Effects of Subchronic Manganese Chloride Exposure on Tambaqui (Colossoma macropomum) Tissues: Oxidative Stress and Antioxidant Defenses
2013
Gabriel, Diogo | Riffel, Ana Paula K. | Finamor, Isabela A. | Saccol, Etiane M. H. | Ourique, Giovana M. | Goulart, Luis O. | Kochhann, Daiani | Cunha, Mauro A. | Garcia, Luciano O. | Pavanato, Maria A. | Val, Adalberto L. | Baldisserotto, Bernardo | Llesuy, Susana F.
This study aimed to evaluate oxidative stress parameters in juvenile tambaqui (Colossoma macropomum) exposed to 3.88 mg l⁻¹ Mn²⁺ for 96 hours. Biomarkers of oxidative stress, such as thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), and glutathione-S-transferase (GST) activities, as well as content of reduced glutathione (GSH), were analyzed in gill, liver, brain, and kidney. The presence of Mn²⁺ in the water corresponded to increased levels of Mn²⁺ accumulation according to the following sequence: gill > kidney > brain > liver. There was a significant increase in TBARS levels (40 %) and SOD activity (80 %) in addition to a significant decrease in GSH content (41 %) in gills of fish exposed to waterborne Mn²⁺. In hepatic tissue of the exposed animals, TBARS levels decreased significantly (35 %), whereas SOD (82 %) and GST activities (51 %) as well as GSH content (43 %) increased significantly. In brain of exposed juvenile fish, only significant decreases in SOD (32 %) and CAT activities (65 %) were observed. Moreover, the kidney of exposed fish showed a significant increase in TBARS levels (53 %) and a significant decrease in SOD activity (41 %) compared with the control. Thus, the changes in biomarkers of oxidative stress were different in the tissues, showing a specific toxicity of this metal to each organ.
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