Histopathological study on gills of Rhamdia quelen juveniles submitted to chronic toxicological test with ibuprofen

Abstract

The present study aimed at evaluating histopathological changes in gills of Rhamdia quelen juveniles submitted to different concentrations of ibuprofen (0.0; 0.5; 5.0 and 50.0 mg/L); concentrations were determined from LC₅₀ acute assays of 5.0 mg/L (120h). For each concentration four replicates were made, with four copies each.  The experiment had a total duration of 120 hours in a chronic toxicological trial. After completion, the animals were euthanized, laparotomized, and the gills were localized, isolated and fixed in 10% formaldehyde, preserved in 70% alcohol and subsequently submitted to histological routine technique for paraffin inclusion. Five cuts (6µM) per specimen were made and stained with Hematoxylin and Eosin (H&E). The Average Alteration Score (AAS) and Histopathological Alteration Indices (HAI) were determined according to the degree of the lesion and then classified in stages I, II and III which produced respectively Lamellar derangement, Lamella’s epithelium rupture and aneurysm with more expressive alterations. For all concentrations the drug led to histological alterations for Rhamdia quelen, putting in evidence damages that go from moderate to severe in the gills of the analysed fishes. Ibuprofen caused branchial lesions in R. quelen with a progressive effect in high concentrations, suggesting that the presence of this drug could cause abnormalities and favour mortality in this species.