Hematoepidimal barrier: morphological, physiological, immunological, seasonal aspects, effects of destabilizing factors

The aim of this review was to analyze the literature on the morphofunctional organization of the hematoepididymal barrier. Spermatozoa that have come from the testis into its appendage cannot actively move and do not have the ability to fertilize. These functions of spermatozoa are acquired in the appendage of the testis, where a special environment in its lumen is created by components of the hematoepidimal barrier as a result of limiting paracellular transport, stimulating receptor-mediated transport of macromolecules through the epithelium of the appendage. The hematoepidimal barrier includes a pseudostratified columnar epithelium lying on the basement membrane, loose connective tissue of the mucous membrane's own plate and capillary endothelium located on the basement membrane.

The leading role in the functioning of the hematoepidimal barrier is played by apical tight contacts between neighboring main cells of the pseudostratified epithelium, as well as adhesive contacts between them. The constituent components of dense contacts are transmembrane proteins, which include several families. The vascular part of the hematoepidimal barrier is represented by a continuous endothelium lying on a continuous basement membrane. Interactions of dendritic cells, macrophages and lymphocytes play an important role in regulating the permeability of the hematoepidymal barrier along with the epithelial and vascular components. The adaptive capabilities of the hematoepidimal barrier allow it to show resistance to the action of many negative factors. A violation of the function of cellular connections in the hematoepidimal barrier is one of the factors of male infertility.