Effect of incubating human sperm at room temperature on capacitation-related events.
OBJECTIVE
To determine the effect of human sperm incubation at room temperature (20 degrees C) upon capacitation-related events.


METHODS
Prospective study.


METHODS
Basic research laboratory.


METHODS
Semen samples were obtained from normozoospermic volunteers. Human follicular fluid (hFF) was collected from women undergoing assisted reproductive treatment.


METHODS
Spermatozoa were incubated for up to 18 hours at 20 degrees C and/or 37 degrees C.


METHODS
Protein tyrosine phosphorylation patterns, development of hyperactivated motility, and induction of acrosome reaction (AR) in response to hFF.


RESULTS
Spermatozoa incubated for 18 hours at 20 degrees C showed an array of tyrosine phosphorylated proteins similar to noncapacitated cells. After incubation at 20 degrees C, the percentage of spermatozoa displaying hyperactivated motility and undergoing acrosomal loss in response to hFF was significantly lower when compared with cells kept the same time at 37 degrees C. Conversely, spermatozoa incubated overnight at 37 degrees C could respond to hFF, either at 37 degrees C or 20 degrees C. When preincubation at 20 degrees C was followed by sperm exposure to 37 degrees C, capacitation-related events could be activated. In capacitated cells (16 hours at 37 degrees C), 2-hour incubation at 20 degrees C led to a significant decrease in acrosome reaction inducibility, suggesting sperm decapacitation.


CONCLUSIONS
Human sperm incubation at room temperature does not allow capacitation, although it does not affect hFF-induced acrosome reaction in capacitated cells. The blocking effect is overcome when spermatozoa are exposed to 37 degrees C.
Marín-Briggiler
Clara I
CI
Instituto de Biología y Medicina Experimental, CONICET-UBA, Vuelta de Obligado 2490, (1428) Buenos Aires, Argentina.
Tezón
Jorge G
JG
Miranda
Patricia V
PV
Vazquez-Levin
Mónica H
MH
D020101:Acrosome Reaction / Q000502:physiology; D001696:Biomechanical Phenomena; D015153:Blotting, Western; D003470:Culture Media; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D015571:Follicular Fluid / Q000502:physiology; D006801:Humans; D008297:Male; D010766:Phosphorylation; D011446:Prospective Studies; D011506:Proteins / Q000378:metabolism; D013075:Sperm Capacitation / Q000502:physiology*; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D014443:Tyrosine / Q000378:metabolism
D003470:Culture Media; D011506:Proteins; D014443:Tyrosine