Rosmarinic acid attenuates blood-brain barrier dysfunction to improve cerebral ischemia/reperfusion injury in mice.

BACKGROUND

Cerebral ischemia/reperfusion (CI/R) has detrimental effects in cases of ischemic stroke. This notably triggers the blood-brain-barrier (BBB) to break. Known for its ability to provide neuroprotective benefits, rosmarinic acid (RosA) is a phenolic acid compound in the Lamiaceae family of plants. However, the relevance between the neuroprotective effect of RosA on CI/R and its direct protective effect on the BBB remains unclear. This study aimed to investigate how RosA regulates BBB integrity after CI/R injury and explore its underlying pharmacological mechanism in mice.

METHODS

The mouse model of middle cerebral artery occlusion (MCAO) was established by subjecting the animals to 1 h of ischemia followed by a 24-h reperfusion period. Neurological scoring, infarct size, BBB permeability, histological examination, and biochemical parameters were subsequently assessed.

RESULTS

Our study showed that RosA improved neurofunction and reduced infarct size by protecting BBB permeability, alleviating CI/R-induced neuronal loss and apoptosis. Molecular docking, molecular dynamics (MD) simulationand surface plasmon resonance (SPR) suggested that RosA may directly bind to matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2). Furthermore, RosA significantly enhanced tight junction proteins, including zonula occludens-1 (ZO-1), occludin and claudin 5, while simultaneously decreasing the levels of MMP-9 and MMP-2 mRNA and proteins.

CONCLUSION

Our findings reveal that RosA significantly mitigates CI/R-induced BBB disruption in middle cerebral artery occlusion (MCAO) mice by enhancing tight junction protein expression and down-regulating MMP-9 and MMP-2 levels.