Observations by scanning electron microscopy of oviductal epithelial cells from cows at follicular and luteal phases

Abstract

The luminal surfaces of epithelial cells in various regions of the bovine oviduct from cows, at the follicular and luteal phases of the estrous cycle, were examined by scanning electron microscopy. Marked cyclic changes were observed on the surface of the epithelium in the fimbriae and ampulla, but few changes were found in the isthmus and uterotubal junction. The epithelium of the fimbriae and ampulla of oviducts in the follicular phase were densely ciliated, and the cilia concealed the apical processes of the nonciliated cells. In the luteal phase, the nonciliated cells predominated in the epithelium and most of the ciliated cells were hidden by the bulbous processes of the nonciliated cells. The epithelium of the ampullar-isthmic junction showed similar changes, but to a lesser extent. In the isthmus and at the utero-tubal junction, the apical surfaces of the nonciliated cells were flat or gently rounded during the estrous cycle. Quantitative examinations by light microscopy showed that the mean percentage of ciliated cells significantly decreased in the fimbriae and ampulla at the luteal phase, but not in the other regions. The height of ciliated cells decreased dramatically in the fimbriae, ampulla, and ampullar-isthmic junction at the luteal phase. By contrast, the height of nonciliated cells decreased significantly in the ampullar-isthmic junction, isthmus, and utero-tubal junction at the luteal phase, but not in the fimbriae and ampullae. The results demonstrate that there are regional variations and cellular differences in the cyclic changes associated with the oviductal epithelial cells in the cow.

Amino acids metabolism and degradation is regulated during porcine oviductal epithelial cells (OECs) primary culture in vitro – a signaling pathways activation approach

“…During follicular growth, in the vesicular phase, OEC cells rapidly proliferate, increase epithelial thickness, and the number of ciliates cells and secretory cells. On the other hand, during the luteal phase, the number of epithelial cells decreases together with OECs secretory activity [21], [22].…”

“…Symbols and names of the selected genes are also shown 24 ing embryo. These studies are therefore useful in the analysis of fertility problems and provide many information on how to improve the quality of developing embryos in vitro [22], [26]. Substances secreted by the OECs influence the sperm, improving their ability to fertilise oocytes [20].…”

Does migrative and proliferative capability of epithelial cells reflect cellular developmental competence?

“…Ciliated cells are found to be abundant during the follicular phase, with their proportion dropping drastically during luteal phase [45]. This is explainable, as the ciliated cells, have been proven to be necessary in proper transport of the cumulus-oocyte complex to the ampulla during ovulation, to make the fertilization possible [46].…”

The differentiation and transdifferentiation of epithelial cells in vitro – is it a new strategy in regenerative biomedicine?

“…Two types of cells are primarily present, ciliated cells that facilitate the flow of oviductal fluid to allow the progression of oocyte and/ or fertilized zygote, and secretory cells, responsible for secretion of contents specific to said fluid [36]. The amount of ciliated cells varies highly, peaking just before and during ovulation and reaching levels close to zero during the luteal period [37]. The overall proportion of the two types of oviductal epithelial cells is regulated, by both proliferation and differentiation of secretory cells.…”