Environmental exposures influence the integrity of the blood-testis barrier.
Biological barriers play important roles in protecting tissues and organs from harmful environmental exposures. Examples of such barriers are found in the brain, retina, placenta, skin, and testes. Authors of a 2021 review describe the blood-testis barrier and enumerate compounds that may influence the barrier’s health and function.
The blood-testis barrier is composed of Sertoli cells, a type of epithelial cell that provides support to the seminiferous tubules, the site of spermatogenesis. Sertoli cells are polarized, giving them distinct properties and providing an arrangement that prevents the movement of large molecules across the cell. An array of structures links the Sertoli cells, including tight junctions, ectoplasmic specializations, desmosomes, and gap junctions.
Exposure to environmental contaminants may negatively influence blood-testis barrier function. For example, methamidophos, a type of pesticide, damaged the barrier and disturbed sperm production in rodents. Similarly, bisphenol AF, a compound used in plastic manufacturing, damaged sperm DNA and induced genetic and epigenetic changes in fish. Furthermore, pro-inflammatory cytokines, such as tumor necrosis factor alpha and transforming growth factor beta-3, disturbed the tight junctions that comprise the barrier, increasing permeability. Other compounds that may harm the blood-testis barrier include androgens, chemotherapeutic agents, and cadmium.
However, some dietary compounds may protect the barrier. For example, vitamins C and E ameliorated some of the harmful effects of exposure to air pollution, and selenium improved Sertoli cell viability and promoted the production of anti-inflammatory cytokines.
The blood-testis barrier is one of the tightest biological barriers found in mammals, likely due to its crucial role in reproduction. Evidence suggests that environmental exposures influence the health and integrity of the blood-testis barrier, but much of the research has been conducted in animals or in in vitro studies. Further study in humans is necessary to fully elucidate the factors that affect the blood-testis barrier.
Read our overview articles to learn more about other biological barriers, such as the blood-brain barrier and the intestinal epithelium.
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