Integration of the Neural Stem and Progenitor Cells into Existing Neuronal Circuitry and Adult Neurogenesis in the Dentate Gyrus of the Hippocampus

Abstract

Objective: For a long time there was a central dogma that new neurons are not generated in the adult mammalian brain. But nowadays, it is well accepted that new neurons are continuously generated in discrete neurogenic regions of the brain throughout adult life. Neurological disorders are characterized by neuronal cell death, glial scar formation, axonal damage and deterioration of the cerebral cytoarchitecture and neuronal circuitry which result in functional deficits. Since the promising strategy for regenerating the damaged central nervous system (CNS), is the activation and recruitment of the endogenous regenerative capacity, therefore we investigated the neurogenesis potential of endogenous neural stem cells in an adult mouse brain. Methods and Materials : Since the some documented experimental studies have shown that the long-term injection of the BrdU induces cell senescence and astroglial differentiation, in the present study, BrdU intraperitoneal injection was applied in a short period of time. The number of animals sacrificed for evaluation of the proliferation of neural stem and progenitor cells and 4 weeks following the last BrdU injection, the rest of the animals was used for investigation of adult neurogenesis. Results : Findings showed that the neural stem and progenitor cells produce in the subgranular zone (SGZ) of the dentate gyrus and after 4 weeks differentiate into mature neurons. Also, this experiment showed that the possibility of the evaluation of adult neurogenesis mechanism will be provided with BrdU injection in a short time. Conclusion : The generation and integration of new neurons is a continuous physiological process that occurs in the brain. Therefore, the use of endogenous neural stem cells is a promising approach for neural tissue regeneration in the neurological conditions.