Distribution Of Ciliated Cells Research Articles

Finely tuned ciliary alignment and coordinated beating generate continuous water flow across the external gills in Pleurodeles waltl larvae

Urodelan amphibian larvae develop three pairs of branching external gills on both sides of the pharyngeal region, and this study focuses on motile cilia on the gill surface. High-speed camera was used to observe ciliary strokes on the surface of the external gills of Pleurodeles waltl larvae. We found that the directionality of ciliary beating is position-dependent on the gill surface, and this rule is applicable to all the samples examined. For visualizing water flow around the external gills, we used bead suspensions. We revealed continuous anterior-to-posterior water flow generated by coordinated ciliary beating. Around the frontal surface of the gill stem (gill rachis), water flows countercurrent to the bloodstream beneath the gill epidermis. These results suggest that ciliary beating in each ciliated cell is coordinated, which cooperatively generates continuous and directional ciliary flow. We next visualized the overall distribution of ciliated cells on the gill surface by immunostaining of acetylated alpha-tubulin. Our results showed that the fine branches of external gills (fimbriae) have a circumferential distribution of cilia aligned orthogonal to the longitudinal axes of fimbriae, which facilitates water flow from proximal to the distal part of the fimbriae through the gills. This ciliary distribution pattern and directionality of cilia-driven flow are shared among five urodelan and two anuran species. Taken together, our findings suggest that the distribution and motility of ciliated cells on the surface of external gills is finely controlled, and this might support efficient respiration by the gills in urodeles.

TRPV4 is involved in levonorgestrel-induced reduction in oviduct ciliary beating.

Previous studies revealed the increasing risk of tubal pregnancy following failure of levonorgestrel (LNG)‐induced emergency contraception, which was attributed to the reduced ciliary motility in response to LNG. However, understanding of the mechanism of LNG‐induced reduction in the ciliary beat frequency (CBF) is limited. The transient receptor potential vanilloid (TRPV) 4 channel is located widely in the female reproductive tract and generates an influx of Ca2+ following its activation under normal physiological conditions, which regulates the CBF. The present study aimed to explore whether LNG reduced the CBF in the Fallopian tubes by modulating TRPV4 channels, leading to embryo retention in the Fallopian tubes and subsequent tubal pregnancy. The study provided evidence that the expression of TRPV4 was downregulated in the Fallopian tubes among patients with tubal pregnancy and negatively correlated with the serum level of progesterone. LNG downregulated the expression of TRPV4, limiting the calcium influx to reduce the CBF in mouse oviducts. Furthermore, the distribution of ciliated cells and the morphology of cilia did not change following the administration of LNG. LNG‐induced reduction in the CBF and embryo retention in the Fallopian tubes and in mouse oviducts were partially reversed by the progesterone receptor antagonist RU486 or the TRPV4 agonist 4α‐phorbol 12,13‐didecanoate (4α‐PDD). The results indicated that LNG could downregulate the expression of TRPV4 to reduce the CBF in both humans and mice, suggesting the possible mechanism of tubal pregnancy. © 2019 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Prenatal Bisphenol A Exposure Alters Epithelial Cell Composition in the Rhesus Macaque Fetal Oviduct.

Bisphenol A (BPA) is an endocrine disrupting compound that is a pervasive environmental contaminant. Although it has been reported to affect the development of a variety of fetal reproductive tissues, data on the effect of fetal BPA exposure on oviducts were extremely limited and were only available in mice. To determine if there are adverse effects of gestational BPA exposure on fetal oviduct, we exposed pregnant rhesus macaques with female fetuses to oral or nonoral BPA during the last trimester of gestation (day 100 to term). After the treatment, fetal oviducts were collected for morphology evaluation. BPA exposure altered the percentages of different cell types (ciliated, nonciliated, and secretory) in the fetal oviduct and resulted in a significant high ciliated cell population in the BPA-exposed fetal oviduct. The distribution of ciliated cells on the epithelium in the BPA-exposed fetal oviduct was also altered. Gestational BPA exposure reduced the expression of mucosubstance and uteroglobin in secretory cells in the fetal oviduct. A comparison of the outcome of the fetal oviduct studies with similar outcomes previously reported in the lung from the same fetuses demonstrates that BPA exhibits opposite effects in these two organs. In conclusion, the BPA-associated alterations in the fetal oviduct could potentially affect the oviduct morphology and function later in life with a negative impact on fertility. The mechanisms of action of the differential response in the oviduct and the lung to BPA exposure require further investigation.

The effects of intra-uterine kerosene infusion on endometrial epithelial cilia concentration

The endometrial muco-ciliary apparatus plays an important role in the clearance of fluid and inflammatory debris from the uterus. It has been documented that there is a significant difference in the distribution of ciliated cells between mares with normal fertility and mares with delayed uterine clearance. The infusion of kerosene into the uterus as a treatment for chronic infertility in mares has been described. Endoscopic, histologic and cytologic examination post infusion reveals severe acute inflammation that gradually resolves over seven to fourteen days. The goal of this study was to determine if the intra-uterine infusion of kerosene had an effect on the concentration of ciliated endometrial epithelial cells detectable via histologic examination of endometrial biopsies. Uterine biopsy samples were obtained from nine reproductively healthy mares the cycle prior to treatment. Four mares served as controls and were infused with saline, and five mares were treated with intra-uterine infusion of kerosene. Two hundred and fifty milliliters of saline or kerosene were infused into the uterus during estrus and uterine biopsy samples were acquired one, four, seven and twenty-one days after administration. The biopsy samples were fixed in Bouin’s solution and standard H&E sections were prepared. The percentage of ciliated endometrial epithelial cells was determined by counting a minimum of 100 endometrial cells and assessing the percentage that possessed tufts of tall cilia. There was no statistical difference between the

Early morphogenesis of ciliated cells in human oral cavity

Ciliated cells were found in the epithelium of the oral cavity of human embryos and fetuses starting from the seventh week of prenatal development. At the early stages of prenatal development (until the 13th week), cells with cilia cover most of the dorsal surface of the tongue and the soft palate, whereas they are found only near the gland ducts in the circumvallate and foliate lingual papillae after 17 weeks of development. The ultrastructure of the axoneme of cilia corresponds to the structure of motile cilia and is represented by nine microtubule doublets that surround the central pair of microtubule singlets. An immunohistochemical study performed on weeks 10-12 of development identified nerve endings associated with the ciliated cells. Until the 14th week of development, the cytoplasm of ciliated cells is immunopositive for NSE. The spatial distribution of ciliated cells in the tongue epithelium until the 13th week of development is not related to the morphogenesis of lingual papillae, and their role in the human oral cavity during the first trimester of pregnancy is unclear and requires further study.

Topographic and ultrastructural variations in isthmus segment of oviduct during oestrous cycle in Caprines

In the present study, the morphological variations in the isthmus segment of goat (Capra hircus) oviduct were studied using scanning and ultrastructural techniques during luteal and follicular phases of oestrous cycle. Topographic analysis of the isthmus epithelium in the follicular phase demonstrated irregular distribution of ciliated cells on the epithelium. A few secretory cells possessed bulbous apical processes which were concealed by the cilia. Cyclic changes were noticed in the secretory cells of isthmus. Under electron microscopy the isthmus region of the oviduct during the follicular phase revealed presence of almost blunt processes at their apical surfaces. The secretory cells were attached to the basal lamina and were characterized by the presence of secretory granules, numerous ribosomes, extensive smooth endoplasmic reticulum, well-developed golgi zones in the cytoplasm, and a microvillus luminal surface. The parallel use of these two methods in isthmus segment of the oviduct has enabled us to analyze the marked cyclic variations in the topography and fine structure during follicular and luteal phases of the oestrous cycle. The results of the present investigation on topography and ultrastructure will be of great help in explaining different bottlenecks of gamete interaction, maturation, fertilization, and early embryo development.

Regional cell shape changes control form and function of Kupffer's vesicle in the zebrafish embryo

Cilia-generated fluid flow in an ‘organ of asymmetry’ is critical for establishing the left–right body axis in several vertebrate embryos. However, the cell biology underlying how motile cilia produce coordinated flow and asymmetric signals is not well defined. In the zebrafish organ of asymmetry—called Kupffer's vesicle (KV)—ciliated cells are asymmetrically positioned along the anterior–posterior axis such that more cilia are placed in the anterior region. We previously demonstrated that Rho kinase 2b (Rock2b) is required for anteroposterior asymmetry and fluid flow in KV, but it remained unclear how the distribution of ciliated cells becomes asymmetric during KV development. Here, we identify a morphogenetic process we refer to as ‘KV remodeling’ that transforms initial symmetry in KV architecture into anteroposterior asymmetry. Live imaging of KV cells revealed region-specific cell shape changes that mediate tight packing of ciliated cells into the anterior pole. Mathematical modeling indicated that different interfacial tensions in anterior and posterior KV cells are involved in KV remodeling. Interfering with non-muscle myosin II (referred to as Myosin II) activity, which modulates cellular interfacial tensions and is regulated by Rock proteins, disrupted KV cell shape changes and the anteroposterior distribution of KV cilia. Similar defects were observed in Rock2b depleted embryos. Furthermore, inhibiting Myosin II at specific stages of KV development perturbed asymmetric flow and left–right asymmetry. These results indicate that regional cell shape changes control the development of anteroposterior asymmetry in KV, which is necessary to generate coordinated asymmetric fluid flow and left–right patterning of the embryo.

Morphological Features of the Luminal Surface of the Magnum in the Sexually Immature Ostrich (Struthio camelus)

Summary Observations were made, using scanning electron microscopy, of the surface features of the magnum in the immature ostrich during periods of ovarian inactivity, activity and regression. In birds with inactive ovaries the luminal surface of the magnum was lined with non-ciliated cells, which were densely covered by microvilli. In contrast, the magnum in birds with active ovaries was composed of ciliated and non-ciliated cells. The distribution of ciliated cells was not uniform, with clumps of cilia occurring next to non-ciliated areas. Samples collected from birds with regressing ovaries, during periods of decreasing daylength, revealed that the magnum was undergoing involution. The deciliation of ciliated cells and the presence of short microvilli on non-ciliated cells characterized magnal regression. These results suggest that ovarian activity and changes in daylength have a profound effect on the surface features of the magnum in the immature ostrich.

Morphological Study of Middle Ear and Eustachian Tube Part-one

Mucosa of the middle ear and the Eustachian tube were studied by the scanning electron microscope (SEM) in humans, dogs, rabbits and guinea pigs. The following results were obtained:1. Ciliated cells surrounded by nonciliated cells with microvilli were very few on the mucous of the middle ear. Distribution of ciliated cells was very various at the site of the tympanic bulla.2. Near the tympanic orifice of the Eustachian tube, less ciliated cells and numerous goblet cells were observed.3. The middle portion of the tube was found to be the most active. It was here that goblet cells and a large number of ciliated cells were found. Cilia were dense, uniform bent toward the pharyngeal end, and covered by a mucous blanket.4. Near the pharyngeal end, goblet cells were numerous, while cilia were scanty and not uniform in length.5. No significant difference could be seen among the four materials (humans, dogs, rabbits, guinea pigs).Our findings support the concept that middle ear clearance is carried out by an active mucociliary mechanism as in other parts of the upper respiratory system.