Oxidative Stress and Immunopathological Alterations of Clarias gariepinus Exposed to Monocyclic Aromatic Hydrocarbons (BTX)

Abstract

This study’s goal was to assess the catfish’s response to exposure to monoaromatic petroleum hydrocarbons (benzene, toluene, and xylene) and its recovery after exposure using oxidative stress, histopathological, and immunological changes as biomarkers. Four groups: one as control and other three exposed to benzene (0.762 ng/L), toluene (26.614 ng/L), and xylene (89.403 ng/L), respectively, for 30 days and then recovery period for 30 days. The levels of the cortisol, lipid peroxidation, and cytokines (IL-1β, IL-6) increased significantly (p < 0.05) after exposure to benzene and xylene compared to control. Superoxide dismutase (SOD), total antioxidant capacity (TAC), and acetylcholinstease (Ach) decreased significantly (p < 0.05) in fishes exposed to benzene only compared to control group. While glutathione-S-transferase (GST) did not show any change in different treatment groups compared to control group. The histopathological signs of liver exposed to benzene, toluene, and xylene displayed aggregation of melanomacrophages, congestion of sinusoids, vacuolar degeneration of hepatocytes, necrotic area with inflammatory cell infiltration, and thrombus of central vein. Kidney exposed to benzene, toluene, and xylene showed dilatation of Bowman’s space with atrophy of glomerular tuft, lyses of RBCs with mononuclear cell infiltration, multifocal area of hemopoietic tissue necrosis, organized thrombus with perivascular hemorrhage, focal inflammatory cellular reaction, renal tubular necrosis, and thrombus of blood vessels. Spleen exposed to benzene, toluene, and xylene showed hyperplasia of lymphoid follicles in white pulp in a mild degree. These lesions appeared to a mild degree or disappeared completely after recovery period to BTX except spleen. In conclusion, monocyclic aromatic hydrocarbons (BTX) are hazardous to fish and the toxicity level was as benzene > xylene > toluene even though after recovery period.

Prefeeding of Clarias gariepinus with Spirulina platensis counteracts petroleum hydrocarbons-induced hepato- and nephrotoxicity

“…The histopathological abnormalities in the liver and kidney of exposed groups are in the same line with those reported in the studies of Sayed et al 7 , 8 . As a consequence of loss of antioxidant defensive shield to fight damaging free radicals and increase in death-mediated proteoses 52 , 53 , and following the observations of Sayed et al 7 , 54 , our results revealed presence of necrotic alterations in the liver of benzene group and epithelial sloughing in the kidney of benzene and toluene groups.…”

“…The levels of antioxidant enzymes in the liver were higher in fish treated with benzene as opposed to those treated with toluene and xylene. The heightened toxicity of benzene attributed to its elevated vapor pressure 8 . Another investigation explored the response of Clarias gariepinus to exposure to monoaromatic petroleum hydrocarbons, utilizing oxidative stress, histopathological changes, and immunological alterations as biomarkers.…”

“…The study identified benzene as the most toxic compound, followed by toluene and xylene. These findings were attributed to the increased stability and longer lifespan of benzene, making it more accessible to exposed animals compared to the other components 8 .…”

“…Its omnivorous consumption pattern and preference for depth-dwelling prey are significant attributes to consider when monitoring hazardous chemicals that build up in bottom debris 4 . It is frequently employed as a model in petrochemical pollution studies 5 – 8 , 9 due to several reasons. Firstly, it exhibits a broad tolerance range and adaptability to various environmental conditions, making it suitable for studying the impacts of pollutants in diverse aquatic habitats 10 , 11 .…”