Comparative Evaluation of Genotoxic Effects Induced by CuO Bulk and Nano-Particles in Nile Tilapia, Oreochromis niloticus
2016
Abdel-Khalek, Amr A.
Metal oxide nano-particles have definitely unique toxicological properties than currently investigated oxides. Therefore, this study was aimed to comparatively evaluate the genotoxicity of nano-CuO and bulk CuO particles on a model fish species Oreochromis niloticus. Fish were exposed to two selected concentrations (¹/₁₀ and ¹/₂₀ of the LC50/96 h) of both nano-CuO and bulk CuO for 30 days. Genotoxic effects associated with DNA ladder formation and chromosomal damage were investigated using DNA fragmentation and micronucleus techniques. Based on DNA fragmentation of fish hepatocytes, the two selected concentrations of bulk and nano-CuO were found to induce DNA damage. Analysis of the DNA fragments initiated by bulk CuO on agarose gel revealed DNA ladder pattern, which is commonly considered as a hallmark of apoptosis, while fish exposed to nano-CuO particles showed a molecular hallmark of necrosis which is the fragmentation of the nuclear DNA into a smear-like pattern. Also, DNA damage was further confirmed quantitatively using the image analysis software Image J. In this context, nano-CuO-treated groups exhibited a maximum DNA damage especially at the lower concentration (¹/₂₀ LC50/96 h). To ensure CuO genotoxicity, micronucleus and other nine nuclear abnormalities were studied in peripheral erythrocytes and significant (p < 0.05) elevation was observed in nano-CuO-exposed groups at the lower concentration followed by a decrease in extent of chromosomal damage at the higher concentration, while fish groups treated with bulk CuO showed a more or less dose-dependent effect.
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