Organ-specific antioxidant defenses and FT-IR spectroscopy of muscles in Crucian carp (Carassius auratus gibelio) exposed to environmental Pb2+

Authors: SHER ALI KHAN, XIAOYU LIU, HONG LI, WENTING FAN, BAKHT RAMIN SHAH, JINGNA LI, LU ZHANG, Suyan Chen, Sher Bahadar Khan

Abstract: Being a nonessential element, lead (Pb²⁺) can be toxic in trace amounts for freshwater fish. The present study was designed to evaluate the induction of oxidative stress, tissue-specific antioxidant response, acetyl cholinesterase (AchE) activities, and biochemical content of muscle in Crucian carp (Carassius auratus gibelio) after 96 h of acute exposure and 21 days of chronic exposure to various environmental concentrations (5, 10, and 30 µg L^-1) of waterborne Pb²⁺. The results indicated that exposure to 10 and 30 µg L^-1 Pb²⁺ significantly altered the activities of catalase, superoxide dismutase, and glutathione peroxidase in different tissues, while malondialdehyde content increased in a time- and concentration-dependent manner. Inhibition of AchE after chronic exposure also confirmed a generalized neurotoxic stress. Fourier transform infrared spectroscopy revealed mild changes in the structure of proteins and lipids, whereas the integrated biomarker response indices signified the liver, kidneys, and gills as the responsive organs to environmental Pb²⁺ exposure.

Keywords: Crucian carp, heavy metal, Pb2+, fish, oxidative stress, Fourier transform infrared spectroscopy, integrated biomarker response

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