Objective: To investigate the changes of neural stem cells (NSCs) in the rat hippocampus after cerebral infarction (CI) and to evaluate the neurogenesis caused by the activation of NSCs.
Methods: CI models of rats were made and rats were assigned to 6 groups: sham-operated, 1 day, 3 days, 7 days, 14 days, and 28 days after CI. The dynamic expression of bromodeoxyuridine (BrdU), polysialylated neural cell adhesion molecule (PSA-NCAM), glial fibrillary acidic protein (GFAP), and neuronal nuclear antigen (NeuN) were determined by immunohistochemistry and immunofluorescence staining. BrdU was used to mark the proliferated NSCs. PSA-NCAM was used to mark the plasticity of activated NSCs. GFAP and NeuN were used to mark the differentiated NSCs.
Results: Compared with the controls, the number of BrdU+ cells in the hippocampus increased significantly at 1 day after CI (P < 0.05), reached peak at 7 days after CI (P < 0.05), decreased but still elevated compared with the controls at 14 days after CI (P < 0.05), and nearly unchanged at 28 days after CI. The number of BrdU+/PSA-NCAM+ cells increased significantly at 7 days after CI (P < 0.05), reached peak at 14 days after CI (P < 0.05), and decreased but still elevated compared with the controls at 28 days after CI (P < 0.05). The number of BrdU+/PSA-NCAM+ cells was equal to 60% of the number of BrdU+ cells in all the same period. The number of BrdU+/NeuN+ cells in the hippocampus increased significantly at 14 days after CI (P < 0.05) and reached peak at 28 day after CI (P < 0.05). The number of BrdU+/GFAP+ cells in the hippocampus nearly unchanged after CI.
Conclusion: CI can stimulate the proliferation of inherent NSCs, and most proliferated NSCs may differentiate into neurons and represent neural plasticity.