Lentivirus-mediated transfer of MMP-9 shRNA provides neuroprotection following focal ischemic brain injury in rats

Various studies on focal cerebral ischemic models have implicated the direct activation and expression of matrix metalloproteinases (MMPs), especially MMP-9, as a key orchestrator of blood-brain barrier (BBB) disruption. Moreover, studies have shown that MMP-9 siRNA can protect the BBB from ischemia/reperfusion injury. In the present study, we investigated the neuroprotective role of a lentivirus vector-mediated mmp-9shRNA following focal cerebral ischemia specifically assessing whether LV-mmp9shRNA silencing of MMP-9 mRNA could ameliorate BBB disruption and in turn reduce vascular permeability, neuronal cell death, and neurobehavioral deficits. Treatment was given 2 weeks prior to surgery using a lentivirus-mediated vector. Surgery was conducted using the established middle cerebral artery occlusion (MCAO) model in rats, while outcomes were measured 24 h after injury. Our results demonstrated a significant reduction in brain infarction volume, brain water content, and neurobehavioral deficits following LV-mmp9shRNA treatment. Additionally, Evans blue and IgG extravasation were reduced, MMP-9 mRNA expression was silenced, and Western blot analysis revealed a decreased expression of MMP-9 and VEGF with an increased expression of occludin and collagen IV in brain tissues. This suggests that successful delivery of LV-mmp9shRNA may ameliorate ischemic brain injury by preserving structural integrity and improving functional outcome. (C) 2010 Elsevier B.V. All rights reserved.