Biochemical and histological changes in the liver tissue of rainbow trout (Oncorhynchus mykiss) exposed to sub-lethal concentrations of diazinon

Abstract

The organophosphate insecticide diazinon is widely used to control pest in Iran. The purpose of the present study was to investigate the antioxidant and histopathological changes in the liver tissue of rainbow trout (Oncorhynchus mykiss) exposed to 0.1 and 0.2 mg/L of a commercial formula of diazinon for a period of 28 days. Antioxidant enzyme activities--catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase--were determined after 7, 14 and 28 days of exposure. Histopathological analyses were performed at the 28th day. All antioxidant enzymes were induced after 7 days of diazinon treatment in both concentrations of diazinon. Catalase and superoxide dismutase maintained elevated activities during all the treatment period. Glutathione peroxidase activity returned to the control values at the 14th day, decreasing to values below control at the 28th day in both diazinon concentrations. Glutathione reductase maintained increased activities at the 14th day in the 0.1 mg/L diazinon, decreasing to control values at the 28th day. In the 0.2 mg/L group, the activity returned to control values at the 14th and decreased below the control at the 28th day. Total antioxidant capacity of hepatocytes significantly decreased in fishes exposed to diazinon during all experimental periods. Hypertrophy of hepatocytes, vacuolization of cell cytoplasm and hepatocyte cloudy swelling were observed in the liver tissue of fish exposed to both concentrations of diazinon. The results showed that diazinon altered the activity of antioxidant enzymes and the cellular total antioxidant capacity inducing oxidative stress and cellular damage in hepatocytes evidenced by histopathological analysis.

Adverse effects of organophosphorus pesticides on the liver: a brief summary of four decades of research

“…Dose-dependent liver changes, including necrosis, cytoskeleton disarray, vacuolisation of the endothelial cells, damages in Disse's space, changes in nuclear shape, and heterochromatin distribution were evidenced in the liver of fish and rats exposed to sub-lethal doses of diazinon for a long time (37,38).…”

Enzymatic Profile Aactivity of Grass Carp (Ctenopharyngodon Idella) After Exposure to the Pollutant Named Atrazine (Herbicide)

“…LDH is an enzyme that participates in the anaerobic pathway of carbohydrate metabolism. The increase of LDH activity is a diagnostic index widely used to recognize increases of anaerobic metabolism resulting from depletion of energy under anaerobic and environmental stress conditions [23][24]. The increase of LDH activity in the whole body extract of fish was a physiological mechanism to provide more energy to deal with the effects of any stress condition [23].…”

Presence of Organic Pesticides in Commercial Rainbow Trout Farms

“…Diazinone was detected in farm A in two (6.25%) samples (in 2014) in the downstream rainy season (A6), but in farm B (in 2014), it was detected in three samples (9.37%), in the rainfall: in two samples (6.25%) in the affluent (B1) and in a sample (3.12%) downstream (B9). Diazinone is a Class II (moderately hazardous) insecticide of general use [34], but moderately soluble in water, volatile, with low risk of leaching to groundwater (PPDB, 2009), however it may contaminate surface water due to agricultural activity [2,11]. Its degradation may be faster in freshwater than in seawater [13].…”