Microcystin accumulationandantioxidantresponsesinthefreshwater clam Diplodonchilensispatagonicus upon subchronicexposuretotoxic Microcystis aeruginosa

SABATINI, S.E.; BRENA, B.; LUQUET, C.M.; SAN JULIÁN, M.; PIREZ, M.; RÍOS DE MOLINA, M.C.

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: San Diego, California; Año: 2011 vol. 74 p. 1188 - 1194

0147-6513

We investigated the accumulation and toxicity of microcystin-LR (MCLR) in the digestive gland of the freshwater clam Diplodon chilensis patagonicus. Treated clams were fed with a toxic strain of Microcystis aeruginosa (NPJB1) during 6weeks and control clams received the non-toxic strain NPDC1. Filtration rate was estimated for both groups.Toxic effects were evaluated through the hepatosomatic index (HSI) and different oxidative stress biomarkers, lipid peroxidation (content of thiobarbituric reactive substances–TBARS), proteinoxidation (carbonyl groups) and reduced glutathione (GSH) levels, and enzymatic activities of superoxide dismutase (SOD), catalase(CAT) and glutathione-S-transferase (GST). The extractable MCLR measured by ELISA in digestive gland extracts showed little or no change during the first 3weeks and increased significantly at weeks 5 and 6. HSI was reduced by 30% in treated clams at weeks 5 and 6. No significant oxidative damage to lipids or proteins was observed. All the antioxidant defense parameters analyzed were significantly increased at week 5 or 6. GSH increased in treated clams at week 5, reaching 62% increase at week 6. SOD, CAT and GST activities were significantly increased in treated clams by 50% ,66% and 60%, respectively, at the end of the experiment. D. chilensis patagonicus can be exposed to prolonged cyanobacterial blooms accumulating significant quantities of MCLR, which could be a risk for mammals and birds, which feed on this species and, in a lesser extent, to humans.