Insulin Can Improve the Normal Function of the Brain by Preventing the Loss of the Neurons

Background: Insulin promotes the expression of genes related to brain function, thus preventing the neurodegeneration process. The present study was designed to find the neuroprotective effect of insulin by reducing neuron loss in the brain. Materials and Methods: In this study, 20 adult male NMRI mice were divided into two groups: control and insulin. The control group was intact, and the insulin group received 100 ?L of insulin at a 72-hour interval by intraperitoneal (I.P.) injection for 30 days. At the end of the study, the brain was removed. The volume of the brain and the total number of neurons and glia were estimated by stereological techniques, and also the gene expression of NSR, PI3K, AKT, IGF-1, and FOXO-1 was measured using real-time PCR. Results: The results showed that the total number of neurons decreased in the control group compared to the experimental group. Furthermore, the expression of NSR, PI3K, AKT, IGF-1, and FOXO-1 genes was lower in the control group than in the insulin group. Conclusion: The results showed that treating mice with insulin prevented reducing the number of neurons and gene expression related to normal brain function. So, insulin could have neuroprotective effects against neuron loss. Insulin may be beneficial as a new approach to avoiding neuron loss in regenerative medicine.