Biomarker responses in Corbicula fluminea to the presence of dioxin-like polychlorinated biphenyls and seasonal changes
Апстракт:
PCBs are potential genotoxicants and inductors of increased levels of
ROS and oxidative stress in both humans and wildlife. In this study,
biotransformation parameters and antioxidant (AO) enzymes were analyzed
in the Asian clam, Corbicula fluminea, with respect to the presence of
dioxin-like PCBs (dl-PCBs) in the environment. For this purpose, clams
were collected from three localities with different environmental
conditions. Sediments from each locality and clam tissues were analyzed
for the presence of dl-PCBs. Biological responses included changes in
the expression of fish CYP1A immunoreactive protein, changes in the
activities of AO enzymes, SOD, CAT, GR and GPx, and the phase II
biotransformation enzyme GST. Clams from the locality with the highest
EWHO TEQ values for sediment dl-PCBs had the highest EWHO TEQ values for
tissue dl-PCBs and the highest level of fish CYP1A immunoreactive
protein expression. The correlations found between the concentrations of
dl-PCBs and AO and GST activities revealed both concentration-dependent
inhibitory and stimulatory effects. The activities of GPx, GR and GST
were very sensitive to environmental xenobiotics, including dl-PCBs. The
obtained results indicate that the activities of these enzymes were
fine-tuned to provide optimized antioxidant responses. We also observed
seasonal changes in GST and AO enzyme activities in Asian clam. The
highest levels of activity were observed in spring as compared to summer
or autumn. CDA, which was performed in order to classify the different
clam populations, revealed a coordinated rearrangement of the clams'
metabolic components that were probably aimed at compensating for
environmental fluctuations. The presented data reveal the sensitivity of
C. fiuminea to the presence of dl-PCBs in the environment and support
the use of this clam as a sentinel species for biomonitoring studies.
(C) 2014 Elsevier Ltd. All rights reserved.