Acute toxicity of commercial atrazine in Piaractus mesopotamicus: Histopathological, ultrastructural, molecular, and genotoxic evaluation

Abstract

Aim:The aim of this work was to evaluate the sensitivity of Pacu fingerlings (Piaractus mesopotamicus) by measuring the effects of median lethal concentration (LC50) of atrazine (ATZ - 28.58 mg/L) after acute exposure (up to 96 h).Materials and Methods:The fish were exposed to the LC50 of ATZ for 96 h (28.58 mg/L) in a static system. During the experiment, the fingerlings were randomly distributed in four glass tanks (50 L) containing dechlorinated water. Four glass tanks were for the control group, and four were for the ATZ-exposed group (n=4 per glass tank), given a total number of 16 animals tested per group. The genotoxicity was evaluated by micronucleus (MN) test in erythrocytes from peripheral blood. Qualitative and semi-quantitative histopathological analyses, and also ultrastructural study, were applied in liver and kidney samples. Finally, the content of heat shock protein (Hsp70) in the liver was evaluated by the western blotting method.Results:The morphological alterations in the liver, which was associated with increased expression of Hsp70, included nuclear and cytoplasmic vacuolization, cytoplasmic hyaline inclusions, and necrosis. The kidney presented edema and tubular cell degeneration with cytoplasmic hyaline inclusion. The semi-quantitative histopathological analyses indicated that the liver was more sensitive than kidney to ATZ-induced damage. Ultrastructural analysis showed that ATZ caused membrane alterations in several organelles and increased the number of lysosomes in hepatocytes and kidney proximal tubular cells. Nevertheless, no significant difference was observed in MN frequency in erythrocytes comparing treated and control groups.,Conclusion:These results indicated that ATZ-induced damage to the kidney and liver function, ATZ at the concentration tested did not induce a significant difference in MN frequency in Pacu erythrocytes comparing treated and control groups, and also that Pacu fingerlings may be a good bioindicator for testing freshwater contamination.

Can the exposure system adopted influence the results of the atrazine toxicity in hepatic tissue of fish?

“…Several studies have already shown that atrazine can cause histological and biochemical changes in the livers of fish (Mela et al, 2013; Santos & Martinez, 2012; Xing et al, 2012). Among the histopathological changes observed in the present study, cytoplasmic vacuolization was also observed by Paiva et al (2017) in the liver of Piaractus mesopotamicus submitted to 28.58 mg/L of atrazine in a static system for 96 h. While Xing et al (2012) observed this alteration in carp liver exposed to 4.28, 42.8, and 428 μg/L of atrazine in a semi‐static system. Hepatocyte vacuolization is associated with the inhibition of protein synthesis, energy depletion, the disintegration of microtubules, changes in the use of substrates (Hinton, 1990), and disturbances in lipid metabolism (Mela et al, 2013).…”

Alleviating effects of β‐glucan inOreochromis niloticuson growth performance, immune reactions, antioxidant, transcriptomics disorders and resistance toAeromonas sobriacaused by atrazine

“…The reduction in total protein concentration was notable after exposure to ATZ in O. niloticus (Hussein, El‐Nasser, & Ahmed, ), grass carp (Khan et al, ) and common carp (Khalil et al, ). Reduced protein levels in ATZ‐exposed Pacu fingerling might be promoted by kidney and liver damage, delaying synthesis in the liver or causing elimination by the kidneys (de Paiva et al, ). Supplementation of βG with ATZ resulted in higher levels of protein, similar to the control, which may clarify the protective role of βG on the liver (Ozdemir, Toplan, Tanriverdi, & Sunamak, ).…”

Nanopesticides in Agriculture: Benefits and Challenge in Agricultural Productivity, Toxicological Risks to Human Health and Environment

“…Atrazine, intensely used in corn and sugarcane crops, is an environmental persistence pesticide, and due to its adverse impact on soil and aquatic ecosystems, it causes great concern. In Brazil, level nine times up at permitted (2 µg•L −1 ) has often registered in hydrographic basins [80,81]. The toxicity and potential risks of atrazine to aquatic fauna were investigated by the sensitivity measurement of Pacu (P. mesopotamicus) fingerlings for a dose of atrazine equivalent to LC50.…”

“…The results showed that the liver was the organ with more severe damage. Although the number of micronuclei and nuclear abnormalities has remained unchanged, atrazine has induced cellular stress in the liver and kidney [80]. The potential toxicity of atrazine on Asian clam (C. flumineausing) was assessed, and the results showed that the atrazine affected the biotransformation mechanism and caused oxidative and DNA damage but did not present any relevant change in antioxidants defenses [82].…”