Analysis of endometrial myeloid and lymphoid dendritic cells during mouse estrous cycle

This study was performed to evaluate the frequency and localization of endometrial myeloid (CD11c(+) CD11b(+)) and lymphoid (CD11c(+) CD8alpha(+)) dendritic cells (DCs) at different stages of murine estrous cycle. To address the systemic effect of ovarian hormones fluctuations during estrous cycle, the same variables were studied in splenic DCs as well. Stages of the estrous cycle of Balb/c mice were determined by examination of vaginal smears. Frozen sections of uterus and spleen at each stage of estrous cycle were stained for CD11c and MHC-II. Two-color immunohistochemistry was also carried out using anti-CD11c with one of the antibodies against CD11b, CD8alpha, CD86, and DEC-205. The average density of DCs and relative percentage of myeloid and lymphoid DCs (MDCs and LDCs) were determined at each stage of estrous cycle by morphometric analysis. Our results showed that DCs were present throughout the estrous cycle in mice endometrium, but their frequency was highest at estrus and lowest at proestrus (P<0.005). The lymphoid subset of DCs was more prominent at estrus relative to those at other stages (P<0.005). Conversely, the relative percentage of myeloid DCs at estrus was significantly lower compared to other stages (P<0.005). Nearly all endometrial and splenic DCs expressed CD86 and MHC-II. At proestrus, and particularly at estrus, DCs were more concentrated subadjacent to the luminal and glandular epithelial layers with some scattered throughout the stroma whereas, at metestrus and diestrus, DCs were randomly distributed in stroma and around the glandular and luminal epithelial layers. The number and immunophenotype of splenic DCs were not statistically different between stages of estrous cycle. Our results suggest that endometrial but not splenic myeloid and lymphoid DCs are influenced by steroid hormones during estrous cycle.