamster eggs in vitro. Nature 200, 281–282.
Fertilization of hamster eggs in vitro.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaF2c%2Fkt1Ohsw%3D%3D&md5=195b707e4c3b34f7e2f6759e68e3e5b7CAS | 14085061PubMed |