Different Efficacy of Nanoparticle and Conventional ZnO in an Animal Model of Anxiety

• Published in: Neurophysiology (New York) Vol. 45; no. 4; pp. 299 - 305
• Main Authors: Torabi, M., Kesmati, M., Harooni, H. E., Varzi, H. N.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.07.2013; Springer; Springer Nature B.V
• Subjects: Animal cognition; Biomedical and Life Sciences; Biomedicine; Brain; Nanoparticles; Neurobiology; Neurosciences; Rodents; Zinc oxide; Zinc oxides; anxiety; ZnO nanoparticles; rats; plus maze
• ISSN: 0090-2977; 1573-9007
• DOI: 10.1007/s11062-013-9372-7

As has been shown, trace element supplementation by zinc, e.g., in the form of zinc oxide (ZnO), can significantly influence the anxiety level. We investigated the effects of ZnO in the form of nanoparticles (NPs) in comparison with conventional ZnO (cZnO) in an animal model of anxiety. Adult male Wistar rats were divided into seven groups, control (receiving 0.9% saline) and six groups receiving 5, 10, and 20 mg/kg ZnO NPs and 5, 10, and 20 mg/kg cZnO. All drugs dispersed in 0.9% saline were injected i.p.; 30 min later, the anxiety level was estimated according to the results of the elevated plus maze test. ZnO NPs (5 mg/kg) and cZnO (10 and 20 mg/kg) significantly increased the normalized values of time spent in open arms (open arm time, OAT, %) in comparison with the control group ( P < 0.05). This is indicative of the anxiolytic effects of these components; in addition, 20 mg/kg ZnO NPs reduced the intensity of locomotor activity ( P < 0.05). The serum zinc concentration was increased manifold by anxiolytic doses of the components. All doses increased serum pH to 8.05-8.10 and kept this index constant for 24 h. These results indicate that the anxiolytic effect of ZnO NPs is much more intense than that of conventional ZnO, but the introduction of ZnO NP as a new drug for the treatment of anxiety disorders needs further investigations.