Cardiac, reproductive, and brain toxicity of zinc oxide nanoparticles in male rats: Focus on morphological alterations and oxidative stress markers

Our bodies are exposed to different types of nanoparticles in our daily routine. Hence, this experiment aimed to measure the effects of different doses of zinc oxide nanoparticles (ZnO NPs) on various organs in Wistar rats. Wistar rats were randomly divided into 6 groups as follows: group 1: control, group 2: control rats +5 mg/kg ZnO NPs, group 3: control rats +10 mg/kg ZnO NPs, group 4: control rats +25 mg/kg ZnO NPs, group 5: control rats +50 mg/kg ZnO NPs, and group 6: control rats +100 mg/kg ZnO NPs. The ZnO NPs were administrated orally for one month, and then the heart, hippocampus, and testis were removed and used for more analysis. The malondialdehyde (MDA) levels, total oxidant status (TOS), and total antioxidant capacity (TAC) were measured. For histological analysis, the tissues were analyzed by hematoxylin-eosin staining. TAC significantly decreased in the hippocampus, heart, and testis of rats treated with 10-100 mg/kg ZnO NPs compared to the control (P < 0.05). The TOS and MDA levels significantly increased by 25-100 mg/kg ZnO NPs compared to the control (P < 0.05). Histological findings show that the structure of the hippocampus, heart, and tissues in the rats received 5 was similar to the healthy control rats. While, 25-100 mg/kg ZnO NPs had harmful effects on these tissues. Our findings show that high dosages of ZnO NPs induce oxidative stress and histopathological changes in the hippocampus, heart, and testis.