Modulation of immune and antioxidant responses by azinphos-methyl in the freshwater mussel Diplodon chilensis challenged with Escherichia coli

CASTRO, JUAN M.; BIANCHI, VIRGINIA A.; PASCUAL, MARIANO; VENTURINO, ANDRÉS; LUQUET, CARLOS M.

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

SETAC PRESS

Año: 2016

0730-7268

The aim of this work was to characterize the immune response (total hemocyte number, cell type proportion, hemocyte viability, lysosomal membrane stability, phagocytic activity, cellular acid and alkaline phosphatase activity, and humoral bacteriolytic and phenoloxidase activity) in Diplodon chilensis exposed to 0.2 mg/L of azinphos-methyl (AZM), using Escherichia coli as immunological and prooxidant challenge. Additionally, glutathione-S-transferase (GST) and lipid peroxidation (TBARS) were analyzed in gill tissue. Mussels from an unpolluted site were treated for three days as follows: 1) Experimental control (C); 2) Solvent effects control (Ac, acetone 0.01%); 3) Bacterial challenge effects control (E. coli, 5 × 104 cells/mL); 4) Pesticide effects control (AZM in acetone); 5) Control for combined effects of solvent and bacterial challenge; and 6) Exposed to AZM and then challenged with E. coli. The results showed increased granulocyte proportion and phagocytic activity. Partial reversion of deleterious effects of E. coli on lysosomal membranes was observed in mussels exposed to AZM and then challenged with E. coli. Total hemocyte number and humoral bacteriolytic activity were increased only by E. coli challenge. Acid phosphatase activity is increased by both E. coli and AZM, while the stimulating effect of E. coli on alkaline phosphatase activity is negatively modulated by AZM. AZM inhibited phenoloxidase activity regardless of E. coli challenge. Gill GST activity was increased by E. coli treatment either alone or pretreated with Ac or AZM and by AZM alone. TBARS levels were reduced by AZM alone or combined with E. coli challenge and by acetone followed by E. coli challenge. Both acetone and AZM seem to be important modulators of immune and antioxidant responses in D. chilensis. This article is protected by copyright. All rights reserved.