Current Concepts of Molecular Events During Bovine and Porcine Spermatozoa Capacitation

Abstract

Spermatozoa are required to undergo the processes of capacitation before they obtain fertilizing ability. The molecular changes of capacitation are still not fully understood. However, it is accepted that capacitation is a sequential process involving numerous physiological changes including destabilization of the plasma membrane, alterations of intracellular ion concentrations and membrane potential, and protein phosphorylation. There are no known morphological changes that occur to the spermatozoon during capacitation. The purpose of this review is to summarize current evidence on the molecular aspects of capacitation both in vivo and in vitro in bovine and porcine spermatozoa. For the purpose of this review, the process of sperm capacitation will encompass maturational events that occur following ejaculation up to binding to the zona pellucida, that triggers acrosomal exocytosis and initiates fertilization.

Biochemical and binding characteristics of boar epididymal fluid proteins

“…We studied the changes in the binding ability of epididymal spermatozoa to biotin-labeled heparin, hyaluronic acid, and glycoproteins of zona pellucida (gpZP). Heparin and hyaluronan are present in the lumen of mammalian oviduct as a part of glycosaminoglycans and contribute to the sperm capacitation [27,28]. Proteins attached to the sperm surface during the transit through the epididymis could affect the sperm-binding ability and play a role in successful realization of the reproductive process.…”

Sperm volumetric dynamics during in vitro capacitation process in bovine spermatozoa

“…Thus, heparin in bovine sperm is crucial for the final biophysical mechanism of fusion between the plasma membrane and the outer acrosomal membrane, and as a consequence the loss of cell volume at the final stage of acrosome reaction (Vadnais et al, 2007). In bovine-capacitated sperm, there were no significant changes in cell volume compared with non-capacitated sperm even after exposure to BSA, which is commonly used to mediate sterol efflux (Ehrenwald et al, 1988).…”

Comparative Studies on the Aggregation Behavior of HBPs from Human Seminal Plasma by Dynamic Light Scattering

“…Heparin and high-density lipoproteins stimulates sperm capacitation in the female reproductive tract, although very little information is available which deals with the exact mechanism of sperm capacitation. This is the process by which a spermatozoon becomes capable of fertilizing an ovum after it reaches the ampullary portion of the uterine tube [21,25].…”