Liver histopathology of the fish brachydanio rerio hamilton-buchman after acute exposure to sublethal levels of the organophosphate dimethoate 500

Abstract

ABSTRACT. Among the new substances that were synthesised by the chem ical industlY during the last decades, with the aim to improve human prosperity, some cause negative effects on non target organisms like fish. Among the pesticides, the organophosphates (OP) are w idely used in cattle management, agriculture and aquaculture activi ties. Brachydania reria Hamilton-Buchman, 1822 is used world-wide in fishtests for the establishment of the lethal levels of pesticides. Nevertheless, these fi sh show mo rphological changes in their hepatocytes when exposed experimentally for 24 hours to the sublethal dose of 0.025 fli /l of the OP Dimethoate 500, in ac ute tests.Eight hours after exposure, a high density ofeells with cytoplasmic granulation is seen as well as focal necrosis. The main changes that occurred in the first 24 hours of exposure we re the loss of the typical polygonal ce ll shape and of detec tab le cell limits, lateral migration of nuclei, nuclear size and shape, condensati on of chromatin and pycnosis, increased cytoplasm ic granulation followed by vacuo li sati on. After 48 hours in clean water, 72 hours ti'om contaminati on, besides significant morpho logica l changes and necrosis, focal regeneration of the hepatocytes, canaliculi , ducts and sinusoids were seen. Even having been exposed to the half of the dose considered as safe according to the general pesticide allowance rules, significant changes of the liver ti ssue were obselved.

Effects of the organophosphorous methyl parathion on the branchial epithelium of a freshwater fish Metynnis roosevelti

“…The toxicity of methyl parathion is the result of a metabolic conversion processed in the endoplasmic reticulum of the hepatocytes, where the group P=S is transformed into P=O. This process affects directly the morphology of the hepatocytes (Rodrigues and Fanta, 1998). The resultant compound, paraoxon, is responsible for the inhibition of several enzymatic systems (colinesterase, carboxilase, acetylcolinesterase and mitochondrial oxidative phosphorilase).…”

Gills of juvenile fish piaractus mesopotamicus as histological biomarkers for experimental sub-lethal contamination with the Organophosphorus Azodrin®400

“…Among the known pesticides, organophosphates (OPs) are extensively used in agriculture all over the world (Pehkonen and Zhang, 2002;Rodrigues and Fanta, 1998;Saleha Banu et al, 2001;Samuel and Sastry, 1989;Sogorb and Vilanova, 2002;Thangnipon et al, 1995). The OP used in this study was Azodrin ® 400 that contained the active principle monocrotophos.…”

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“…2012), congestions of sinusoids (Langiano & Martinez. 2008;Gawish, Issa, & Ali, 2011;Shiogiri et al, 2012), necrosis (Rahman, Hossain, & Mollah, 2002;Gu imaraes, Silva de Assis, & Boegera, 2007;Velmu rugan, Selvanayagam, Cengiz, & Unlu, 2009) and hemorrhages (Rodrigues & Fanta, 1998;Langiano & Martinez. 2008) in livers of many fish species.…”