Abstract
This study aimed to investigate the toxicity of oral ZnONPs on the rat's lung. Rats were divided into four groups each of ten rats. Groups I and II were treated orally with 40 and 100 mg/kg ZnONPs for 24 hrs. Groups III and IV received daily 40 and 100 mg/kg ZnONPs orally for 1 week. Ten untreated rats were used as control. Oral administration of ZnONPs induced eosinophilia and lymphocytes infiltration in the lungs in the four tested groups that peaked at 100 mg/kg/day for 1 week. Lipid peroxidation was significantly higher, while levels of reduced glutathione and catalase activity were lower in all ZnONPs-treated groups. Nitrite concentrations increased significantly in rat's lung treated with 100 mg/kg for 24 hrs and in those treated with 40 and 100 mg/kg daily for 1 week. Levels of lung TNF-alpha were significantly higher after 24 hrs at high dose and after 1 week at both low and high doses. Interleukin-1 beta and pentraxin-3 levels were significantly increased at 1 week only at both low and high doses. There were lower levels of paraoxonase-1 and increased DNA damage in the four studied groups. Oral administration of ZnONPs induced lung injury possibly through oxidative stress, inflammatory response and DNA damage.