Modulation of sperm tail protein tyrosine phosphorylation by pentoxifylline and its correlation with hyperactivated motility.
OBJECTIVE
To assess the effect of pentoxifylline on human sperm functions that are crucial to fertilization.


METHODS
Prospective, controlled study.


METHODS
Academic tertiary care institute.


METHODS
Healthy male sperm donors.


METHODS
The effects of pentoxifylline (3.6 mM) on hyperactivated motility, sperm binding to the zona pellucida, and sperm protein tyrosine phosphorylation were evaluated.


METHODS
Hyperactivated motility was assessed by computer-assisted motion analysis, and tight binding of sperm to homologous zonae pellucidae was examined using the hemizona assay. Sperm protein phosphorylation was evaluated using indirect immunofluorescence with an antibody to phosphotyrosine (PY20).


RESULTS
Pentoxifylline significantly stimulated hyperactivated motility at 1 hour and 4 hours; it also significantly increased sperm binding to the zona pellucida and enhanced sperm tail tyrosine phosphorylation at 4 hours under capacitating conditions. There was a statistically significant correlation between hyperactivated motility and sperm tail protein phosphorylation.


CONCLUSIONS
Pentoxifylline stimulates sperm functions that are essential to achieving fertilization under in vitro conditions in sperm obtained from fertile men. The enhancement of hyperactivated motility is associated with the stimulation of sperm tail tyrosine phosphorylation, suggesting a causal relation and the involvement of a modulatory effect after cyclic adenosine monophosphate-dependent phosphorylation of intermediate proteins.
Nassar
A
A
The Jones Institute for Reproductive Medicine, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk 23507, USA.
Mahony
M
M
Morshedi
M
M
Lin
M H
MH
Srisombut
C
C
Oehninger
S
S
D005307:Fertilization in Vitro; D006801:Humans; D008297:Male; D010431:Pentoxifylline / Q000494:pharmacology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D011446:Prospective Studies; D012016:Reference Values; D013081:Sperm Motility / Q000187:drug effects*; D013082:Sperm Tail / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*; D015044:Zona Pellucida
D010726:Phosphodiesterase Inhibitors; D014443:Tyrosine; D010431:Pentoxifylline