Toxic effects of microcystins in the hepatopancreas of the estuarine crab Chasmagnathus granulatus (Decapoda, Grapsidae).
Microcystins are toxins produced by cyanobacteria, being toxic to aquatic fauna. It was evaluated alternative mechanisms of microcystins toxicity, including oxidative stress and histopathology in the hepatopancreas of the estuarine crab Chasmagnathus granulatus (Decapoda, Grapsidae). Microcystins was administered to crabs (MIC group) over 1 week, whereas the control (CTR group) received the saline from cyanobacteria culture medium. At day 7, catalase activity was higher in the MIC than in the CTR group, although a decrease of activity was verified in both groups with respect to time 0. Glutathione-S-transferase activity augmented in MIC with respect to CTR, suggesting a higher conjugation rate of the toxins with glutathione. No differences were detected in the superoxide dismutase activity. Lipid peroxidation remained stable in both groups. Histopathological analyses showed that the number of B cells decreased significantly 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, results showed that some enzymes of the antioxidant defense system were activated after microcystins exposure, this response being able to maintain lipid peroxidation levels, but insufficient to completely prevent histological damage.
Pinho
G L L
GL
Departamento de Ciências Fisiológicas, Fundação Universidade Federal do Rio Grande, R. Eng Alfredo Huch 475, Rio Grande 96201-900, Brazil.
Moura da Rosa
C
C
Yunes
J S
JS
Luquet
C M
CM
Bianchini
A
A
Monserrat
J M
JM
D000818:Animals; D001427:Bacterial Toxins / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D000458:Cyanobacteria / Q000737:chemistry; D033364:Decapoda / Q000187:drug effects*; D005982:Glutathione Transferase / Q000378:metabolism; D043143:Hepatopancreas / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D006651:Histocytochemistry; D008054:Lipid Peroxides / Q000378:metabolism; D008297:Male; D008543:Melanins / Q000378:metabolism; D052998:Microcystins; D009336:Necrosis; D018384:Oxidative Stress / Q000187:drug effects; D010456:Peptides, Cyclic / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism
D001427:Bacterial Toxins; D008054:Lipid Peroxides; D008543:Melanins; D052998:Microcystins; D010456:Peptides, Cyclic; C078588:microcystin; D002374:Catalase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase