Experimental designs: (A) Schematic timeline of the experimental procedures; (B) mice were monitored in hypoxic conditions (8% O2) controlled with N2 gas for 90 min after unilateral carotid artery ligation; (C) in the left and middle panels, the damaged brain showed an ipsilateral lesion in the posterolateral hemisphere, while the right panel in the red box shows that severely injured mice were excluded from this study; and (D) an enriched environment, including tunnels, shelters, toys, running wheels for voluntary exercise, and social interaction and standard cage at the right bottom.