Partially purified components of Uncaria sinensis attenuate blood brain barrier disruption after ischemic brain injury in mice

BACKGROUND Uncaria sinensis (US) has long been used in traditional Korean medicine to relieve various nervous-related symptoms and cardiovascular disease. We recently showed the neuroprotective and cerebrovascular protective effects of US on cerebral ischemia; however, its effects on the blood-brain barrier (BBB) are poorly understood. In this study, the effects of partially purified components of US (PPUS) on BBB disruption were investigated in mice subjected to ischemic brain injury. METHODS Focal cerebral ischemia was induced in C57BL/6J mice by photothrombotic cortical ischemia. PPUS was injected intraperitoneally 30 min before ischemic insults. Infarct volume, neurological score, wire-grip test, Evans blue leakage and brain water content were then examined 24 h after ischemic brain injury. RESULTS Infarct volume was significantly reduced and neurological deficit and motor deficit were greatly improved in PPUS-pretreated mice relative to those treated with vehicle following photothrombotic cortical ischemia. Brain edema-induced change of Evans blue extravasation and water content in the ipsilateral hemisphere were alleviated by treatment with PPUS. In addition, PPUS significantly reduced ischemic brain injury-induced degradation of tight junction proteins and elevation of matrix metalloproteinase-9 (MMP-9). CONCLUSIONS PPUS prevents cerebral ischemic damage by BBB protection, and these effects were associated with inhibition of tight junction degradation and MMP-9 induction.