In the endometrium preparing for pregnancy, the stromal matrix components of the cells and their products begin structural differentiation due to endometrial receptivity. According to the hypothesis that 'extracellular matrix (ECM) proteins and adhesion molecules take roles in the structural differentiation as a result of endometrial decidualization', our aim was to determine the roles of ECM molecules laminin, fibronectin and adhesion proteins integrin a5 and b4 in the decidulization and implantation by examining the emergence and changing distribution of these proteins. In this study, five experimental groups, consisting of 40 pregnant animals on pregnancy days 4-8, were used. Paraffin tissue serial sections that were 6-8 µm in thickness from the implantation areas were stained by immunohistochemical techniques. Decidual reaction area (DRA) was first observed on pregnancy day 4. Fibronectin was observed densely in the center of the DRA on pregnancy days 4, 5 and in the primary decidual area (PDRA) on pregnancy days 6-8. Although integrin a5 had a similar staining to fibronectin up to pregnancy day 6, it was very weak in PDRA after that day. While laminin was dense in the basal lamina of the lumen and glandular epithelium and in the periphery of the DRA at the beginning, it was observed to be dense in the secondary decidual area (SDRA) after pregnancy day 6 and to have paralel immunoreactivity to integrin b4 on all pregnancy days. In conclusion, we can say that decidual reaction appears on pregnancy days 4-8 and not only laminin and fibronectin but also integrin a5 and b4 take part actively in decidual tissue formation and implantation events in the endometrium of rat uterus.

In the endometrium preparing for pregnancy, the stromal matrix components of the cells and their products begin structural differentiation due to endometrial receptivity. According to the hypothesis that 'extracellular matrix (ECM) proteins and adhesion molecules take roles in the structural differentiation as a result of endometrial decidualization', our aim was to determine the roles of ECM molecules laminin, fibronectin and adhesion proteins integrin a5 and b4 in the decidulization and implantation by examining the emergence and changing distribution of these proteins. In this study, five experimental groups, consisting of 40 pregnant animals on pregnancy days 4-8, were used. Paraffin tissue serial sections that were 6-8 µm in thickness from the implantation areas were stained by immunohistochemical techniques. Decidual reaction area (DRA) was first observed on pregnancy day 4. Fibronectin was observed densely in the center of the DRA on pregnancy days 4, 5 and in the primary decidual area (PDRA) on pregnancy days 6-8. Although integrin a5 had a similar staining to fibronectin up to pregnancy day 6, it was very weak in PDRA after that day. While laminin was dense in the basal lamina of the lumen and glandular epithelium and in the periphery of the DRA at the beginning, it was observed to be dense in the secondary decidual area (SDRA) after pregnancy day 6 and to have paralel immunoreactivity to integrin b4 on all pregnancy days. In conclusion, we can say that decidual reaction appears on pregnancy days 4-8 and not only laminin and fibronectin but also integrin a5 and b4 take part actively in decidual tissue formation and implantation events in the endometrium of rat uterus.