Submitted December 14, 2004
Returned for revision January 16, 2005
Accepted March 15, 2005
Pregnancy
Role of Neutrophils in Matrix Metalloproteinase Activity
in the Preimplantation Mouse Uterus
Etsuko Daimon
and
Yoshinao Wada *
* To whom correspondence should be addressed. E-mail: waday{at}mch.pref.osaka.jp.
Abstract
Matrix metalloproteinases (MMPs) have been implicated in
embryonal implantation
processes such as trophoblast invasion and
decidualization. The temporal and spatial
distributions of MMP bioactivities were analyzed by in
situ zymography, which indicated
these activities to be markedly increased in the
post-coital mouse uterus as compared with
the later implantation stage. Activity was ascribed to
proMMP9, which moved from the
uterine serosa to the endometrium but was not associated
with mRNA upregulation. The
activity was co-localized with infiltrating neutrophils,
and neutropenic mice did not exhibit
MMP9 expression. Removing the seminal vesicles from male
mice abolished the
post-coital increase in MMP9 in the female. These results
indicate the major MMP
activity in the preimplantation uterus to originate in
proMMP9-bearing neutrophils
attracted by seminal plasma. Considering our results
together with those of previous
reports of reduced fertility in Mmp9-deficient
female mice, we speculate that neutrophil
infiltration participates in the extracellular matrix
degradation needed to support pregnancy.
Key words:
Pregnancy •
Fertilization •
Implantation •
Seminal vesicles •
Uterus
