Morphological study of changes in the baboon oviductal epithelium during the menstrual cycle

Oviductal epithelium of the baboon, Papio cynocephalus, was studied utilizing light, scanning, and transmission electron microscopy. Results of counts made of nonciliated, ciliated, and ciliogenic cells were analyzed statistically. The percentages of nonciliated cells of the fimbria and ampulla during the early proliferative and late secretory stages of the menstrual cycle were significantly greater than those during the mid-proliferative and late proliferative-early secretory stages, due to deciliation. This paper emphasizes previously unreported apical surface morphology as viewed by scanning and transmission electron microscopy. The microvillar pattern of the fimbrial secretory cells differs from that of the ampullar and isthmic cells in that the microvilli originate from thick apical protrusions and vary greatly in length and number as related to the cycle. A ridge demarcating the apical intercellular junction is composed of rows of microvilli during the early proliferative and late secretory stages. During the early proliferative and late secretory stages an increased degree of invagination of the basal and lateral plasma membranes occurs as the height and width of the cells decreases. The general numbers and distribution of the organelles of the various types of oviductal cells agree with that described for the ampulla and isthmus by Verhage et al. [(1990) Am. J. Anat., 187:81-90]; however, fimbrial epithelium was not included in that study. Other cyclic ultrastructural changes not examined previously include variation in the number of lipid droplets and their location, and in the number and relationships of glycogen particles to other structures.