L. Roblero et al., EFFECT OF COPPER-ION ON THE MOTILITY, VIABILITY, ACROSOME REACTION AND FERTILIZING-CAPACITY OF HUMAN SPERMATOZOA IN-VITRO, Reproduction, fertility and development, 8(5), 1996, pp. 871-874
The objective of this study is to provide additional information on th
e effect of copper ion (Cu2+) in preventing pregnancy. Human spermatoz
oa, selected by the swim-up method, were incubated for 0, 5 or 24 h in
the presence of 10 ng, 1 mu g, 10 mu g or 100 mu g of Cu2+ mL(-1) in
BWW culture medium, and then evaluated in terms of their motility, via
bility, acrosome reaction (AR) and the capacity to penetrate zona-free
hamster eggs. AR and penetration in zona-free hamster eggs were asses
sed at 5 h of incubation. Motility, viability and AR in sperm incubate
d for 5 h were significantly affected by Cu2+ at a concentration of 10
0 mu g mL(-1) but not at the lower concentrations. Incubation for 24 h
did not affect motility and viability of sperm incubated in the prese
nce of concentations of Cu2+ ranging from 10 ng mL(-1) to 10 mu g mL(-
1), but a concentration of 100 mu g mL(-1) caused a significant decrea
se in both parameters. In contrast, the penetration rate of zona-free
hamster oocytes significantly decreased compared with that of controls
, when only sperm were incubated in the presence of concentrations of
Cu2+ ranging from 10 ng mL(-1) to 10 mu g mL(-1), and no penetration w
as observed in the presence of 100 mu g mL(-1) of Cu2+ When only oocyt
es were exposed to Cu2+, th, penetration rate dropped to 50% of that o
f the controls. Finally, when both gametes were exposed to Cu2+ before
co-incubation, the penetration rate fell to zero for every concentrat
ion tested. Results showed that copper, at concentrations similar to t
hose released from intrauterine devices (IUD), affects the fertilizing
capacity of human gametes in vitro and interferes with the sperm-oocy
te interaction leading to fertilization. These effects suggest that th
e principle action of Cu2+ released from Cu-IUD is to act as a preconc
eption contraceptive agent when delivered in endometrial and oviducal
fluids.