E. Delamirande et C. Gagnon, CAPACITATION-ASSOCIATED PRODUCTION OF SUPEROXIDE ANION BY HUMAN SPERMATOZOA, Free radical biology & medicine, 18(3), 1995, pp. 487-495
Previous results demonstrating the role of the superoxide anion in hum
an sperm capacitation indirectly suggest that the superoxide anion is
not only essential to this process, but is also generated by spermatoz
oa themselves. Our aim was to provide direct evidence for production o
f superoxide anion by capacitating spermatozoa. Three chemiluminescenc
e probes were tested to detect the superoxide anion. Luminol- and luci
genin-amplified chemiluminescence of capacitating spermatozoa did not
differ from that of background level. However, significant SOD-inhibit
able chemiluminescence was observed when the Cypridina luciferin analo
g, MCLA, was used as probe. The chemiluminescence associated to capaci
tation of spermatozoa incubated in Ham's F-10 supplemented with fetal
cord serum ultrafiltrate was 1270 +/- 77 mV/10 s (with 8 X 10(6) cells
/ml; n = 37), and corresponded to levels of sperm hyperactivation (12
+/- 1%) and capacitation (17 +/- 2%) that were significantly different
from those of control spermatozoa (4.9 +/- 0.8% and 6 +/- 1%, respect
ively). MCLA was cell impermeant and superoxide specific. The level of
capacitation-associated chemiluminescence was directly related to spe
rm concentration up to 30 X 10(6) cells/ml. Sperm production of supero
xide anion started at the beginning of incubation in capacitating cond
itions and was sustained over more than 4 h. This is the first direct
evidence for the generation, by human spermatozoa, of a sustained leve
l of superoxide anion that is associated with the progressive developm
ent of hyperactivation and capacitation.