Methyl paraben application on rainbow trout (Oncorhynchusmykiss) hepatotoxic effects

This study was carried out to evaluatethe findings of oxidatives stres-mediated hematoxicity, hepatotoxicity and nephrotoxicity caused by methylparaben in rainbow trout (Oncorhynchus mykiss). For this purpose, 96 rainbow trout (152,25±25,10 g and 20,09±1,11 cm) were used with 3 replicates, 8 fish in each group. In the study, 4 groups were formed with 3 different doses of methylparaben (1 mg/L, 5 mg/L, 8 mg/L) and a control. The hepatosomatic index decreased in the 1 mg/L dose group and increased in the 5 mg/L and 8 mg/L dose groups compared to the control group. Compared to the control group, the rate of weight gain (%) relative to the initial weight decreased as the methylparaben dose increased. An increase in serum urea and uric acid values was observed in methylparaben groups compared to the control group. The amount of MDA, one of the markers of oxidative damage, increased in parallel with the increase in methylparaben dose compared to the control group. GSH-Px enzyme levels, one of the important indicators of the antioxidant system, decreased as a result of methylparaben administration compared to the control group. Histologically, while the liver tissue in the control group was normal, a very small amount of congestion in the central vein and mild degeneration in hepatocytes were found in the 1 mg/L methylparaben group. 5 mg/L and 8 mg/L methylparaben caused sinusoidal congestion in the liver tissue, degeneration in hepatocytes, degeneration and proliferation in the bile duct, and vacuolar degeneration in the parenchymal region were found. In the control group kidney tissue, the renal corpuscle, and proximal and distal tubules were normal. In 1 mg/L methylparaben group sections, tubule epithelial degenerations and glomerular lobulation were observed. In the sections obtained from the 5 mg/L and 8 mg/L methylparaben group, diffuse degenerations in tubule epithelium, glomerular atrophy and enlargement of Bowman's cavity, necrosis, hydropic degenerations in tubules, decrease in hematopoietic tissue and increase in melanomacrophage centers were observed. Methylparaben, which is widely used in food, cosmetics, and pharmaceutical industries due to the good solubility properties of short-chain parabens, causes oxidative stress in rainbow trout when it enters the aquatic ecosystem. It also negatively affects the oxidant/antioxidant system balance and causes various lesions in liver and kidney tissues. There fore it is necessary to prevent or reduce the contamination of methylparaben, a widely used preservative in daily life, from entering the aquatic ecosystem.