Accumulation of milk increases the width of tight junctions in the epithelium of mouse mammary alveoli

The study of the molecular mechanisms of maintaining the integrity of the epithelium during mechanical stress remains a relevant problem in the physiology of tissue barriers. A methodical approach has been applied which makes it possible to reproduce mechanical pressure on the apical region of cells in vivo and to study the participation and role of tight junctions in maintaining the integrity of the epithelial structure. Mammary gland tissue specimens from lactating control mice and animals after a 20-h interruption of suckling were prepared and the width of the tight junction of the secretory epithelium was analyzed. At the ultrastructural level, it was shown that accumulation of milk caused a significant increase in the width of the tight junction between epithelial cells. In the control group, the width of this structure was 2.1 ± 0.1 µm; in the experimental group — 4.2 ± 0.1 μm. The marked increase in the width of tight junctions between epithelial cells is in accordance with an observed increase in the level of claudin-1 and -3 in the secretory epithelium and can be interpreted as adaptive changes aimed at maintaining the structure of the alveoli.

Morphometric indices of secretory epithelium of main prostate glands in people 13-88 years old

The aim of the study was to study the age-related changes in the epithelium of the end pieces of the prostate main glands, in all its structural lobules in the age range from adolescence late adulthood age. Materials and methods. Histological, morphometric methods were used to study the secretory epithelial cells of the end pieces of the main glands on prostate preparations of 77 men aged 13-88 years, on autopsy material. The histological sections were stained with hematoxylin and eosin, studied using a Leica DM-2000 microscope with a video projection system, using the Leica "LAS V3.6" application morphometric program. Shape and sizes of the secretory epithelial cells of the end pieces of the prostate main glands in pairs of anteromedial, superomedial, inferoposterior, inferolateral structural lobes (zones) were determined. To evaluate the results obtained, nonparametric methods of mathematical statistics were used (Wilcoxon W-test for comparison of two independent samples, Kraskel-Wallis H-test for multiple comparisons, Dann's test with Bonferroni amendment). Results. The differences of the morphometric parameters of secretory epithelial cells in pairs of anteromedial, superomedial, inferoposterior, inferolateral structural lobes (zones) of the human prostate within each of the studied age periods and changes of these parameters according to the age periods from adolescents to late adulthood age were detected. Conclusion. The development and growth of secretory epithelium in all structural lobules of the prostate were observed in the age interval 13-35 years, and the atrophic processes begin at the age of 36, but these changes occur asynchronously, both within one end piece of the gland and in different structural lobules. The changes of the epithelium in the prostate does not always correspond to the calendar age of men.

Key molecules in the GABA signalling pathway are present in mouse and human cervical tissue

Cervical mucus modulates fertility by cyclical changes of its biophysical and functional properties. Based on an analogy with bronchial goblet cells we set out to investigate the possible role of the gamma-aminobutyric acid (GABA) signalling pathway in the mediation of oestrogen-induced mucus secretion from endocervical secretory cells. The aim of the study was to examine the existence of GABAA receptor (GABAAR), glutamic acid decarboxylase 65/67 (GAD65/67) and vesicular GABA transporter (VGAT) in human and mouse cervical tissue. The mouse cervical tissue expressed GabaAR mRNA transcripts throughout the oestrous cycle. GABAAR-positive immunolabelling was present in the superficial layer of the mouse cervico–vaginal epithelium in pro-oestrus. Human cervical tissue showed the presence of GABAAR, GAD67 and VGAT mRNA transcripts and clear immunofluorescent signals of all three molecules were detected in the endocervical secretory epithelium. The results of this study confirmed that elements of the GABA signalling pathway are present in the secretory epithelium of mouse and human cervical tissue and that GABA signalling pathway could be considered a possible mediator in oestrogen regulation of mucus secretion in the endocervical glands.

Immunohistochemical Localization of Elastic System Fibres in the Canine Prostate

The elastic fibres are particularly important for the structural integrity and function of the prostate. In this study, the elastic fibres of the normal dog prostate gland were identified by immunohistochemistry. In the capsule, the elastic fibres form membranes of different thicknesses-located mainly in the intermediate and deep zones. Large trabeculae which extend from the capsule contain elastic fibres with a prevalence in the longitudinal direction. Around blood vessels, the elastic fibres are concentrated and form annular structures. In the fine septa supporting the lobules, elastic fibres form a fine elastic meshwork. Between the secretory units of the prostate gland, the fine elastic fibres are located under the secretory epithelium. An increase of elastic fibres around the ducts entering the urethra was observed. An accumulation of elastic fibres in the capsule and stromal septa may participate in the releasing of secretory products during ejaculation.