The effect of dexamethasone on the occurrence and ultrastructure of rodlet cells in goldfish

In the bulbus arteriosus of goldfish Carassius auratus a subendothelial ‘reticular space’ was comprised of reticular-like cells, neutrophils, medium-sized granular leucocytes, phagocytes, endothelial cells and reticulo-endothelial cells; herein, rodlet cells (RCs) accumulated and probably matured. Four classes of RCs were identified: (1) Those occurring in the reticular space and contacting reticular-like cells; (2) those present in the reticular space contacting reticular-like and endothelial cells; here the RCs were discharging; (3) those occurring in the bulbar lumen anchored to lining endothelial cells or other RCs; (4) those free in the bulbar lumen. There was no significant difference in the number of RCs among control and saline- and dexamethasone-treated fish, but significant differences were found in RCs' class partition and in their discharge modality. In dexamethasone-treated goldfish class (3) RCs were almost absent (2%v. 10% of the other experimental groups), moreover 35% of the RCs developed a ‘bleb’ discharge modality rather than the most typical ‘koronenartigen konfiguration’ which developed in the vast majority (90%) of the other experimental groups.[...]