Ultrastructure of the epithelium that lines the ductuli efferentes in domestic equidae, with particular reference to spermatophagy.

The research investigates the cellular structure and activity of the ductuli efferentes lining in horses, donkeys, and mules, suggesting its involvement in fluid absorption, digestion, as well as a direct interaction with germ cells through spermatophagy.

Study of the Epithelium in Ductuli Efferentes

• The research observed the cellular structure of ductuli efferentes in Equidae species—horses, donkeys, and mules. The epithelium, or surface tissue, in the ductuli efferentes consists of ciliated and non-ciliated columnar cells. Also present are lymphocytes, macrophages, and ‘lipofuscin-rich’ cells. The latter contain an abundance of residual bodies and are considered a distinct feature of the excurrent ducts in the Equidae family.

Function and Morphology of the Epithelium

• The general morphology of the epithelial cells, especially the non-ciliated ones, indicates that these cells partake in the absorption and digestion of fluids within the ducts. This conclusion comes from the presence of a complex apparatus for endocytosis (the process by which cells ingest substances) and a large group of lysosomal structures located within the cytoplasm of these cells.
• The cells forming the epithelium appear to have a direct impact on germ cells through a process known as spermatophagy, which refers to the ingestion and destruction of sperm cells.

Role of Peroxisomes

• This study highlights the unusual presence of peroxisomes in non-ciliated cells. Peroxisomes are small organelles in the cells that perform various metabolic processes such as breaking down fatty acids and detoxifying harmful substances.
• The presence of peroxisomes is proposed to be linked with endocytic and spermatophagic activities. They may be involved in the oxidation of toxic peroxides, effectively serving a detoxifying function.