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

Abstract

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.

Dose- and Segment-Dependent Disturbance of Rat Gut by Ionizing Radiation: Impact of Tight Junction Proteins

“…Tight junctions (TJs), apical complexes connecting neighboring cells in barrier tissues, are known to provide the mechanical binding of enterocytes into a single layer, as well as paracellular transport control [ 11 , 12 , 13 ]. The key molecular components of TJs are proteins of the claudin family, which consists of 27 members in mammals, and the TJ-associated MARVEL-domain-containing protein (TAMP) family, primarily including occludin and tricellulin [ 14 , 15 ].…”

Selective Role of TNFα and IL10 in Regulation of Barrier Properties of the Colon in DMH-Induced Tumor and Healthy Rats

“…One of the functions of TJs is to combine epithelial cells into unified sheets and maintain the integrity of the epithelial layer [ 27 ]. Under conditions of possible disintegration of TJs, the expression of claudins changes [ 28 ]. Therefore, one of the features of carcinogenesis, in particular in the colon, is a change in the expression of TJ proteins [ 29 , 30 , 31 , 32 ].…”