Histopathological effects of zinc oxide nanoparticles (ZnO) on skin and muscle tissues of rats

Although ZnO nanoparticles possess novel properties that make them available to a wide range of applications, the questions regarding their safety may arise when they come in  direct contact with biological systems (such as skin, lungs, and tissues). In this study, we evaluated the possible toxic effects of different dosages of zinc oxide nanoparticles (25, 50 and 100 mg/kg) in three treatment groups in four weeks on skin and muscle tissues of treated rats. For toxicological assessments, male rats weighing 150 to 200 g were exposed to three  different concentrations of zinc oxide nanoparticles (25 , 50 and 100mg/kg) in an acute study.Toxic responses were assessed by clinical and histopathologic parameters. In all experimental animals the sites of exposure were scored for any type of dermal toxicity and compared with the negative control group. All changes were compared with the negative control group and the results were analyzed by one-way analysis of variance (ANOVA). Results have been  indicated that the  mean levels of the histopatological injuries were scored in experimental groups and showed no significant difference with control group that mean,the number of vacuole degeneration showed significant increase in high dose group  (p<0.05). The results showed that the topical  application  of zinc oxide can not make remarkable effects on the skin and skeletal muscle tissue of the rats in low and medium doses. Although, we did not find any harmful effects on the use of low and medium dosages of zinc oxide nanoparticles on the skin and musculoskeletal system, we can not ignore the observations regarding the sensitivity of cells and tissues to the potential cytotoxic effects this kind of nanoparticles. Therefore, it is suggested to conduct further researches on the complex toxicity mechanism of zinc oxide nanoparticles in living organisms.