The Effect of Cold Shock and Freeze-Thawing on Release of Phospholipids by Ram, Bull, and Boar Spermatozoa

Abstract

The effects of cold shock and freeze-thawing on the release of total phospholipid phosphorus and of specific phospholipids from ram, bull, and boar spermatozoa are examined. Species differences are apparent, both in the absolute amount of total phospholipids released and in the conditions required to effect a loss of individual phospholipids. The phosphoglycerides most affected by the temperature treatment are choline plasmalogen, phosphatidyl choline, and phosphat idyl ethanolamine. The loss of phospholipids is most specific in boar spermatozoa. Bull spermatozoa suffer a greater overall and more general breakdown of phospholipids, indicating disruption of the cell structure. This is in contrast to the more specific phospholipid losses from ram and boar spermatozoa, which may indicate a more localized region of damage and release of material, possibly acrosomal. The loss of phospholipid may be correlated with the species differences in the fertility of the frozen spermatozoa.

Effect of cholesterol-loaded-cyclodextrin on sperm viability and acrosome reaction in boar semen cryopreservation

“…Membrane destabilization occurs when the membrane undergoes the phase transition, from the fluid phase to the gel phase, as temperature is decreased. During this phase transition, phospholipids are lost from the plasma membrane leading to increased membrane permeability, membrane disruption, and cell death (Darin-Bennett et al, 1973;Watson, 1981). If the temperature at which the membrane lipid phase transition occurs could be lowered, or if the membrane phase transition could be eliminated completely, membranes would remain fluid at low temperatures and the damage that occur to membranes may be reduced.…”

Metabolism of boar spermatozoa before, during preparation for, and after storage in liquid nitrogen

“…Healey, 1969;Kann & Hollande, 1972;Yasuda & Tanimura, 1974;Larsson & Einarsson, 1975). Such membrane damage is paralleled by loss of lipid during cold-shock or freezing-thawing (Hartree & Mann, 1959;Pickett & Komarek, 1967;Darin-Bennett et ai, 1973 (Darin-Bennett et al, 1973), and this may be related to the decreased relative incorporation of stearic acid into phosphatidyl choline and of both stearic and palmitic acids into phospholipids in general. Although not significant the apparent decline in incorporation of the fatty acids into the fraction containing phosphatidyl serine may be related to the protection by phosphatidyl serine of boar spermatozoa against cold shock (Butler & Roberts, 1975 (Watson, 1975).…”

“…That membrane damage occurs during storage has been inferred from the loss of intracellular constituents (Mann, 1964;Graham & Pace, 1967; Darin-Bennett, Poulos & White, 1973), from the increased membrane permeability to stains (Easley, Mayer & Bogart, 1942;Mann, 1964), and from morphological changes (e.g. Healey, 1969;Kann & Hollande, 1972;Yasuda & Tanimura, 1974;Larsson & Einarsson, 1975).…”

Physiological roles of relaxin in prefertilizing activities of spermatozoa

“…Other studies also observed lower cholesterol content after freezing-thawing of porcine (Cerolini et al, 2001) and buffalo (Kadirvel et al, 2009) spermatozoa. Sperm membranes are known to release phospholipids into surrounding medium during cold shock (Darin-Bennett et al, 1973). Release of cholesterol from the membrane plane, a probable consequence of peroxidative damage to membrane lipids, could lead to the premature capacitation of cryopreserved bovine spermatozoa (Cormier et al, 1997).…”