Spatio-Temporal Expression of Matrix Metalloproteinases-2 and -9 in Porcine Endometrium During Implantation

Implantation is a complex process and involves various molecules to maintain endometrial function. The remodeling of endometrial matrices is a necessary process during implantation. Matrix-Metalloproteinases (MMPs) like gelatinases (MMP-2 and -9) are considered to play important roles in this process. Real-time PCR, western blot and immunostaining analysis were used to study MMP-2 and -9 expression between/at attachment sites of endometrium of Days 13, 18 and 24 pregnant sows. The results indicate that MMP-2 mRNA and protein expression is higher than that of MMP-9 during implantation so it was proposed that MMP-2 plays a more vital role in endometrium during implantation in sows. During implantation, MMP-2 protein expression at attachment sites was higher than between attachment sites and this effect was significant at days 18 (p<0.01) and 24 (p<0.01) of pregnancy. The immunostaining of MMP-2 and -9 was found in stroma and luminal epithelium and the immunostaining of MMP-2 in stroma at attachment sites was stronger than between attachment sites. These results suggest that MMP-2 and -9 may mediate ECM degradation and remodeling of endometrium at attachment sites is greater than between attachment sites. The immunostaining of MMP-2 and -9 in stroma indicate the endometrial stromal decidualization-like in sows.