The blood-epididymis barrier and inflammation

Abstract

The blood-epididymis barrier (BEB) is a critical structure for male fertility. It enables the development of a specific luminal environment that allows spermatozoa to acquire both the ability to swim and fertilize an ovum. The presence of tight junctions and specific cellular transporters can regulate the composition of the epididymal lumen to favor proper sperm maturation. The BEB is also at the interface between the immune system and sperm. Not only does the BEB protect maturing spermatozoa from the immune system, it is also influenced by cytokines released during inflammation, which can result in the loss of barrier function. Such a loss is associated with an immune response, decreased sperm functions, and appears to be a contributing factor to post-testicular male infertility. Alterations in the BEB may be responsible for the formation of inflammatory conditions such as sperm granulomas. The present review summarizes current knowledge on the morphological, physiological and pathological components associated with the BEB, the role of immune function on the regulation of the BEB, and how disturbance of these factors can result in inflammatory lesions of the epididymis.

Keywords:

• ABC transporters
• claudins
• defensin
• granuloma
• sperm maturation

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Acknowledgments

We wish to thank Dr. Dianne Creasy (Huntington Life Sciences) for her generous contribution of granuloma photomicrographs. J. Dufresne (INRS) is thanked for her assistance.

Funding

This work was supported by CIHR (grant 84576).