Assessment of Genotoxic, Oxidative Stress and Histopathological Effects of Azo Dye Acid Red 119 on Blood and Gill of Freshwater Fish Channa punctata

The unregulated release of azo dyes from textile industry effluents into freshwater systems constitutes a serious environmental and toxicological concern. The current investigation was undertaken to elucidate the acute toxicological impact of Acid Red 119 (AR 119) in the blood and gill of freshwater fish Channa punctata, using a multi-tiered biomarker approach encompassing genotoxic, biochemical, and histopathological endpoints. Experimental exposures involved two sub-lethal concentrations of AR 119-15.90 and 31.81 mg/L-administered over a 96 h period. The results revealed a dose-dependent and statistically significant increase in frequencies of micronucleated cells, nuclear and cellular abnormalities, and DNA damage, evidenced by elevated values of comet assay parameters such as tail length and %tail intensity, tail moment, and olive tail moment. Biochemical analysis demonstrated a significant elevation in MDA content, indicating increased lipid peroxidation, along with alterations in SOD and GST activities in blood and gill tissues. The effects were more pronounced at the higher concentration (31.81 mg/L), especially after 96 h of exposure. Histopathological analysis further showed gill tissue damage, including aneurism, epithelial lifting, vacuolization, and fusion of secondary lamellae. Taken together, these findings demonstrated that AR 119 exerts marked genotoxic and oxidative stress in C. punctata, underscoring the urgent need for stricter effluent regulation and sustainable treatment strategies in textile industries.