Induction of neural stem cell proliferation by iron oxide nanoparticles and magnetic field and Ki67 gene expression in rat hippocampus after ischemia/reperfusion

Ischemic stroke is considered as the second leading cause of death in the world and yet one of the causes of disability in adults. The present study aimed to evaluate the effects of iron oxide nanoparticles and the magnetic field on neural stem cells proliferation after ischemia/reperfusion in the rat model. This experimental study was conducted on a total of 50 male Wistar rats aged 6-7 weeks and weight of 220-250 g weight, which were divided into sham (i.e., ischemia-reperfusion model), control, iron oxide nanoparticles treated-, magnetic field exposed-, and simultaneously iron oxide nanoparticles and magnetic field exposed- groups. The brain ischemia/reperfusion was performed for 20 minutes by blocking the animal carotid arteries. In addition, neural stem cell proliferation was evaluated in the hippocampus of the 5 groups after 4 days by bromodeoxyuridine (BrdU) staining method. Then, the expression of Ki67 gene involved in the cell proliferation was quantitatively studied among the 5 groups by the quantitative real-time polymerase chain reaction (qRT-PCR). The results of BrdU staining revealed that iron oxide nanoparticles and the magnetic field separately increased cell proliferation after ischemia/reperfusion after 4 days in the hippocampus. However, simultaneous treatment with nanoparticles and magnetic field failed to show a significant difference compared to the sham group for 4 days. Conversely, the expression of Ki67 gene increased significantly in the group treated with iron oxide nanoparticles or the group exposed to magnetic field compared to the ischemia-reperfusion model. In general, iron oxide nanoparticles and magnetic field can separately be regarded as 2 effective methods for increasing the neural stem cell proliferation after ischemia/reperfusion.