Journal: |
J. Egypt. Acad. Soc. Environ. Develop.,
J. Egypt. Acad. Soc. Environ. Develop.,
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Volume: |
20
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Abstract: |
Copper oxide nanoparticles (CuO NPs) are commonly used in many industrial and
biomedical applications. Excessive usage of these products may lead to their discharge into
aquatic ecosystems causing harmful ecotoxicological hazards. The present study was
performed to assess the impact of CuO NPs on mortality, bioaccumulation, oxidative stress,
histopathology of the hepatopancreas and DNA damage of the red swamp crayfish
Procambarus clarkii. The assessment of such effectsof Cu NPs may be useful for
understanding the mechanism of their toxicity and evaluation of the possibility of using
nanoparticles-induced alterations in the investigated organism as pollution biomarkers. For
these purposes, adult crayfishes were exposed to 25, 125 and 250 mg/l of CuO NPs for 28
days. Percentages of mortalities were 0%, 6.7% and 36.7%, for application of these
concentrations respectively. Bioaccumulation analysis revealed that the highest accumulation
levels of copper were observed in gills followed by hepatopancreas while the lowest was
detected in muscles. Biochemical analysis showed that exposure of P. clarkii to the above
concentrations of CuO NPs caused significant increase in the activities of lipid peroxidation
(LPO), Catalase (CAT), Glutathione-S-transferase (GST) and Metallothioneins (MTs) in
hepatopancreas. On the other hand, levels of glutathione (GSH), total lipids (TL) and total
proteins (TP) were significantly decreased. Light microscopical examinations of the
hepatopancreas exposed to CuO NPs revealed lumen dilatation, increased yellowish brown
granules, vacuolation, nuclear pyknosis and cellular lysis in the hepatopancreatic epithelial
cells. At the electron microscopiclevel, vacuolated cytoplasm with densely stained secretory
granules, fragmented microvilli of absorptive cells, ruptured RER, and deformed
mitochondria were noticed. Comet assay analysis showed that high concentrations of these
nanoparticles caused nuclear DNA damage. In conclusion, CuO NPs induced many
histopathological and biochemical alterations in P. clarkia which are clear enough to be used
as biomarkers for CuO NPs exposure.
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