Effect of Sub-Chronic Exposure of Zinc (Zn) and Lead (Pb) on Liver Function Parameters of Channa punctatus : A Comprehensive Review

Abstract

Freshwater ecosystems in rapidly industrializing and intensively farmed regions receive continuous inputs of trace metals, among which zinc (Zn) and lead (Pb) are highly relevant because Zn is essential but toxic at elevated levels, while Pb is non-essential and strongly toxic even at low, chronic exposures. Channa punctatus (Indian murrel) is a widely distributed, air-breathing teleost frequently used as a sentinel species for biomonitoring due to its ecological tolerance, market availability, and sensitivity of biochemical biomarkers. present review synthesizes on sub-chronic Zn and Pb exposure–associated liver dysfunction in C. punctatus, focusing on functional biochemical indices (AST/SGOT, ALT/SGPT, ALP, LDH), metabolic proteins (total protein, albumin, globulin), bilirubin, lipid profiles, oxidative stress endpoints (LPO/MDA, SOD, CAT, GST, GSH), and liver histopathology. Across laboratory and field-linked studies, sub-chronic Zn exposure typically shows a dose- and duration-dependent pattern characterized by bioaccumulation in liver, induction of oxidative stress, leakage of hepatocellular enzymes into circulation, and structural lesions including hepatocyte vacuolation, sinusoidal dilation, and necrosis. Chronic Pb exposure tends to produce stronger enzyme leakage, marked protein depletion, elevated lipid peroxidation, and pronounced tissue degeneration, reflecting membrane damage, mitochondrial impairment, and impaired detoxification. Evidence also suggests that mixed-metal scenarios amplify oxidative damage and disturb redox-regulated gene responses, underlining the need to evaluate combined exposures rather than single-metal toxicity. Standardized sub-chronic protocols using environmentally relevant concentrations, time-series sampling, and integrated “biochemistry–histology–molecular” endpoints are recommended for robust risk assessment. Overall, liver function parameters in C. punctatus are sensitive early-warning biomarkers for Zn/Pb contamination and can support management of freshwater metal pollution and associated food-chain risks.