Early disruptions of the blood–brain barrier may contribute to exacerbated neuronal damage and prolonged functional recovery following stroke in aged rats

We examined the effects of age on stroke progression and outcome in order to explore the association between blood–brain barrier (BBB) disruption, neuronal damage, and functional recovery. Using middle cerebral artery occlusion (MCAO), young (3 months) and aged (18 months) rats were assessed for BBB disruption at 20 min post-MCAO, and 24 h post-MCAO with tissue plasminogen activator induced reperfusion at 120 min. Results showed that BBB disruptions in aged rats occurred early and increased nearly two-fold at both the 20 min and 24 h time points when compared to young animals. Neuronal damage in aged rats was increased two-fold as compared to young rats at 24 h, while no neuronal damage was observed at 20 min. Young and aged rats exhibited neurological deficits when compared to sham-controls out to 14 days following MCAO and reperfusion; however, aged rats exhibited more severe onset of deficits and prolonged recovery. Results indicate that aged rats suffer larger infarctions, reduced functional recovery and increased BBB disruption preceding observable neuronal injury.