The effect of the motility stimulants, caffeine, pentoxifylline, and 2-deoxyadenosine on hyperactivation of cryopreserved human sperm.
OBJECTIVE
To determine if the motility stimulants, caffeine (7 mM), pentoxifylline (3 mM), 2-deoxyadenosine (3 mM), and a combination of the three would induce hyperactivated (HA) motility.


METHODS
Controlled laboratory study of stimulants using cryopreserved semen from 10 donors at three time points.


METHODS
The study was performed in the Andrology Laboratory at Prince Henry's Institute of Medical Research Clayton, Victoria, Australia.


METHODS
Stimulants in doses maximally effective for stimulation of motility were incubated with suspensions of previously cryopreserved sperm.


METHODS
Motility characteristics (curvilinear velocity [VCL], linearity [LIN], and maximum amplitude of lateral head displacement [ALHmax]) were derived using the single cell track facility of the CellSoft computer-automated semen analyzer (Cryo Resources Ltd., Montgomery, NY). Videotapes were visually inspected, and 125 sperm cell trajectories exhibiting characteristic HA behavior were identified. The HA motility thresholds (5th or 95th centiles) were as follows: VCL > 74 microns/s, LIN < 74%, and ALHmax > 4.7 microns. Cells with motility characteristics outside these limits were regarded as HA. The significance of the effect of the stimulants on the proportion of sperm exhibiting HA was examined by Poisson regression analysis.


RESULTS
Sperm washing (removal of the cells from the cryoprotectant) and swim-up caused significant changes in the VCL and straight line velocity and a twofold (5.6% to 11.9%) increase in the proportion of HA cells. In the presence of motility stimulants, the proportion of HA cells was significantly increased threefold (11.9% to 32.5%) above that seen in the control washed sperm. Hyperactivated motility declined after 1 to 2 hours, but 2-deoxyadenosine demonstrated a prolonged effect.


CONCLUSIONS
These motility stimulants that affect adenosine 3':5' monophosphate in human sperm stimulate cyclic hyperactivation.
Mbizvo
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MT
Prince Henry's Institute of Medical Research, Monash Medical Centre, Clayton, Victoria, Australia.
Johnston
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RC
Baker
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GH
D002110:Caffeine / Q000494:pharmacology*; D003201:Computers; D015925:Cryopreservation; D003839:Deoxyadenosines / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010431:Pentoxifylline / Q000494:pharmacology*; D012662:Semen Preservation; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*
D003839:Deoxyadenosines; D002110:Caffeine; D010431:Pentoxifylline