Abstract
Abstract:The goal of these study was to evaluate the toxicity and severity of Zinc Oxide nanoparticle(ZnO-NPs) in gills tissue so Cyprinus carpio exposed to sub lethal concentration of ZnO-NPs 9mg/l for (7, 14, 21, 28, 35, 42) days cause histopathological and ultra structural alteration in gills tissue. Microscopic examination revealed hemorrhage and clup shape of epithelial cells that lining the secondary gill filament through (7 and 14 days of treatment), hyperplasia in mucus cells with hyper trophy of pillar cells at 28 days of treatment, and at day 42 the lesions were character by basement thickening in the secondary gill filament with edema and vacuolar degeneration of pillar cells. While ultra structural examination revealed presences cloudy swelling of chloride cells and condensation of micro organelles at 7 days of exposure ,the severity of lesions were increased with prolong time of exposure so at day 14 of exposure to ZnO-NPs the electron microscope examination exhibit thickening of blood vessels ,hyperplasia of mucus cells with vacuolar degeneration of chloride cells .Ultra structural changes in gills tissue of fish that exposed to N-ZnO for 42 days revealed microvilli and adhesion of micro ridge with degeneration of lining epithelial cells in the secondary gill filaments. In conclusion, ZnO-NPs are toxic in a concentration of 9mg/l in a common carp (Cyprinus carpio), that manifested by histopathological and ultra-structure alteration in gills and there was a positive relationship between the severity of lesions and time of exposure.
Highlights
Nanoparticles (NPs) are several small-scale substances that must attain specific optical, mechanical, electrical and magnetic properties for a wide range of applications
Gills pathology in our study agreements with the result of Subashkumar and Selvanayagam (2014), they reported the pathological changes in gills of Cyprinus carpio exposed to different sublethal concentration of ZnONPs for 21 days
Electron microscopy analyzes considered as a tool in the monitoring of fish exposed to contaminants and biological indicators for the initial signs of alterations tissue that difficult to detect in morphologically or macroscopic examination
Summary
Nanoparticles (NPs) are several small-scale substances (usually < 100 nm) that must attain specific optical, mechanical, electrical and magnetic properties for a wide range of applications. Nanoparticles(NPs) vary in origin, size and content which lead to changes in biological function as altered in respiratory rate, mucus secretion, and toxic effects in gills and internal organs may involve oxidative stress and ion regulatory disturbances (Handy et al, 2011).ZnO-NPs are one of the most common nanomaterials which is widely produced and applied in many products mainly in cosmetic product and wastewater treatment (Chen et al.,2004; Handy and Shaw,2007). The researchers Jin–Ling et al, (2011) wrote about the toxic effect of ZnO-NPs on Acanthopagrus schlegelii that cause ultrastructure changes in gills of common carp with hemorrhage and vacuolar degeneration in the kidney (Chupani et al, 2018). There are many studies about the effect of ZnO NPs on human and other vertebrates. A study of the toxic effect of ZnO NPs on fish has been few
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