ULRASTRUCTURAL OBSERVATIONS ON EPITHELIAL PHAGOCYTOSIS OF SPERMATOZOA IN BOVINE EJACULATORY DUCT

Document Type : Research article

Author

Assiut Univ. Fac. of Vet. Med., Dept. of Anatomy & Histology

Abstract

In the present study 10 ejaculatory ducts from sexually mature healthy bovine bulls were used. The collected materials were prepared for ultrastructural examination. The process of sperm phagocytosis by the lining epithelial cells of the ejaculatory duct was examined. The spermatozoa appeared mostly embedded within a layer of fine particles of seminal plasma over the surface of an absorptive epithelium with well developed microvilli. These particles of the seminal plasma formed a fine delicate network. The spermatozoa attached with the network by darkly stained points of attachment on their surface. The spermatozoa showed different degrees of degeneration such as the separation of plasma membrane, acrosomal cap and nuclear envelope. These spermatozoa were observed at different levels over the absorptive epithelial surface, which may be a result of absorptive and pinocytotic or phagocytic activity of the covering layer. In the areas of close contact between spermotozoa and epithelium, the absorptive epithelial cells form cone-shaped elevations of cytoplasm above the cell surface. At the areas of cytoplasmic protrusions, the slender-shaped microvilli became short and few in number. Other absorptive cells showed cytoplasmic processes protruded over the surface and surrounded the spermatozoon that located in contact with the cell surfaces. At the end of phagocytic process, the absorptive epithelial cells demonstrated changes in the morphology of their apical surface and the contents of their cytoplasm. The apical border became smooth with few short microvilli. Within the cell body, engulfed spermatozoa at different stages of ingestion, and several lysosomal bodies with heterogenous contents were observed. It can be concluded that spermiophagy in bovine ejaculatory duct is undertaken by the lining columnar cells through morphological transformation from the absorptive phase into the phagocytic phase.

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