Oxidative stress and histopathological alterations are early biomarkers of Pb-induced damage in Gilt-head Bream (Sparus aurata, L.)

Resumen

Our aim was to assess the potential induction of oxidative and histopathological damage after a waterborne Pb-exposure in gills, muscle, liver and brain of Sparus aurata. Juvenile fish were grouped in 30 L tanks and exposed under laboratory conditions for 24 or 96 hours to nominal Pb concentrations of 0 (controls), 0.01, 0.1, 1 and 10 ppm by adding Pb(CH3COOH)2). Pb concentrations were analysed in samples from water by ICP-AES or DPASV and in fish tissues by ICP-MS. A set of biomarkers of oxidative damage were evaluated, including Hydroperoxides (HP) levels, superoxide dismutase (SOD) and catalase (CAT), and histopathological alterations. Pb concentrations (mg/Kg d.w.) observed in tissue ranged 0.33-28.16 (gills); 0.014-5.24 (brain); 0.011-2.83 (liver), 0.026-0.339 (muscle). Gills showed the higher Pb content, followed by brain and liver, the lowest was in muscle. HP content was increased in all the organs, but the higher levels were observed in gills and brain (24h and 96 h). SOD activity was increased in gills, liver and brain; but it was inhibited in muscle. CAT activity was increased in descending order gills>liver>brain. Lesions as steatosis, blood cells accumulation and cellular atrophy leading to parenchyma disorganization were detected in liver. Gills showed alterations as oedemas, aneurysms, hypertrophy of lamellar epithelia, epithelial desquamation. These results suggest that a short-term Pb exposure caused an accumulation of the metal with histopathological damages, the induction of oxidative stress, and an organ specific antioxidant response, which may serve as early biomarkers of Pb toxicity in fish in environmental monitoring.