peculiarities > rodlet cells

The rodlet cell is particular cell type which has been described in association with various organs in teleosts. In H&E staining, it has a bright cytoplasm with, depending on the plane of section, coarsly striated or punctuated eosinophilic (rod-like) structures. The small nucleus has an excentric location. The intracellular rod-like structures of rodlet cells have a positive reaction with periodic acid-Schiff (PAS), which makes them even more easily discernible.
In the RIVM's zebrafish stock, rodlet cells were observed in a number of organs:

- thyroid (interspersed between follicular cells):

gill (probably subepithelial) and gill associated lymphoid tissue:

thymus (also with a subepithelial location):

gut (associated with the germinative layer of the epithelium): liver (associated with small blood vessels):

The rodlet cell has been designated as enigmatic, and there is still debate about its role. The following examples illustrate the diversity of postulated functions for which clues were found (mainly in morphological studies):
  1. Grunberg W, Hager G. [Ultrastructural and histochemical aspects of the rodlet cells from the bulbus arteriosus of Cyprinus carpio L. (Pisces: Cyprinidae)]. Anat.Anz. 143:277-290;1978
  2. Fishelson L, Becker K. Rodlet cells in the head and trunk kidney of the domestic carp (Cyprinus carpio): enigmatic gland cells or coccidian parasites? Naturwissenschaften 86:400-403;1999.
  3. Dezfuli BS, Simoni E, Rossi R, Manera M. Rodlet cells and other inflammatory cells of Phoxinus phoxinus infected with Raphidascaris acus (Nematoda). Dis.Aquat.Organ 43:61-69;2000.