Caspase 3 activation in human spermatozoa in response to hydrogen peroxide and progesterone.
OBJECTIVE
To determine the role of calcium signaling on apoptosis evoked by the reactive oxygen species H2O2 and by the physiological agonist P in human ejaculated spermatozoa.


METHODS
Laboratory study.


METHODS
Center for assisted human reproduction in a hospital in Spain.


METHODS
Forty-five healthy volunteers.


METHODS
Spermatozoa were treated with increasing concentrations of hydrogen peroxide (H2O2; 10 microM, 100 microM, and 1 mM) or with 20 microM of P for 5-120 minutes.


METHODS
Activation of caspase-3 and -9 as well as phosphatidylserine externalization were examined in human ejaculated spermatozoa by fluorescence methods.


RESULTS
Hydrogen peroxide and P induced activation of caspase-3 and -9. In addition, the effect of H2O2 and P was time dependent. Dimethyl-1,2-bis (aminophenoxy) ethane-N,N,N',N'-tetraacetic acid loading was able to inhibit H2O2- and P-induced caspase-3 activation and phosphatidylserine externalization. Pretreatment of spermatozoa with Ru360, to block the calcium uptake into mitochondria, also was able to decrease the activation of caspase-3 and phosphatidylserine exposure that was stimulated by either H2O2 or P.


CONCLUSIONS
These findings suggest that H2O2- and P-induced mitochondrial apoptosis is dependent on calcium signaling.
D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D053148:Caspase 3 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008297:Male; D011374:Progesterone / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology / Q000201:enzymology*
D011374:Progesterone; D006861:Hydrogen Peroxide; D053148:Caspase 3; D053453:Caspase 9; D002118:Calcium