Influence of season and pollution on the antioxidant defenses of the cichlid fish acará (Geophagus brasiliensis)
Braz. j. med. biol. res
;
34(6): 719-26, Jun. 2001. ilus, graf
Artigo
em Inglês
| LILACS
| ID: lil-285844
RESUMO
The livers of Geophagus brasiliensis collected from both a non-polluted site and a polluted site were analyzed for different antioxidant defenses, O2 consumption, thiobarbituric acid-reactive substance (TBARS) levels, and histological damage. Compared to controls (116.6 + or - 26.1 nmol g-1), TBARS levels were enhanced at the polluted site (284.2 + or - 25.6 nmol g-1), as also was oxygen consumption (86.6 + or - 11.3 and 128.5 + or - 9.8 µmol O2 min-1 g-1, respectively). With respect to enzymatic antioxidants, increased catalase activities (8.7 + or - 1.3 and 29.2 + or - 2.4 mmol min-1 g-1, respectively), unchanged superoxide dismutase activities (767.2 + or - 113.3 and 563.3 + or - 70.2 U g-1, respectively), and diminished glutathione S-transferase activities (29.0 + or - 3.2 and 14.9 + or - 3.2 µmol min-1 g-1, respectively) were detected. Reduced glutathione (1.91 + or - 0.17 and 1.37 + or - 0.25 mM, respectively), oxidized glutathione (1.50 + or - 0.20 and 0.73 + or - 0.17 mM, respectively), and total glutathione (3.40 + or - 0.26 and 2.07 + or - 0.27 mM, respectively) concentrations were also below control values at the polluted site. Nevertheless, the observed ethoxyresorufin-O-deethylase activities (1.34 + or - 0.11 and 16.7 + or - 0.21 pmol min-1 mg-1, respectively) showed enhanced values at the polluted site. The main histological damage observed in the hepatocytes from fish collected at the polluted site was characterized by heavy lipid infiltration. Fish collected at the end of spring showed higher O2 consumption, higher superoxide dismutase and glutathione S-transferase activities, and higher total and oxidized glutathione concentrations compared to the beginning of autumn. No seasonal changes were observed in catalase activities, glutathione or TBARS levels. Fish chronically exposed to relatively high pollution levels seem to be unable to set up adequate antioxidant defenses, probably due to severe injury to their hepatocytes. The higher antioxidant defenses found at the end of spring are probably related to the enhanced activities during high temperature periods in thermoconforming organisms.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Estações do Ano
/
Poluição da Água
/
Percas
/
Adaptação Fisiológica
/
Antioxidantes
Limite:
Animais
País/Região como assunto:
América do Sul
/
Brasil
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2001
Tipo de documento:
Artigo
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade Federal de Santa Catarina/BR
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