Matrix metalloproteinases (MMP-2 and MMP-9) and tissue inhibitor-2 of matrix metalloproteinases (TIMP-2) in the placenta and interplacental uterine wall in normal cows and in cattle with retention of fetal membranes
I. Walter et A. Boos, Matrix metalloproteinases (MMP-2 and MMP-9) and tissue inhibitor-2 of matrix metalloproteinases (TIMP-2) in the placenta and interplacental uterine wall in normal cows and in cattle with retention of fetal membranes, PLACENTA, 22(5), 2001, pp. 473-483
Matrixmetalloproteinases (MMPs) and tissue inhibitors of matrix metalloprot
einases (TIMPs) play a key role in tissue re-modelling in the placenta. In
the present study, distribution of MMP-2, MMP-9 and TIMP-2 was demonstrated
immunohistochemically in the bovine placenta and interplacentomal tissue.
Specimens representing the whole gestation until parturition were processed
. Additionally, materials from cows with and without retention of fetal mem
branes were compared. MMP-2 expression was abundant in the maternal septae
of the placentome in early gestation, with ongoing pregnancy immunoreactivi
ty was restricted to the stromal tissue at the openings of maternal crypts.
The chorionic epithelium opposite to these regions was also positive for M
MP-2. MMP-9 expression was observed in the chorionic epithelium, except in
the giant binucleate cells. In addition, the maternal epithelium and stroma
showed immunoreactivity for MMP-9. No differences in MMP-2 and MMP-9 distr
ibution could be observed between cows with proper release of fetal membran
es and cows with retained fetal membranes. Giant binucleate cells expressed
TIMP-2 during the whole gestation. Immunostaining for alpha -smooth muscle
actin revealed contractile elements in the bovine placentome. Balance betw
een proteolytic enzymes and their activators and inhibitors is essential fo
r regular development of the placenta. The expression of TIMP-2 in the gian
t binucleate cells indicates an essential role of inhibitory factors during
gestation. It is likely that less TIMP-2 is produced at the end of pregnan
cy as the number of binucleate cells is diminished. (C) 2001 Harcourt Publi
shers Ltd.