Antioxidant responses to benzo[a]pyrene, tributyltin and their mixture in thespleen of Sebasticus marmoratus
WU Yu-qiong , WANG Chong-gang , WANG Yun , ZHAO Yang , CHEN Yi-xin , ZUO Zheng-hong
DOI:
Received November 21, 2006,Revised January 18, 2007, Accepted , Available online
Volume 19,2007,Pages 1129-1135
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It has been reported that there is an interaction between Benzo[a]pyrene (BaP), a widespread carcinogenic polycyclic aromatic
hydrocarbon, and tributyltin (TBT), an organometal used as an antifouling biocide. This study was therefore designed to examine
the potential in vivo influence of BaP, TBT and their mixture on splenic antioxidant defense systems of Sebastiscus marmoratus.
The fish were exposed to water containing environmentally relevant concentrations of BaP, TBT and their mixture. Spleens were
collected for biochemical analysis after exposure for 7, 25, 50 d and after recovery for 7, 20 d. Cotreatment with BaP and TBT for 7 d
potentiated the induction of glutathione peroxidase (GPx) activity by BaP or TBT alone. The cotreatment for 25 and 50 d resulted in
inhibition of GPx activity, which was similar to the e ect of TBT. Splenic glutathione S-transferase (GST) activities were significantly
elevated in S. marmoratus exposed to BaP starting from 7 d and remained high up to 25 d. However, no further activity change was
found with prolonged exposure. Cotreatment of BaP and TBT primarily inhibited the GST activity, which was similar to the e ect
of TBT. Cotreatment with BaP and TBT for 25 or 50 d potentiated the depletion of GSH (glutathione) by BaP or TBT alone. MDA
(malondialdehyde) contents in spleen of S. marmoratus were not significantly altered compared with the control during the test period.
Spleen, as an immune organ, is sensitive to exposure of BaP or TBT. It should have an e ective mechanism to counteract oxidative
damage. Antioxidative defense systems in spleen of S. marmoratus should be considered as potential biomarkers. Short-term exposure
of BaP or TBT could result in induction of antioxidant defense system. A significant decrease of these indices, such as GSH, GST, GPx
might indicate more severe contamination.
