Oxidative stress response of scallop Aequipecten tehuelchus from Patagonia Argentina exposed to inorganic arsenic

Abstract

Laboratory studies were performed to assess the impact of acute arsenic (As) exposure on the Tehuelche scallop Aequipecten tehuelchus from San José gulf (Patagonia, Argentina). The As accumulation in gills, digestive gland and muscle of A. tehuelchus was analyzed after 96 h of exposure at different concentrations (0, 4, 5, 6.3 and 7.9 mg As/L). Accumulation in all tissues increased linearly with the exposure concentration, evidencing no As saturation. A 96 h median lethal concentration (LC50) value of 7.1 mg As/L was determined, characterizing this species as relatively tolerant to As. The potential effects of As were studied through the production of reactive species, enzymatic activities of catalase and glutathione-S-transferase, metallothioneins, lipid peroxidation, and lipid-soluble antioxidants. In presence of As, the 2’,7’-dichlorodihydrofluorescein diacetate oxidation rate and thiobarbituric acid reactive substances content did not show changes in any tissues. Catalase and glutathione S-transferase activities raised in gills and digestive gland and remained unchanged in muscle. Metallothioneins increased in gills and digestive gland and a decreasing pattern of α-tocopherol was observed in gills and muscle. Scallops were slightly affected by As exposure, especially at high levels, being able to counteract its effects by the induction of biotransformation pathways and antioxidant defense mechanisms.