Neuroendocrine and Eosinophilic Granule Cells in the Gills of Tilapia, Oreochromis niloticus: Effects of Waterborne Copper Exposure

Abstract

The contamination of aquatic ecosystems with copper (Cu) poses a serious threat to aquatic organisms. Although the histopathological changes caused by Cu in fish gills are well documented, knowledge about the impact of this metal in gill specific cell types, such as neuroendocrine cells (NECs) and eosinophilic granule cells (EGCs), is still limited. In the present work, Nile tilapia (Oreochromis niloticus) were exposed for 21 days to nominal concentrations of Cu (40 and 400 µg L(-1)). Stereological methods were used to estimate the volumetric density of both NECs and EGCs in fish gill filament after 3, 7, 14, and 21 days of exposure. The results showed that Cu significantly increased the relative volume of NECs, whereas the relative volume of EGCs decreased. NECs were more affected by Cu in the first 7 days of exposure, during which a greater increase in their relative volume was observed. The Cu exposure induced a progressive decrease in the relative volume of EGCs, which reached statistical significance after 14 days of exposure. An exception was observed in subepithelial EGCs with a slight increase in their relative volume after 3 days of exposure. Our findings confirm that Cu can modulate both neuroendocrine and immune systems and becomes immunotoxic after a prolonged exposure.

Effect of the Dexamethasone and the Difenihidramiana on the Degranulation of the Eosinophilic Granular Cell of Tilapia

“…A layer of loose connective tissue separates these epithelial and muscle layers from an outer layer of fibrous connective tissue that has smooth muscle cells, capillaries, and EGCs [19]. In contrast to the roles played by monocytes, macrophages, neutrophils, and lymphocytes, the roles of EGCs in teleosts are areas of controversy [20,21]. Functionally, EGCs show great similarity to mammalian mast cells.…”

Effects of Oat Bran Addition on the Growth Performance and Intestinal Health of Nile Tilapia (Oreochromis niloticus) Exposed to Copper Ions

“…Copper is an important trace element involved in many biological processes. However, copper ions at high concentrations in water can be toxic to aquatic life [ 2 ]. Studies have shown that the accumulation of copper ions in fish can induce antioxidant damage and stress responses in tissues and organs and affect their growth, development, and reproduction [ 3 ].…”