Evaluation of the therapeutic effects of nicotinamide adenine dinucleotide phosphate oxidase inhibition in a rodent model of transient ischaemic stroke

Background: Ischaemic stroke, a leading cause of mortality and disability, induces oxidative stress (OS), largely driven by overactive nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Targeting this enzyme system may offer therapeutic benefits by mitigating cerebrovascular damage. Aim: This study investigated whether suppressing NADPH oxidase through VAS2870 reduces ischaemic brain injury and functional deficits in a rodent stroke model. Methods: Male Sprague Dawley rats underwent 45-min middle cerebral artery occlusion (MCAO), followed by intravenous VAS2870 or vehicle administration 30 min post-reperfusion. Infarct volume was measured at 48 h and day 11 post-MCAO using magnetic resonance imaging or Nissl staining. At day 11 post-MCAO, brains and blood samples were collected to analyse OS, inflammation and cellular changes. Behavioural tests were used to evaluate cognitive and functional outcomes. Results: VAS2870 significantly improved survival outcome following MCAO. However, no significant differences in infarct volume were observed between the control and VAS2870-treated groups. In addition, no significant alterations were detected in total antioxidant capacity, interleukin-1 beta, tissue inhibitor of metalloproteinases-1, or vascular endothelial growth factor levels. Assessment of post-MCAO functional and cognitive deficits revealed a significant worsening of neurological function following VAS2870 treatment on day 2, whereas no significant effect of NADPH oxidase inhibition was found at day 11 post-MCAO. In addition, cellular analysis showed no effect of NADPH oxidase inhibition on neuronal counts, neurogenesis, or angiogenesis in MCAO-affected brain regions. Conclusion: Although post-MCAO targeting of NADPH oxidase significantly improved acute survival, it did not significantly reduce ischaemic injury or improve functional outcome. These findings suggest that although NADPH oxidase inhibition holds promise as a therapeutic strategy, its effectiveness may be limited, particularly when administered during early phases of cerebral reperfusion. Relevance for patients: Although inhibition of NADPH oxidase alone did not improve cognition and neurovascular recovery, it may be beneficial in post-stroke recanalisation therapy.