First observations of histopathological effects of 2,4,6-trinitrotoluene (TNT) in gills of European eel Anguilla anguilla (Linnaeus, 1758)

Abstract

The aim of the present study was to investigate the effects on gill morphology of the explosive 2,4,6-trinitrotoluene (TNT) in a model fish, the European eel, Anguilla anguilla (Linnaeus, 1758) to assess potential detrimental effects in marine fish due to its presence in dumping areas. Juvenile specimens of A. anguilla were exposed in vivo for 6 and 24 h to 0.5, 1 and 2.5 mg/l nominal concentrations of TNT using dimethyl sulfoxide (0.1 per thousand) as solvent carrier. Histological analysis of gills indicated that TNT induced several structural lesions. After 6h of exposure at 0.5 and 1 mg/l TNT, oedema of some secondary lamellae was evident: this change at the highest dose of 2.5 mg/l led to epithelial lifting and detachment from the endothelium and rupture of the branchial membrane and vascular congestion. After 24 h at 0.5 mg/l, increased oedema in secondary lamellae, extensive epithelial detachment and vascular congestion and dilation of lamellar capillaries and pooling of blood at 1 mg/l were observed. At 2.5 mg/l, epithelial hyperplasia, fusion of adjacent lamellae, obliteration of interlamellar spaces by means of tight junctions were also observed. Moreover, chloride cells proliferated along secondary lamellae, and mucus hypersecretion was evident. The overall results clearly indicate that gills are sensitive targets of TNT.

Humic acid of commercial origin causes changes in gill morphology of silver catfish Rhamdia quelen exposed to acidic water

“…Conditions of osmotic and ionic stress prompt CC to inundate the lamellae in order to improve Na + , Cl − , and Ca 2+ uptake (Perry, ). Once in the lamellae, these cells are closer to the bloodstream and ion absorption is optimized (Laurent, Hõbe, & Dunel‐Erb ; Goss, Laurent, & Perry, ; Greco, Gilmour, Fenwick, & Perry, ; Greco, Fenwick, & Perry, ; Perry, ; Sensini, Torre, Corsi, & Focardi, ). Nonetheless, this causes a thickening of the blood‐to‐water diffusion barrier and thus impedes the diffusion of respiratory gases through the PVC (Bindon et al., ; Greco et al., , ; Perry, ; Mazon, Cerqueira, & Fernandes, ; Moron, Oba, Andrade, & Fernandes, ; Sakuragui et al., ).…”

Histological and antioxidant responses inRhamdia quelensedated with propofol

“…Fish gills act as an interface between the organism and the aquatic environment, thus being the primary uptake site for substances dissolved in water (Cengiz ). Histopathological gill analyses have shown detrimental effects caused by organic toxicants, such as haemorrhages with rupture of epithelium, epithelial hyperplasia and fusion of adjacent lamella (Sensini, Torre, Corsi & Focardi ). Extensive gill changes may impair physiological function, rendering the fish unable to osmoregulate, ventilate and maintain acid‐base balance (Wendelaar‐Bonga ).…”

“…; Sensini et al . ), for example. Once in the lamella, the chloride cells are closer to the bloodstream, which helps sustaining ion uptake.…”

Histopathological changes in the gills and liver of Prochilodus lineatus from the Salado River basin (Santa Fe, Argentina)

“…The literature indicates that a variety of toxicants (organochlorates, polycyclic aromatic hydrocarbons, organophosphate compounds, carbamates, miscellaneous herbicides, acidification, nitrogenous compounds and heavy metal salts) in the aquatic environment can affect gill structure and function (Metcalfe 1998;Wood 2001;Elahee and Bhagwant 2007;Sensini et al 2008). Gill pathologies can result in the suppression or inhibition of physiological function, irrespective of whether the pathologies are caused by chemical, physical or secondary parasitic irritation (Schlacher et al 2007).…”

“…This facilitates an efficient gas and ion respiratory exchange, but at the same time forms a large and sensitive target area for toxicants (Wendelaar Bonga and Lock 2008). Gills are highly susceptible to adverse environmental conditions, and damage in gill epithelia has been considered as a good indicator of xenobiotics effects on fish (Oropesa-Jiménez et al 2005;Ballesteros et al 2007;Sensini et al 2008;Korkmaz et al 2009). …”