RESUMO
The present study is designed to study the light and electron microscopic structure of the rat vaginal epithelium during pregnancy. Furthermore, lectin histochemistry is used to know the changes of the terminal sugar of the glycoconjugate in the vaginal epithelium during pregnancy. The 0 day of pregnacy is defined as the day of presence of sperm in a vaginal smear. At 0 day of pregnancy, most of cells are flat in morphology except basal cell. Lightly-stained superficial cells had few cell organelles, and all the other cells had many intermediate filament bundles, microvilli-like processes and desmosomes. During pregnancy, the thickness of the vaginal epithelium was increased. The morphology of the mucous cells are changed from a cuboidal shape to a columnar one. The intermediate filament bundles are decreased in the mucous cell after first week of pregnancy. Lectin histochemistry showed the presence of alpha-L-fucose, alpha-D-galactose, beta(1, 4)-N-acetylglucosamine, alpha-D-N-acetylgalactosamine and galactosyl-beta(1, 4)-N-acetylglucosamine in the mucous cells. The basal cells also contained the same terminal sugars except galactosyl-beta(1, 4)-N-acetylglucosamine. Approaching to the birthday, the thickening of the mucous layer of the vaginal epithelium suggests that the mucous containing several glycoconjugates may play an important role to make the appropriate environment in the vaginal lumen during pregnancy and parturition.