Mercuric chloride‐induced oxidative stress, genotoxicity, haematological changes and histopathological alterations in fish Channa punctatus (Bloch, 1793)

Abstract

The present study was undertaken to investigate the adverse effects of mercuric chloride (HgCl2) overload in the fish Channa punctatus. Two sublethal test concentrations of HgCl2 (1/20th and 1/10th of 96 h LC50 i.e., 0.03 mg l−1 (low concentration) and 0.07 mg l−1 (high concentration), respectively, were used for exposure. Blood, liver and kidney tissues of the control and exposed specimens were sampled at intervals of 15, 30, and 45 days to assess alterations in oxidative stress, genotoxicity haematological parameters and histopathology. Significant changes in Hb%, RBC count, WBC count, antioxidant enzyme activity, i.e., superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and glutathione reductase (GR), were recorded. Micronuclei (MN) induction, nuclear abnormalities (NAs) and histopathological alterations were also observed in the exposed fish. Significant (P < 0.05) increase in the activities of SOD, CAT, GSH and GR was observed. After 45 days, a decrease in the level of GSH and GR was noticed which suggests an undermined anti‐oxidative defence system in the fish exposed to HgCl2. Histological examination of the liver and kidney showed serious tissue injury and histological alterations. Significant increases in MN and NA frequencies reveal the DNA damage in erythrocytes of fish, and haematological changes show the toxicological potential of HgCl2. The observed changes in the antioxidant defence system, genotoxicity and haematological and histological changes in the present study provide the most extensive insight into HgCl2 stress in C. punctatus.

Oxidative stress, inflammation, and steatosis elucidate the complex dynamics of HgCl2 induced liver damage in Channa punctata

“…In this study mercuric chloride can induce oxidative stress mediated DNA strand breaks which causes genotoxicity in fish Channa punctata . Similarly, Trivedi et al, 2022 2 have reported that mercuric chloride can cause genotoxicity in targeted fish. The resulting oxidative damage disrupts cellular functions, initiating lipid peroxidation in biomolecules like lipids and proteins.…”

“…A fluorescent dye 2′, 7′-dichlorodihydrofluorescein (20 µM, DCFH-DA; Sigma Aldrich, USA) was used to quantify ROS level in the blood of test fish 2 , 28 . The fluorescence intensity of stained blood cells depicts the amount of ROS generated.…”

“…Inorganic mercury is transformed into organic forms like methylmercury by bacteria in water, and this form is readily taken up by aquatic organisms. As fish consume contaminated prey or come into contact with contaminated water, mercury accumulates in their tissues, particularly in the liver and muscles.Mercuric chloride harms fishes by inducing oxidative stress, damaging cellular structures, particularly in the liver, and triggering inflammatory responses, ultimately compromising fish health and survival 2 . Additionally, mercury accumulates in fish tissues, disrupting physiological processes and posing risks to both aquatic ecosystems and human consumers.…”

Spleen gene expression is associated with mercury content in three-spined stickleback populations

“…The study of adaptation to contaminants is thus crucial for adequate environmental risk assessment. Many studies on experimental as well as wild populations have improved our understanding of how mercuric toxicity disrupts metabolic, endocrine and cellular pathways, and have provided a basis for the development of biomarkers for mercury pollution (Driscoll et al, 2013, Branco et al, 2017, Vasconcellos et al, 2021, Olsvik et al, 2021, Trivedi et al, 2022). In contrast, relatively few studies have investigated how genetic adaptation shapes the biological responses to mercury pollution and, therefore, how populations under pollution stress ultimately manage to persist (Belfiore and Anderson, 2001, Budnik and Casteleyn, 2019, Yang et al, 2020).…”

Toxicity Evaluation, Oxidative, and Immune Responses of Mercury on Nile Tilapia: Modulatory Role of Dietary Nannochloropsis oculata

“…Although MeHg is the most toxic form [ 12 ], HgCl 2 is the most common and harmful form since it can pass across biological membranes and interact with amino acids forming organo-mercury complexes [ 13 ]. The reported Hg 2+ toxicity for fish is in the form of brain oxidative stress, inhibition of hepatic biotransformation enzymes, genotoxicity in blood, and reproductive alterations [ 14 – 16 ].…”