Distribution of macrophages in the human fallopian tubes: an immunohistochemical and electron microscopic study

The fallopian tubes are essential for the normal transport of gametes, fertilisation and early embryonic development and transport. Their locomotive force is mainly due to the contractility of the smooth muscle cells, as well as to the ciliary activity of the tubal epithelium. Steroid hormones such as oestradiol and progesterone mediate changes in tubal morphology, in particular the tubal epithelium. It is well known that macrophages participate in the immune system, but recent studies have shown that they also play other roles under physiological conditions. They are known to be a source of prostaglandins of the E series, which influence the contractility of the uterine tube. Lymphocytes in the tubal mucosa can be involved in the process of immune tolerance, which could enable sperms and blastocysts to be transported through the oviduct under normal conditions without the activation of local immune mechanisms. Most of the evidence for mucosal immune responses in the female reproductive tract is related to the vagina, with less information available for the uterus. The less known segment in this regard is the oviduct, which prompted us to review and summarise the current state of knowledge of the immune system at the level of the human oviduct. The present study was therefore undertaken to examine the distribution and morphological properties of macrophages in the endosalpingeal stroma and smooth muscle layer of the human fallopian tubes. Thirty fresh fallopian tubes were examined, taken at the proliferative (7 cases) and secretory (12 cases) phases of the menstrual cycle, and during the postmenopausal period (11 cases). Sections were stained by immunocytochemistry with a primary antibody (CD 68) and were used for counting the macrophages. Ultrathin sections were stained with lead citrate and uranyl acetate and studied by means of electron microscopy to asses the ultrastructure of the macrophages. A significant difference was observed between reproductive and postmenopausal women in the number of macrophages (p<0.05). This study may help to clarify the possible role of macrophages of the uterine tubes in some cases of infertility in females.