Histopathological Effects of Fonofos on Gills of Zebrafish (Danio rerio)
Abstract
Organophosphate pesticides are commonly used to increase agricultural
efficiency worldwide. However, it has been proved that these chemicals
generally do not show target specificity and non-target vertebrate organisms
are adversely affected by pesticide exposure. The aim of the present study was
to examine the potential harmful effects of fonofos, an organophosphate
insecticide, on the gill tissues of zebrafish (Danio rerio). Adult zebrafish were exposed to 1, 2 and 4 mg/L
fonofos for 96 hours. Gill tissues were removed, fixed with Bouin’s fluid and
embedded in paraffin. 5 µm serial sections were stained with hematoxylin-eosin,
Gomori trichrome or periodic acid-Schiff. Samples were investigated by light
microscopy and histological alterations were compared with the 0.1% dimethyl
sulfoxide (DMSO) exposed solvent control samples. Fonofos caused epithelial
lifting, curling of secondary lamellae, desquamation, epithelial hyperplasia,
and lamellar fusion in the gills. Gills showed distinct histopathological
changes through fonofos exposure. It was determined that fonofos is a threat to
non-target organisms living in aquatic ecosystems.
Keywords
Fonofos,insecticide,gill,histopathology,zebrafish,Danio rerio
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