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

CASTRO J.M.; BIANCHI V.A.; PASCUAL M.; VENTURINO A.; LUQUET C.M.

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

SETAC PRESS

Lugar: Buenos Aires; Año: 2017

0730-7268

The aim of the present study 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 humoralbacteriolytic and phenoloxidase activity?in Diplodon chilensis exposed to 0.2 mg/L of azinphos-methyl (AZM), using Escherichia colias immunological and pro-oxidant challenges. In addition, glutathione-S-transferase and lipid peroxidation thiobarbituric acid reactivesubstances were analyzed in gill tissue. Mussels from an unpolluted site were treated for 3 d as follows: 1) experimental control; 2)solvent effects control (acetone 0.01%); 3) bacterial challenge effects control (E. coli, 5 cells/mL x 104 cells/mL); 4) pesticide effectscontrol (AZM in acetone); 5) control for combined effects of solvent and bacterial challenge; and 6) exposed to AZM, then challengedwith 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 andhumoral bacteriolytic activity were increased only by E. coli challenge. Acid phosphatase activity was increased by both E. coli andAZM, whereas the stimulating effect of E. coli on alkaline phosphatase activity was negatively modulated by AZM. Azinphos-methylinhibited phenoloxidase activity regardless of the E. coli challenge. Gill glutathione-S-transferase activity was increased by E. colitreatment either alone or pretreated with acetone or AZM and by AZM alone. Thiobarbituric acid reactive substance levels were reducedby AZM alone or combined with the E. coli challenge and by acetone followed by the E. coli challenge. Both acetone and AZM seem tobe important modulators of immune and antioxidant responses in D. chilensis.