Effects of uranium on the oxidative state and antioxidant defense in the bioindicator snail Pomacea canaliculata

ISRAEL A. VEGA; CAMPOY DÏAZ, ALEJANDRA D;; MALANGA, GABRIELA

Congreso; VIII Congreso Argentino de la Sociedad de Toxicología y Química Ambiental.; 2022

The freshwater gastropod Pomacea canaliculata has been proposed as a bioindicator species of uranium (U) pollution since its digestive gland accumulated preferentially this element. In order to advance in the development of a toxicodynamic model, we evaluated the oxidative stress, damage, and antioxidant defense after acute exposure at a relevant ecologically U concentration. Adult snails (6 months males and females) were exposed 96 h to 700 micrograms of U (as uranyl UO2+) by liter of water. Snails were sacrificed at 0, 24, 48, 72 and 96 h after exposure. Elemental concentration was analyzed by neutron activation. Reactive oxygen species (ROS) production by oxidation rate of 2?7?-dichlorodihidrofluorescein diacetate (DCFH-DA) was used as oxidative stress parameter. The generation of lipid radicals (LR) measured by Electron Paramagnetic Resonance (EPR) and the tissue protein damage measure by carbonyl groups concentration were cellular damage markers . Non-enzymatic (α-tocopherol, α-T; β- carotene; β-C) and enzymatic (glutathione-S-transferase, GST; catalase, CAT) antioxidant defenses were also evaluated. U concentration increased significantly (a two-fold raised, compared with non-exposed) after exposure (96 h), which was accompanied by a percent increase in the LR generation (+148%) and DCFH-DA oxidative rate (+209%). Protein carboxylation reached (+150%) at the end of the exposure. The α-T and β-C content fell within the first 24 h and remained low at 96 h. The CAT enzymatic activity showed a significant increased at 72 h, but then returned their basal activity at 96 h. The GST activity decreased between 24 and 48 h, but returned to basal levels at 72 h. These findings indicate that the U acute exposure generates an oxidative stress in the digestive gland of P. canaliculata, overcoming the antioxidant defenses of the animal and causing damage to lipids and cellular proteins. Some digestive gland biomarkers may be used for a toxicodynamic modeling after aquatic exposure.