Zinc Oxide Nanoparticles attenuate Cadmium Chloride induced tongue toxicity in adult male albino rats (Histological and Biochemical study)

Introduction: Cadmium is a toxic heavy metal naturally present in plant food and unavoidable pollutant for many dental procedures. This metal shares in toxic peroxidation and destruction of macromolecules in different tissues, besides inhibition of DNA repair enzymes. The tongue is one of the vital organs that could be affected by chronic cadmium toxicity, especially the filiform papillae and tongue skeletal muscles due to their high metabolic activity. Aim of work: to study the possible role of Zinc oxide nanoparticles (ZnO NPs) in attenuation of the structural, ultra-structural and biochemical changes in rats' tongues induced by Cadmium chloride. Materials and Methods: sixty adult male Albino rats were divided equally -according to the utilized substance- into three groups; control, Cadmium chloride (CdCl) and (CdCl+ ZnO NPs) groups; every group received the allocated materials for 4 weeks. Samples were processed for light, electron microscopic examinations and biochemical analysis (malondialdehyde; reduced glutathione; catalase; superoxide dismutase; glutathione peroxidase). Results: Cadmium produced various apparent histopathological and biochemical alterations in tongue tissues in the form of filiform papillae with blunted ends, and thick keratin plaques. Epithelial cell layers appeared with vacuolated cytoplasm and dark nuclei. Degenerated muscle fibrils with wide spaces between them and many collagen fibers. Significant decrease of tongue reduced GSH, SOD, GPx and Cat enzymes activity and significant increase in MDA level in Cadmium chloride group as compared to control group. ZnO NPs attenuated these changes and revealed pointed tipped filiform papillae, nearly normal cells and Parallel arrangements of myofibrils. The levels of reduced GSH, SOD, GPx, Cat and MDA were insignificant compared to control group. Conclusion: Zinc oxide nanoparticles (ZnO NPs) attenuated the structural and biochemical changes in rats' tongues induced by Cadmium chloride.