Seminal Plasma Proteins and Sperm Resistance to Stress

Abstract

The role of seminal plasma (SP) in mammalian sperm function remains largely a matter of speculation as both inhibitory and stimulating effects have been found. Specific components of SP, particularly proteins, are adsorbed onto the surface of ejaculated sperm as they pass through the male and female reproductive tracts. These sperm coating components seem to have the important function of maintaining the stability of the membrane up to the process of capacitation (decapacitation factors). Therefore, they must be removed, modified or masked before the spermatozoa undergo the acrosome reaction, an essential process for successful fertilization. It is well known that low temperatures alter the function of spermatozoa. Cold shock results in the destabilization of sperm membranes and impairment of sperm function, and it is also well known that ram spermatozoa are more sensitive to cold-shock stress than those of other species. The addition of SP proteins to spermatozoa before and/or after cooling is able to minimize cryoinjury effects. The major proteins in ram SP which are able to protect and repair the cold-shock damage to sperm contain fibronectin-II domains. The significance of this domain and the role of these proteins in sperm capacitation and gamete interaction are discussed.

Sperm surface changes and physiological consequences induced by sperm handling and storage

“…As outlined above, seminal plasma proteins are well known to protect ram spermatozoa from cold shock (cooled or frozen in the absence of cryoprotectants) or during routine freezing (for review, see Maxwell et al (2007) and Muino-Blanco et al (2008)). The main protective components were reported to be a 14 kDa BSP protein, which was shown to prevent (Barrios et al 2005) or reverse (Barrios et al 2000) cold shock damage.…”

Management Factors Affecting Fertility in Sheep

“…In the ram, as in other mammals, there is a loss of semen quality when cooled semen samples are used for assisted reproduction. Cooled semen undergoes a decrease in sperm quality, which includes reduction in motility, destabilisation of sperm membranes and DNA integrity impairment of sperm function Muiño-Blanco et al, 2008). It is well known that ram spermatozoa are more sensitive to coldshock stress than those of other species (Muiño-Blanco et al, 2008).…”

“…Cooled semen undergoes a decrease in sperm quality, which includes reduction in motility, destabilisation of sperm membranes and DNA integrity impairment of sperm function Muiño-Blanco et al, 2008). It is well known that ram spermatozoa are more sensitive to coldshock stress than those of other species (Muiño-Blanco et al, 2008). In fact, the ram exhibits a faster DNA degradation under similar conditions than other species studied (Gosálvez et al, 2007).…”

“…The role of seminal plasma (SP) in mammalian sperm function remains largely a matter of speculation as both inhibitory and stimulating effects have been found (Muiño-Blanco et al, 2008). It has been reported that exposure of ram spermatozoa to seminal plasma causes a reduction of fertility (Dott et al, 1979), although some components of the seminal plasma, such as certain proteins, seem to have the important function of maintaining the stability of the membrane up to the process of capacitation, and are able to protect and repair the coldshock damage to sperm (Muiño-Blanco et al, 2008).…”

“…It has been reported that exposure of ram spermatozoa to seminal plasma causes a reduction of fertility (Dott et al, 1979), although some components of the seminal plasma, such as certain proteins, seem to have the important function of maintaining the stability of the membrane up to the process of capacitation, and are able to protect and repair the coldshock damage to sperm (Muiño-Blanco et al, 2008). However, in practice, semen dilution in the ram has to be done as soon as possible after recovery to avoid the inhibitory effects of seminal plasma.…”