New insights into the mechanisms of fertilization: comparison of the fertilization steps, composition, and structure of the zona pellucida between horses and pigs.
The mechanism of fertilization remains largely enigmatic in mammals. Most studies exploring the molecular mechanism underlying fertilization have been restricted to a single species, generally the mouse, without a comparative approach. However, the identification of divergences between species could allow us to highlight key components in the mechanism of fertilization. In the pig, in vitro fertilization (IVF) and polyspermy rates are high, and spermatozoa penetrate easily through the zona pellucida (ZP). In contrast, IVF rates are low in the horse, and polyspermy is scarce. Our objective was to develop a comparative strategy between these two divergent models. First, we compared the role of equine and porcine gametes in the following five functions using intraspecific and interspecific IVF: ZP binding, acrosome reaction, penetration through the ZP, gamete fusion, and pronucleus formation. Under in vitro conditions, we showed that the ZP is a determining element in sperm-ZP attachment and penetration, whereas the capacity of the spermatozoa is of less importance. In contrast, the capacity of the spermatozoa is a key component of the acrosome reaction step. Second, we compared the composition and structure of the equine and porcine ZP. We observed differences in the number and localization of the ZP glycoproteins and in the mesh-like structure of the ZP between equine and porcine species. These differences might correlate with the differences in spermatozoal attachment and penetration rates. In conclusion, our comparative approach allows us to identify determining elements in the mechanism of fertilization.
Mugnier
Sylvie
S
Institut National de la Recherche Agronomique, UMR85, Physiologie de la Reproduction et des Comportements, Nouzilly, France.
Dell'Aquila
Maria Elena
ME
Pelaez
Jesus
J
Douet
Cécile
C
Ambruosi
Barbara
B
De Santis
Teresa
T
Lacalandra
Giovanni Michele
GM
Lebos
Claude
C
Sizaret
Pierre-Yves
PY
Delaleu
Bernadette
B
Monget
Philippe
P
Mermillod
Pascal
P
Magistrini
Michèle
M
Meyers
Stuart A
SA
Goudet
Ghylène
G
D000818:Animals; D004527:Egg Proteins / Q000378:metabolism; D005260:Female; D005307:Fertilization in Vitro; D006736:Horses / Q000502:physiology*; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission; D009865:Oocytes / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000378:metabolism; D013075:Sperm Capacitation; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology*; D013552:Swine / Q000502:physiology*; D015044:Zona Pellucida / Q000502:physiology*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D000072216:Zona Pellucida Glycoproteins