Neural stem cells isolated from activated brain neurogenic niches after traumatic injury demonstrate distinct behaviors in vitro

The subventricular zone (SVZ) of the lateral ventricle and subgranular zone (SGZ) of the dentate gyrus (DG) in the hippocampus represents neurogenic niches within the brain housing distinct populations of neural stem cells (NSCs), known for their exclusive capacity to sustain neurogenesis in the adult mammalian CNS. These niches respond to traumatic brain injury (TBI) by becoming activated, leading to NSC proliferation, a small number of which subsequently migrate towards the injury site, and differentiate predominantly into astrocytes. Although the capacity of activated NSCs to differentiate into neurons appears to be limited, it is intrinsically interesting to determine whether these cells may represent a potential source of new neurons that may replenish and replace damaged and lost neuronal tissue. To address this question, it is necessary to understand the intrinsic behavior of NSCs derived from the activated SVZ and SGZ neurogenic niches after TBI, in terms of cell maturation, and differentiation capacity. In this study, we induced a focal TBI lesion specifically targeting the SVZ or SGZ neurogenic niche in adult rats, harvested NSCs three days post-lesioning, and subsequently expanded them in culture. We found that the isolated NSCs displayed distinct proliferation, differentiation, and spontaneous organization in vitro, dependent on the activated niche of origin. Furthermore, these behaviors differed from NSCs derived from the SVZ or SGZ niche of uninjured control animals.