αvβ3 Integrin Express on Mid-luteal Human Endometrium: An Immunogold and Immunofluorescent Staining Study

Introduction: The implantation is a complex procedure that involves many molecules. One of these molecules is integrin specially αvβ3 which serves as receptor for components of extra cellular matrix to act as bridging molecules between the blastocyst and the endometrial surface during the implantation process. By blocking αvβ3 interactions, the implantation can be impaired. Methods: The endometrial biopsies obtained from the anterior wall of the uterine cavity of 12 women. Each biopsy divided into three pieces; one fixed in 10% neutrally buffered formaldehyde for light microscopy and immunofluorescent study. The second fixed in 4% paraformaldehyde in 0.1 M phosphate buffer (pH 7.4) for immunogold electron microscopy and the third fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer (pH 7.4) for scanning electron microscopy. Afterwards, the biopsies evaluated by immunofluorescent, immunogold and scanning electron microscopy techniques. Results: Immunofluorescent staining demonstrated that αvβ3 integrin express only on luminal surface epithelium and glandular epithelium of mid-luteal phase. Immunogold staining images in mid-luteal phase samples showed that αvβ3 integrin express on ciliated, non- ciliated (pinopdes) cells and junctional complexes. While, no reactivity observed on the endometrial surface, using the negative control antibody or in specimens incubated without primary antibody in any of the specimens. Conclusion: The results showed that αvβ3 integrin express only on luminal surface epithelium and glandular epithelium in the mid-luteal phase of human endometrium and it may play a key role during the process of the embryo implantation. Targeting integrins may provide a new avenue for the development of contraceptive technologies, and the loss of this integrin in certain infertility states may signify the presence of implantation defects that reduce cycle fecundity in women.