Journal de cytologie et d'histologie

Origin of Rodlet Cells and Mapping Their Distribution in Ruby-Red-Fin Shark (Rainbow Shark) Epalzeorhynchos frenatum (Teleostei: Cyprinidae): Light, Immunohistochemistry and Ultrastructure Study

Abstract

Hanan H Abd-Elhafeez and Soha A Soliman

The present study describes for the first time histology, histochemistry, and ultrastructure of all rodlet stages. By ultrastructure, we identified rodlet progenitors in the stroma of the olfactory organ in Red-Fin shark. Rodlet progenitors were mesenchymal-like cells synthesis the primitive rodlet granules. Rodlet progenitors differentiated to vesicular rodlet cells, which was rich in vesicles and vacuoles, and accumulate intracellular fibrillar-like components. Granular rodlet cells were observed in the basal epithelia, contained premature rodlet granules and began to organize the fibrillar components of the rodlet capsule. Transitional rodlet cells continued to deposit the fibrils of the capsule and synthesis of rodlet granules. Mature rodlet cells were polarized bear-shape and had typical rodlet granules. Histochemistry showed rodlet cells had a wide range of staining affinities including carbohydrate, lipid, and protein staining. All stages of rodlet cells revealed the presence of PAS-positive granules in the cytoplasm of rodlet cells where, While the ruptured ones stained strongly with alcian blue, sliver stain and Sudan black B. Rodlet granule was positive for bromophenol blue Rodlet cells were positively immunostained against Matrix Metalloproteinase-9 (MPP-9) in all stages indicate invasion properties of rodlet cells in tissue. Conclusion rodlet cells originated from the stroma of the olfactory organ.