Objective: 

In adult rats, the endogenous neurogenesis is maintained in the subventricular zone and the dentate gyrus of the hippocampus and could be used to improve post-stroke outcome. Here we asked if stimulations of endogenous neurogenesis before or after stroke in aged rats, which are known to be more severly affected by stroke than young rats, may improve recuperation after stroke.

Methods: 

Stroke was induced by middle cerebral artery occlusion (MCAO) in aged rats and neurogenesis was stimulated at different time points using neurogenesis enhancer, pentylentetrazole or electrical stimulation. After MCAO, rats were behaviorally tested for 7 weeks and global gene expression and immunhistochemical analyses of the periinfacted region were done.

Results: 

Our results indicate that stimulation of neurogenesis at 4 weeks before stroke does not improve post-stroke outcome. In contrast, stimulation of post-stroke neurogenesis is beneficial for behavioral recovery of aged rats. Global gene expression analysis has shown many new feature of gene expression associated with aging and led to identification of over 400 new genes involved in stroke pathophysiology. Immunohistochemistry has revealed many new features related to the neurovascular unit in the aged post-stroke animals.

Conclusions: 

Stimulation of post-stroke neurogenesis is beneficial for behavioral recovery of aged rats.