Detoxification and Antioxidant Responses in Diverse Organs of Jenynsia multidentata Experimentally Exposed to 1,2- and 1,4-Dichlorobenzene.”

MONFERRÁN, MAGDALENA V; PESCE, SILVIA F; CAZENAVE, JIMENA AND WUNDERLIN, DANIEL A.

ENVIRONMENTAL TOXICOLOGY

Wiley (Interscience)

Lugar: Jackson USA; Año: 2008 vol. 23 p. 184 - 192

1520-4081

Abstract We report changes in activities of detoxification and antioxidant enzymes as well as lipid peroxidation levels in liver, gills, and brain of Jenynsia multidentata exposed to 1,2- and 1,4-dichlorobenzene (DCBs). Fish were captured at an unpolluted area, transported to the laboratory, and acclimated  previous to experiments. Exposures were carried out using 1,2-DCB at 0.5, 1, 5, and 10 mg·L- 1 and 1,4-DCB at 0.05, 0.1, 1, and 5 mg·L-1. After 24 h exposure, fish were sacrificed and dissected separating liver, gills, and brain of each fish. Organs were used for enzyme  extractions, evaluating antioxidant system through the assay of glutathione reductase (GR),  guaiacol peroxidase (POD), glutathione peroxidase (GPx), catalase (CAT) as well as  detoxification system by measuring glutathione-S-transferase (GST) activity. Additionally,  thiobarbaturic acid reactive substances (TBARS) method was used to evaluate the  peroxidation of lipids (LPO) No changes in GST activity was found in liver of fish exposed to DCBs but in gills and brain of exposed fish, with an earlier activation of the detoxification system of fish  exposed to 1,2-DCB than those exposed to 1,4-DCB. Antioxidant response is activated in liver at low DCBs concentrations, followed by a drop at highest levels. We also found activation of the antioxidant system in gills and brain of exposed fish. On the other hand, we did not observe changes in TBARS concentrations in liver or gills of exposed fish with respect to controls, but in brain of fish exposed to 1,2-DCB (0.5 mg·L-1) and 1,4-DCB (5 mg·L-1). Responses of both detoxification and antioxidant systems of J. multidentata suggest that 1,2-DCB is more toxic than 1,4 DCB to this specie. To the extent of our knowledge, this is the first report of oxidative stress induced by DCBs in fish. Our results evidence that the brain is the organ most severally affected by the oxidative stress caused by DCBs.