Alternative toxicity mechanisms of hepatotoxin (microcystin) in the estuarine crab Chasmagnathus granulata (Decapoda, Grapsidae) Oxidative stress.

20. PINHO G; MOURA C, YUNES J; LUQUET C; BIANCHINI A; MONSERRAT J.

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. TOXICOLOGY & PHARMACOLOGY

Elsevier

Lugar: x; Año: 2003 vol. 135 p. 459 - 468

1532-0456

Microcystins are toxins produced by cyanobacteria, being toxic to aquatic fauna. It was evaluated alternativemechanisms of microcystins toxicity, including oxidative stress and histopathology in the hepatopancreas of the estuarinecrab Chasmagnathus granulatus (Decapoda, Grapsidae). Microcystins was administered to crabs (MIC group) over 1week, whereas the control (CTR group) received the saline from cyanobacteria culture medium. At day 7, catalaseactivity was higher in the MIC than in the CTR group, although a decrease of activity was verified in both groups withrespect to time 0. Glutathione-S-transferase activity augmented in MIC with respect to CTR, suggesting a higherconjugation rate of the toxins with glutathione. No differences were detected in the superoxide dismutase activity. Lipidperoxidation remained stable in both groups. Histopathological analyses showed that the number of B cells decreasedsignificantly in the CTR as a possible effect of starvation, while no significant change was observed in the MIC group.The hepatopancreas from the MIC group exhibited some necrotic tubules and melanin-like deposits. Overall, resultsshowed that some enzymes of the antioxidant defense system were activated after microcystins exposure, this responsebeing able to maintain lipid peroxidation levels, but insufficient to completely prevent histological damage.