Determination of tight and gap junction proteins distribution by immunohistochemical methods in the rat uterus epithelium during the estrous cycle

Continuity and semi-permeability of epithelial tissue occurs via side to side connections between epithelial cells. Tight junctions play a major role in interepithelial connection, gap junctions provide reciprocal communication between cells without material passage through the paracellular pathway.During a menstrual period ovarian hormones lead to changes in tight junctions dimensions as well as gap junctions numbers and dimensions.In our study we investigated tight junction proteins claudin 5 and 7, ZO-1, JAM?1 distribution, and gap junction protein connexin 43 distribution by immunohistochemical methods in order to determine changes in the junctional unit variations in the rat uterus during the estrous cycle.ZO-1, claudin 5, JAM-1 were observed in apical cell membrane, side to side apical spaces of both superficial and glandular epithelial in diestrus, proestrus, estrus phases. Furthermore cytoplasmic reaction was observed in superficial epithelial cells. Connexin 43 shows immunoreaction in basal cell membrane, side to side basolateral spaces between cells predominantly in superficial epithelial and exhibited a strong staining in apical cytoplasm and membrane on metaestrus phase, although this phase showed the weakest reactivity for other antibodies.In conclusion, all of the antibodies besides connexin 43 showed weak reactivity in metaestrus phase, therefore connexin 43 is supposed to form an implantation window for a possible pregnancy in metaestrus phase as well as it plays a role in intercellular communication for implantation.