Aim: This study was designed to explore factors which influence binding of dead versus live sperm to glass filters.Methods: Multiple semen collections from bulls were used to explore selective filtration of bull sperm as influenced by nonlethal inhibition of sperm motility with fluoride, killing of sperm by quick-freezing, alteration of the glass surface with silicone, and different intervals of sexual rest between semen collections. Results: A comparison of glass spheres 100, 200 and 390 μm in diameter indicated that 200μm spheres were optimal for selective filtration. Quantitative separation of live from dead sperm was demonstrated with a correlation between the percentage of motile sperm and retention of sperm by the filter of r =-0.87 (P < 0.05). Up to 0.02 mol/L NaFl did not alter the proportion of sperm retained by the filter despite inhibiting sperm motility during filtration, an inhibition which was reversible. Proportions of live-dead sperm, based upon eosin staining, were unaffected by fluoride. Coating the glass spheres with silicone greatly reduced selective filtration. Dead sperm adherence to glass wasreduced and resistance to NaFl inhibition was increased by daily ejaculation versus one-week intervals of sexual rest. Conclusion: These studies indicate that the adherence of sperm to glass is primarily due to some form of physico-chemical change accompanying death of the sperm cell independent of active sperm motility. This attraction between the sperm plasma membrane and glass is modified by the age of the ejaculated sperm. This information is useful in evaluating different clinical procedures used for sperm separation.

AIMThe study was designed to examine the effects of cryoprotective media, and glycerolating and thawing procedures on human sperm motility and gel penetrating ability.

METHODFifteen unselected donors provided semen varying in quality that was distributed in a factorial design across three cryoprotectants (glycerol, egg yolk-citrate-glucose-glycerol and egg yolk-tris-glucose-glycerol). Also, glycerol was added at room temperature versus at 4 degrees C. Two thaw temperatures were tested (laboratory air temperature for 10 min versus a 65 degrees C waterbath for 4 seconds). The proportion of total and progressively motile sperm was estimated immediately after thawing and following incubation at 35 degrees C for 2 h. Migration of sperm for 30 min at 37 degrees C through polyacrylamide gel was tested.

RESULTSDonors differed greatly, with post-thaw total motility of sperm ranging from 9 to 44% (P<0.05). Egg yolk-citrate-glucose-glycerol and egg yolk-tris-glucose-glycerol were superior to glycerol alone (post-thaw values of 35, 37 and 21%, respectively, P<0.05). This was due primarily to poor sperm survival when semen was cooled to 4 degrees C without glycerol or egg yolk. The two thaw temperatures gave similar results. Sperm migration tests paralleled the motility results, but were more sensitive in detecting differences.

CONCLUSIONEgg yolk, particularly in a tris-based medium that is widely used in domestic animals, improved the cryopreservation of both good and poor quality human semen.

Cryopreservation ; methods ; Cryoprotective Agents ; pharmacology ; Ejaculation ; Glycerol ; pharmacology ; Humans ; Male ; Organ Preservation Solutions ; Semen Preservation ; methods ; Sperm Motility ; drug effects ; physiology ; Spermatozoa ; drug effects ; physiology ; Tissue Donors