557
CHANGES IN MORPHOLOGY OF MOUSE OVIDUCT AMPULLA DURING EARLY PREGNANCY.
Morita, Maki1, Sugimoto, Miki1, Manabe, Noboru1, Miyamoto, Hajime1, 1
ABSTRACT- The mammalian oviduct provides an optimal environment for maturation and union of gametes and for early embryonic development. This environment is nutritive and protective for sperms, oocytes and embryos. In mice, embryos are reported to stay in the oviduct ampulla until Day 2.5 of gestation and pass through the isthmus on Day 3.5, and are implanted on Day 4.5 in the uterus. In this study, we examined cell proliferation and the morphology in the oviduct ampulla of early-pregnant mice. ICR mice on Day 0.5, 1.5, 2.5 and 3.5 of gestation were administered 5 bromo-2'-deoxyuridine (BrdU) 6 hours before euthanized. Oviduct Ampullae were removed and were fixed in 10% formalin or in 2.5% glutaraldehyde and 1% osmium tetraoxide, and embedded in paraffin or in epoxy resin, respectively. Semi-thin sections from resin-embedded tissue were stained with Giemsa and basic fuchsine. On these sections, epithelial cells were classified into non-ciliated cells or ciliated cells. Non-ciliated cells were further divided according to the stainability to basic fuchsine. BrdU labeling was detected immunohistochemically on the paraffin sections. Ciliated cells were the major cell type in the epithelial cells facing to the lumen. On Day 0.5, non-ciliated cells were slightly protruded into the lumen. On Day 3.5, the population of the non-ciliated cells increased and the protrusions grew beyond cilia of ciliated cells. Basic fuchsine stained the tips of non-ciliated cells and the percentage of stained cells reached a maximum on Day 3.5. This indicated mucus material accumulated in the cytoplasm of non-ciliated cells. Mitosis was seen on resin sections and S-phase cells were more frequently observed on Day 1.5 than on other days. The present results indicate that epithelial cells of oviduct ampulla proliferate after fertilization and the secretory activity subsequently became higher to support an optimal environment for preimplantation embryogenesis.
KEY WORDS: mouse, oviduct, pregnancy