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

Bovine spermatozoa react to in vitro heat stress by activating the mitogen-activated protein kinase 14 signalling pathway

Mohammad Bozlur Rahman A E , Leen Vandaele B , Tom Rijsselaere A , Mohamed Shehab El-Deen C , Dominiek Maes A , Mohammed Shamsuddin D and Ann Van Soom A
+ Author Affiliations
- Author Affiliations

A Department of Reproduction, Obstetrics and Herd Health, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.

B Department of Animal Science, Institute for Agricultural and Fisheries Research, Scheldeweg 68, 9090 Melle, Belgium.

C Department of Animal Production, Suez Canal University, Ismailia 41522, Egypt.

D Department of Surgery and Obstetrics, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.

E Corresponding author. Email: mohammadbozlur.rahman@ugent.be

Reproduction, Fertility and Development 26(2) 245-257 https://doi.org/10.1071/RD12198
Submitted: 22 June 2012  Accepted: 27 November 2012   Published: 18 January 2013

Abstract

Heat stress has long been recognised as a cause of subfertility in farm animals. The objectives of the present study were to elucidate the effect of heat stress on sperm function and involvement of the mitogen-activated protein kinase (MAPK) 14 signalling pathway. Spermatozoa incubated for 4 h at a physiological temperature (38.5°C) exhibited significantly (P < 0.05) reduced motility, plasma membrane integrity and mitochondrial potential compared with non-incubated spermatozoa; the reductions in these parameters were more severe following incubation at a hyperthermic (41°C) temperature (P < 0.01). Percentages of fertilisation and embryo development were highly affected in spermatozoa incubated at 41°C compared with non-incubated spermatozoa (P < 0.01). Similarly, embryo quality was adversely affected by sperm incubation at 41°C, as indicated by a higher apoptotic cell ratio in Day 7 blastocysts compared with that in the non-incubated control group (14.6% vs 6.7%, respectively; P < 0.01). Using SB203580 (10 µg mL–1), a specific inhibitor of the p38 MAPK pathway, during sperm hyperthermia reduced MAPK14 activation (24.9% vs 35.6%), increased sperm motility (45.8% vs 26.5%) and reduced DNA fragmentation (16.9% vs 23.4%) compared with the untreated control group, but did not improve subsequent fertilisation and embryo development. In conclusion, heat stress significantly affects the potential of spermatozoa to penetrate oocytes, as well as subsequent embryo development and quality. Notably, the data show that the MAPK14 signalling pathway is largely involved in heat-induced sperm damage. However, further research is needed to elucidate other signalling pathways possibly involved in heat-induced sperm damage.

Additional keywords: functional parameters, mitogen-activated protein kinase 14 phosphorylation, terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling.


References

Almog, T., Lazar, S., Reiss, N., Etkovitz, N., Milch, E., Rahamim, N., Dobkin-Bekman, M., Rotem, R., Kalina, M., Ramon, J., Raziel, A., Brietbart, H., Seger, R., and Naor, Z. (2008). Identification of extracellular signal-regulated kinase 1/2 and p38 MAPK as regulators of human sperm motility and acrosome reaction and as predictors of poor spermatozoan quality. J. Biol. Chem. 283, 14 479–14 489.
Identification of extracellular signal-regulated kinase 1/2 and p38 MAPK as regulators of human sperm motility and acrosome reaction and as predictors of poor spermatozoan quality.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXlvFyjsL4%3D&md5=395b91768a5682e49197c2d1e48622ccCAS |

Aquila, S., Middea, E., Catalano, S., Marsico, S., Lanzino, M., Casaburi, I., Barone, I., Bruno, R., Zupo, S., and Ando, S. (2007). Human sperm express a functional androgen receptor: effects on PI3K/AKT pathway. Hum. Reprod. 22, 2594–2605.
Human sperm express a functional androgen receptor: effects on PI3K/AKT pathway.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtlektrfL&md5=80f6d1dcf64a32c47f77c51ddda32275CAS | 17656415PubMed |

Aziz, N., Said, T., Paasch, U., and Agarwal, A. (2007). The relationship between human sperm apoptosis, morphology and the sperm deformity index. Hum. Reprod. 22, 1413–1419.
The relationship between human sperm apoptosis, morphology and the sperm deformity index.Crossref | GoogleScholarGoogle Scholar | 17303629PubMed |

Ball, B. A. (2008). Oxidative stress, osmotic stress and apoptosis: impacts on sperm function and preservation in the horse. Anim. Reprod. Sci. 107, 257–267.
Oxidative stress, osmotic stress and apoptosis: impacts on sperm function and preservation in the horse.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXoslWkt7c%3D&md5=dfb645a2a5bdabf5a754a24c6c4ec5dfCAS | 18524506PubMed |

Ball, B. A., and Vo, A. (2001). Osmotic tolerance of equine spermatozoa and the effects of soluble cryoprotectants on equine sperm motility, viability, and mitochondrial membrane potential. J. Androl. 22, 1061–1069.
| 1:CAS:528:DC%2BD3MXotlyns7o%3D&md5=cea610611fb5b51f38c4502dd243e644CAS | 11700853PubMed |

Bejarano, I., Lozano, G. M., Ortiz, A., Garcia, J. F., Paredes, S. D., Rodriguez, A. B., and Pariente, J. A. (2008). Caspase 3 activation in human spermatozoa in response to hydrogen peroxide and progesterone. Fertil. Steril. 90, 1340–1347.
Caspase 3 activation in human spermatozoa in response to hydrogen peroxide and progesterone.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXhtlSrurbK&md5=07faf01885a2aa5fd3ffa4959bf55c6fCAS | 18155705PubMed |

Bellmann, K., Charette, S. J., Nadeau, P. J., Poirier, D. J., Loranger, A., and Landry, J. (2010). The mechanism whereby heat shock induces apoptosis depends on the innate sensitivity of cells to stress. Cell Stress Chaperones 15, 101–113.
The mechanism whereby heat shock induces apoptosis depends on the innate sensitivity of cells to stress.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhsFaqt73E&md5=bb88ee892c7c6a9b6b5924e2788c0712CAS | 19557548PubMed |

Blaquier, J. A., Cameo, M. S., Cuasnicu, P. S., Gonzalez Echeverria, M. F., Pineiro, L., and Tezon, J. G. (1988a). The role of epididymal factors in human sperm fertilizing ability. Ann. N. Y. Acad. Sci. 541, 292–296.
The role of epididymal factors in human sperm fertilizing ability.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXovVOisQ%3D%3D&md5=76d305460084050574d90191efe53f88CAS | 3195912PubMed |

Blaquier, J. A., Cameo, M. S., Cuasnicu, P. S., Gonzalez Echeverria, M. F., Pineiro, L., Tezon, J. G., and Vazquez, M. H. (1988b). On the role of epididymal factors in sperm fertility. Reprod. Nutr. Dev. 28, 1209–1216.
On the role of epididymal factors in sperm fertility.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXkt1WitL8%3D&md5=3ff47dc6f0fc95f125e56e705246cad7CAS | 3075792PubMed |

Brouwers, J. F. H. M., and Gadella, B. M. (2003). In situ detection and localization of lipid peroxidation in individual bovine sperm cells. Free Radic. Biol. Med. 35, 1382–1391.
In situ detection and localization of lipid peroxidation in individual bovine sperm cells.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXpt1equrg%3D&md5=9fd99b3ee3cfc51cbe921bd5967a8137CAS |

Brum, A. M., Sabeur, K., and Ball, B. A. (2008). Apoptotic-like changes in equine spermatozoa separated by density-gradient centrifugation or after cryopreservation. Theriogenology 69, 1041–1055.
Apoptotic-like changes in equine spermatozoa separated by density-gradient centrifugation or after cryopreservation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXlvVSltLo%3D&md5=4358b00e67002e4db814002c2c6ece5fCAS | 18378291PubMed |

Celeghini, E. C., de Arruda, R. P., de Andrade, A. F., Nascimento, J., and Raphael, C. F. (2007). Practical techniques for bovine sperm simultaneous fluorimetric assessment of plasma, acrosomal and mitochondrial membranes. Reprod. Domest. Anim. 42, 479–488.
Practical techniques for bovine sperm simultaneous fluorimetric assessment of plasma, acrosomal and mitochondrial membranes.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2srjtF2qtA%3D%3D&md5=5a3b1a5746e007af1997d3c1b33c37deCAS | 17845603PubMed |

Cowan, K. J., and Storey, K. B. (2003). Mitogen-activated protein kinases: new signaling pathways functioning in cellular responses to environmental stress. J. Exp. Biol. 206, 1107–1115.
Mitogen-activated protein kinases: new signaling pathways functioning in cellular responses to environmental stress.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXjt1aqtb0%3D&md5=0f49627d9d7de9fc98b5f578e484e7baCAS | 12604570PubMed |

de Castro e Paula, L. A., Andrzejewski, J., Julian, D., Spicer, L. J., and Hansen, P. J. (2008). Oxygen and steroid concentrations in preovulatory follicles of lactating dairy cows exposed to acute heat stress. Theriogenology 69, 805–813.
Oxygen and steroid concentrations in preovulatory follicles of lactating dairy cows exposed to acute heat stress.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXktFClsbs%3D&md5=723b0d4616485933d4f54cf41f938710CAS | 18243293PubMed |

de la Cueva, F. I. C., Pujol, M. R., Rigau, T., Bonet, S., Miro, J., Briz, M., and Rodriguez-Gill, J. E. (1997). Resistance to osmotic stress of horse spermatozoa: The role of ionic pumps and their relationship to cryopreservation success. Theriogenology 48, 947–968.
Resistance to osmotic stress of horse spermatozoa: The role of ionic pumps and their relationship to cryopreservation success.Crossref | GoogleScholarGoogle Scholar |

de Lamirande, E., and Gagnon, C. (2002). The extracellular signal-regulated kinase (ERK) pathway is involved in human sperm function and modulated by the superoxide anion. Mol. Hum. Reprod. 8, 124–135.
The extracellular signal-regulated kinase (ERK) pathway is involved in human sperm function and modulated by the superoxide anion.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XitFOgsr8%3D&md5=4eab3a859b6146d5775e6042133e49c7CAS | 11818515PubMed |

Du Plessis, S. S., McAllister, D. A., Luu, A., Savia, J., Agarwal, A., and Lampiao, F. (2010). Effects of H2O2 exposure on human sperm motility parameters, reactive oxygen species levels and nitric oxide levels. Andrologia 42, 206–210.
Effects of H2O2 exposure on human sperm motility parameters, reactive oxygen species levels and nitric oxide levels.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXosF2ls78%3D&md5=d6b350a2ead7c35cba428b8686b29ac6CAS | 20500750PubMed |

Elvinger, F., Natzke, R. P., and Hansen, P. J. (1992). Interactions of heat stress and bovine somatotropin affecting physiology and immunology of lactating cows. J. Dairy Sci. 75, 449–462.
Interactions of heat stress and bovine somatotropin affecting physiology and immunology of lactating cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK38Xht1Wgs7s%3D&md5=62264dfd19f53ce1e05fd9a4e30ddf97CAS | 1560140PubMed |

Engel, J. C., Bernard, E. A., and Wassermann, G. F. (1973). Protein synthesis by isolated spermatozoa from cauda and caput epididymis of rat. Acta Physiol. Lat. Am. 23, 358–362.
| 1:CAS:528:DyaE2cXmvVOhuw%3D%3D&md5=d0596f01fcea1a9337532a07d7d54ee1CAS | 4361620PubMed |

Grunewald, S., Paasch, U., Glander, H. J., and Anderegg, U. (2005). Mature human spermatozoa do not transcribe novel RNA. Andrologia 37, 69–71.
Mature human spermatozoa do not transcribe novel RNA.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXpslGitLo%3D&md5=26686318d054dad0d1d285fb3bd7b227CAS | 16026427PubMed |

Hansen, P. J. (2009). Effects of heat stress on mammalian reproduction. Philos. Trans. R. Soc. Lond. B Biol. Sci. 364, 3341–3350.
Effects of heat stress on mammalian reproduction.Crossref | GoogleScholarGoogle Scholar | 19833646PubMed |

Hendricks, K. E. M., Martins, L., and Hansen, P. J. (2009). Consequences for the bovine embryo of being derived from a spermatozoon subjected to post-ejaculatory aging and heat shock: development to the blastocyst stage and sex ratio. J. Reprod. Dev. 55, 69–74.
Consequences for the bovine embryo of being derived from a spermatozoon subjected to post-ejaculatory aging and heat shock: development to the blastocyst stage and sex ratio.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXktlGgtLw%3D&md5=61928d571702baedc7d3a3aa5162f060CAS |

Hikim, A. P., Lue, Y., Yamamoto, C. M., Vera, Y., Rodriguez, S., Yen, P. H., Soeng, K., Wang, C., and Swerdloff, R. S. (2003). Key apoptotic pathways for heat-induced programmed germ cell death in the testis. Endocrinology 144, 3167–3175.
Key apoptotic pathways for heat-induced programmed germ cell death in the testis.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3sXkvF2ktb4%3D&md5=6e21af1d5c986296be213727b2b1c602CAS | 12810573PubMed |

Ishii, T., Matsuki, S., Iuchi, Y., Okada, F., Toyosaki, S., Tomita, Y., Ikeda, Y., and Fujii, J. (2005). Accelerated impairment of spermatogenic cells in sod1-knockout mice under heat stress. Free Radic. Res. 39, 697–705.
Accelerated impairment of spermatogenic cells in sod1-knockout mice under heat stress.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXltFymurw%3D&md5=3fe9511339d1252534426366781fa270CAS | 16036348PubMed |

Jannes, P., Spiessens, C., Van der Auwera, I., D’Hooghe, T., Verhoeven, G., and Vanderschueren, D. (1998). Male subfertility induced by acute scrotal heating affects embryo quality in normal female mice. Hum. Reprod. 13, 372–375.
Male subfertility induced by acute scrotal heating affects embryo quality in normal female mice.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK1c3hs12hsg%3D%3D&md5=d5b0e62b4348c677a452ae9629bb7734CAS | 9557841PubMed |

Jia, Y., Castellanos, J., Wang, C., Sinha-Hikim, I., Lue, Y., Swerdloff, R. S., and Sinha-Hikim, A. P. (2009). Mitogen-activated protein kinase signaling in male germ cell apoptosis in the rat. Biol. Reprod. 80, 771–780.
Mitogen-activated protein kinase signaling in male germ cell apoptosis in the rat.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXjvVSkur4%3D&md5=d4ae4123a4fdce668689b3db3d5ac418CAS | 19109224PubMed |

Johnson, G. L., and Lapadat, R. (2002). Mitogen-activated protein kinase pathways mediated by ERK, JNK, and p38 protein kinases. Science 298, 1911–1912.
Mitogen-activated protein kinase pathways mediated by ERK, JNK, and p38 protein kinases.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xpt1Wisbc%3D&md5=5d78bf4a79bd3785d151db2879f20b52CAS | 12471242PubMed |

Lechniak, D., Strabel, T., Bousquet, D., and King, A. W. (2003). Sperm pre-incubation prior to insemination affects the sex ratio of bovine embryos produced in vitro. Reprod. Domest. Anim. 38, 224–227.
Sperm pre-incubation prior to insemination affects the sex ratio of bovine embryos produced in vitro.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD3s3ntVyhsA%3D%3D&md5=544e6f89f81bf697d16b5facd679b136CAS | 12753558PubMed |

Madan, P., Calder, M. D., and Watson, A. J. (2005). Mitogen-activated protein kinase (MAPK) blockade of bovine preimplantation embryogenesis requires inhibition of both p38 and extracellular signal-regulated kinase (ERK) pathways. Reproduction 130, 41–51.
Mitogen-activated protein kinase (MAPK) blockade of bovine preimplantation embryogenesis requires inhibition of both p38 and extracellular signal-regulated kinase (ERK) pathways.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXnt1ynsrc%3D&md5=e0d224e28fa9ceafff9b2edbea4d94a0CAS | 15985630PubMed |

Martin, G., Sabido, O., Durand, P., and Levy, R. (2004). Cryopreservation induces an apoptosis-like mechanism in bull sperm. Biol. Reprod. 71, 28–37.
Cryopreservation induces an apoptosis-like mechanism in bull sperm.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXltFKktLo%3D&md5=0bfa42993e74aa5ac9257bc326f97f11CAS | 14973261PubMed |

Martin, G., Cagnon, N., Sabido, O., Sion, B., Grizard, G., Durand, P., and Levy, R. (2007). Kinetics of occurrence of some features of apoptosis during the cryopreservation process of bovine spermatozoa. Hum. Reprod. 22, 380–388.
Kinetics of occurrence of some features of apoptosis during the cryopreservation process of bovine spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXotFCqtA%3D%3D&md5=6a8470ad2fc8239c4dab8e26a7286b34CAS | 17092986PubMed |

Miller, D., Brinkworth, M., and Iles, D. (2010). Paternal DNA packaging in spermatozoa: more than the sum of its parts? DNA, histones, protamines and epigenetics. Reproduction 139, 287–301.
Paternal DNA packaging in spermatozoa: more than the sum of its parts? DNA, histones, protamines and epigenetics.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXitFKit70%3D&md5=bd833c128e192981c35075fd67475bd8CAS | 19759174PubMed |

Mitchell, L. A., De Iuliis, G. N., and Aitken, R. J. (2011). The TUNEL assay consistently underestimates DNA damage in human spermatozoa and is influenced by DNA compaction and cell vitality: development of an improved methodology. Int. J. Androl. 34, 2–13.
The TUNEL assay consistently underestimates DNA damage in human spermatozoa and is influenced by DNA compaction and cell vitality: development of an improved methodology.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXitlehur4%3D&md5=d9e01a63bfb4c6679aa56b7184a54237CAS | 20158539PubMed |

Monterroso, V. H., Drury, K. C., Ealy, A. D., Edwards, J. L., and Hansen, P. J. (1995). Effect of heat shock on function of frozen/thawed bull spermatozoa. Theriogenology 44, 947–961.
Effect of heat shock on function of frozen/thawed bull spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD28zgtVGntQ%3D%3D&md5=882d00040228ae08d16585ea769e415aCAS | 16727790PubMed |

Nichi, M., Bols, P. E., Zuge, R. M., Barnabe, V. H., Goovaerts, I. G., Barnabe, R. C., and Cortada, C. N. (2006). Seasonal variation in semen quality in Bos indicus and Bos taurus bulls raised under tropical conditions. Theriogenology 66, 822–828.
Seasonal variation in semen quality in Bos indicus and Bos taurus bulls raised under tropical conditions.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1cvltVyhsw%3D%3D&md5=040a176e06ffd69963c524b1a5948073CAS | 16529802PubMed |

O’Flaherty, C., de Lamirande, E., and Gagnon, C. (2005). Reactive oxygen species and protein kinases modulate the level of phospho-MEK-like proteins during human sperm capacitation. Biol. Reprod. 73, 94–105.
Reactive oxygen species and protein kinases modulate the level of phospho-MEK-like proteins during human sperm capacitation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXls1Srt7w%3D&md5=e6fe85adf54e7967211cfdac66f52e05CAS | 15772258PubMed |

Ostermeier, G. C., Miller, D., Huntriss, J. D., Diamond, M. P., and Krawetz, S. A. (2004). Reproductive biology: delivering spermatozoan RNA to the oocyte. Nature 429, 154.
Reproductive biology: delivering spermatozoan RNA to the oocyte.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXjvVKgs7k%3D&md5=d27573b76d852218212a93371df9bdf6CAS | 15141202PubMed |

Paul, C., Murray, A. A., Spears, N., and Saunders, P. T. K. (2008). A single, mild, transient scrotal heat stress causes DNA damage, subfertility and impairs formation of blastocysts in mice. Reproduction 136, 73–84.
A single, mild, transient scrotal heat stress causes DNA damage, subfertility and impairs formation of blastocysts in mice.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1cXovVSnsr4%3D&md5=f87e230d3c2be1ce08afb034dbdf6c2bCAS | 18390691PubMed |

Paul, C., Teng, S., and Saunders, P. T. K. (2009). A single, mild, transient scrotal heat stress causes hypoxia and oxidative stress in mouse testes, which induces germ cell death. Biol. Reprod. 80, 913–919.
A single, mild, transient scrotal heat stress causes hypoxia and oxidative stress in mouse testes, which induces germ cell death.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXlsVWqu7s%3D&md5=d171156e870b8493ccea90740fc1dfccCAS | 19144962PubMed |

Pollard, J. W., Plante, C., King, W. A., Hansen, P. J., Betteridge, K. J., and Suarez, S. S. (1991). Fertilizing-capacity of bovine sperm may be maintained by binding to oviductal epithelial-cells. Biol. Reprod. 44, 102–107.
Fertilizing-capacity of bovine sperm may be maintained by binding to oviductal epithelial-cells.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DyaK3M7pvVemug%3D%3D&md5=3139b1fd7063eeb14b4edbd61acffaf1CAS | 2015341PubMed |

Rahman, M. B., Vandaele, L., Rijsselaere, T., Maes, D., Hoogewijs, M., Frijters, A., Noordman, J., Granados, A., Dernelle, E., Shamsuddin, M., Parrish, J. J., and Van Soom, A. (2011). Scrotal insulation and its relationship to abnormal morphology, chromatin protamination and nuclear shape of spermatozoa in Holstein-Friesian and Belgian blue bulls. Theriogenology 76, 1246–1257.
Scrotal insulation and its relationship to abnormal morphology, chromatin protamination and nuclear shape of spermatozoa in Holstein-Friesian and Belgian blue bulls.Crossref | GoogleScholarGoogle Scholar | 21777969PubMed |

Rahman, M. B., Vandaele, L., Rijsselaere, T., Zhandi, M., Maes, D., Shamsuddin, M., and Van Soom, A. (2012). Oocyte quality determines bovine embryo development after fertilisation with hydrogen peroxide-stressed spermatozoa. Reprod. Fertil. Dev. 24, 608–618.
Oocyte quality determines bovine embryo development after fertilisation with hydrogen peroxide-stressed spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XmtVKitbc%3D&md5=8691f515223406ce595005866b711515CAS | 22541549PubMed |

Said, T. M., Agarwal, A., Zborowski, M., Grunewald, S., Glander, H. J., and Paasch, U. (2008). Utility of magnetic cell separation as a molecular sperm preparation technique. J. Androl. 29, 134–142.
Utility of magnetic cell separation as a molecular sperm preparation technique.Crossref | GoogleScholarGoogle Scholar | 18077822PubMed |

Shaha, C. (2007). Modulators of spermatogenic cell survival. Soc. Reprod. Fertil. Suppl. 63, 173–186.
| 1:CAS:528:DC%2BD1cXpvVykt78%3D&md5=3aa9d8e83bdbce894c3db3bc7c7b0a9bCAS | 17566272PubMed |

Silva, P. F., Gadella, B. M., Colenbrander, B., and Roelen, B. A. (2007). Exposure of bovine sperm to pro-oxidants impairs the developmental competence of the embryo after the first cleavage. Theriogenology 67, 609–619.
Exposure of bovine sperm to pro-oxidants impairs the developmental competence of the embryo after the first cleavage.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXitlyqug%3D%3D&md5=46c1baec04c5ff3dac99a539e1e18821CAS | 17056104PubMed |

Steger, K., Cavalcanti, M. C. O., and Schuppe, H. C. (2011). Prognostic markers for competent human spermatozoa: fertilizing capacity and contribution to the embryo. Int. J. Androl. 34, 513–527.
Prognostic markers for competent human spermatozoa: fertilizing capacity and contribution to the embryo.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XivFOgtr4%3D&md5=b44a48d7dda6a55d3720123128d12a08CAS | 21128979PubMed |

Sutovsky, P., and Schatten, G. (1999). Paternal contributions to the mammalian zygote: fertilization after sperm-egg fusion. Int. Rev. Cytol. 195, 1–65.
Paternal contributions to the mammalian zygote: fertilization after sperm-egg fusion.Crossref | GoogleScholarGoogle Scholar |

Thys, M., Vandaele, L., Morrell, J. M., Mestach, J., Van Soom, A., Hoogewijs, M., and Rodriguez-Martinez, H. (2009). In vitro fertilizing capacity of frozen-thawed bull spermatozoa selected by single-layer (glycidoxypropyltrimethoxysilane) silane-coated silica colloidal centrifugation. Reprod. Domest. Anim. 44, 390–394.
In vitro fertilizing capacity of frozen-thawed bull spermatozoa selected by single-layer (glycidoxypropyltrimethoxysilane) silane-coated silica colloidal centrifugation.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD1MrisFWhtA%3D%3D&md5=bc2f6c81ef11ab658999fb68e8b9fa12CAS | 18992094PubMed |

Vandaele, L., Mateusen, B., Maes, D., de Kruif, A., and Van Soom, A. (2006). Is apoptosis in bovine in vitro produced embryos related to early developmental kinetics and in vivo bull fertility? Theriogenology 65, 1691–1703.
Is apoptosis in bovine in vitro produced embryos related to early developmental kinetics and in vivo bull fertility?Crossref | GoogleScholarGoogle Scholar | 16280159PubMed |

Vandaele, L., Thys, M., Bijttebier, J., Van Langendonckt, A., Donnay, I., Maes, D., Meyer, E., and Van Soom, A. (2010). Short-term exposure to hydrogen peroxide during oocyte maturation improves bovine embryo development. Reproduction 139, 505–511.
Short-term exposure to hydrogen peroxide during oocyte maturation improves bovine embryo development.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXjtV2lsb8%3D&md5=f4c23f42b48145bb0c179246c5896758CAS | 19939885PubMed |

Wada, T., and Penninger, J. M. (2004). Mitogen-activated protein kinases in apoptosis regulation. Oncogene 23, 2838–2849.
Mitogen-activated protein kinases in apoptosis regulation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXivFKmsb8%3D&md5=d7e76f07f58dede7f14d0ce93804316bCAS | 15077147PubMed |

Walters, A. H., Eyestone, W. E., Saacke, R. G., Pearson, R. E., and Gwazdauskas, F. C. (2005a). Bovine embryo development after IVF with spermatozoa having abnormal morphology. Theriogenology 63, 1925–1937.
Bovine embryo development after IVF with spermatozoa having abnormal morphology.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2M7ptFKqtw%3D%3D&md5=37a2be8eb7da634cc1ba464acad481c6CAS | 15823349PubMed |

Walters, A. H., Saacke, R. G., Pearson, R. E., and Gwazdauskas, F. C. (2005b). The incidence of apoptosis after IVF with morphologically abnormal bovine spermatozoa. Theriogenology 64, 1404–1421.
The incidence of apoptosis after IVF with morphologically abnormal bovine spermatozoa.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BD2Mvntl2htQ%3D%3D&md5=fd0375bf74cfcc62a80beecb63186246CAS | 15893815PubMed |

Ward, W. S. (2010). Function of sperm chromatin structural elements in fertilization and development. Mol. Hum. Reprod. 16, 30–36.
Function of sperm chromatin structural elements in fertilization and development.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXhsFOhtrrI&md5=94e9a74eb1960db83f6334a1f838a2a0CAS | 19748904PubMed |