| dc.description.abstract |
The metabolism, rate of intracellularaccumulation of sugars, motility and ultrastructure of ejaculated tammar spermwere impaired by swim-up into artificial media, particularly when the cellswere subsequently exposed to N-acetyl-D-glucosamine (NAG). The inclusion ofhyaluronate, serum albumin, catalase or Desferal in swim-up media helpedprevent deterioration of sperm motility, but failed to prevent detrimentalNAG-induced metabolic and ultrastructural changes. However, the sperm wereunavoidably diluted during swim-up into artificial media and their behaviouralproperties were modified by dilution. Thus, sperm collected from the caudaepididymidis were immotile and their rate of oxygen uptake was low inundiluted caudal epididymal semen (CES). Nevertheless, these sperm wereviable, and vigorous motility was induced by 5- to 50-fold dilution inKrebs-Ringer phosphate (KRP). Sperm respiration also dramatically increasedwith moderate dilution (5- or 15-fold) in KRP, but decreased again at higherrates (50-fold). This suggested that motility and the metabolic properties oftammar sperm are modified both by dilution and on leaving the suppressingconditions of the epididymis. Diluted tammar epididymal sperm also displayed aPasteur effect, but rapidly lost capacity for motility in an oxygen-depletedatmosphere. It was concluded hat swim-up procedures compromise ejaculatedtammar sperm by promoting dilution-induced changes. This may alter thepermeability of the membrane with loss of the enzymes that process the ammoniagenerated during the metabolism of NAG in seminal plasma. Subsequent exposureto NAG further promotes ultrastructural damage culminating in loss ofviability. |
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