Glycodelin, also known as placental protein 14, has been implicated in
endometriosis-related infertility. To determine the role of glycodelin and its
glycosylated state, the influence of recombinant nonglycosylated-glycodelin
(nongly-glycodelin) and glycosylated-glycodelin
(gly-glycodelin) on human sperm function was evaluated.
Whereas there was a significant (P<0.001) increase in
the capacitation of nongly-glycodelin-treated
spermatozoa compared with untreated controls (28.8 1.0%
v. 21 1.5% respectively), treatment of
spermatozoa with gly-glycodelin markedly
(P<0.001) inhibited capacitation (10.7 0. 3%);
acrosome reaction (AR) remained unaltered in all treatments. In a zona-free
hamster egg penetration assay, the egg penetration index was higher
(P<0.001) with
nongly-glycodelin-treated spermatozoa (3.4 0.3) than
with gly-glycodelin-treated spermatozoa (0.4 0.1) and
untreated spermatozoa (1.6 0.2). A similar influence of glycodelin on
capacitation was observed with hamster spermatozoa. However, the AR rate was
higher (P<0. 01) in
nongly-glycodelin-treated spermatozoa (39.4
1.6%) than in either gly-glycodelin-treated
spermatozoa (19.3 2.0%) or untreated controls (30.0 1.2%).
Moreover, the in vitro fertilization rate was
significantly (P<0.01) higher with
nongly-glycodelin treated-spermatozoa compared with
untreated spermatozoa (77.5 2.3% v. 52.9
4.3%) and gly-glycodelin-treated spermatozoa
(38.3 6.5%; P<0. 05). These results indicate
that whereas nongly-glycodelin improves,
gly-glycodelin inhibits, capacitation and fertilization
potential of human and hamster spermatozoa, and that the glycosylation status
of glycodelin determines its influence on sperm
function.
The Role of Placental Protein 14 in the Pathogenesis of Endometriosis