Chelluboina Bharath, Klopfenstein Jeffrey D, Pinson David M, Wang David Z, Vemuganti Raghu, Veeravalli Krishna Kumar
From the Departments of Cancer Biology and Pharmacology (B.C., K.K.V.), Neurosurgery (J.D.K.), Pathology (D.M.P.), and Neurology (D.Z.W.), University of Illinois College of Medicine at Peoria; Department of Neurological Surgery, School of Medicine and Public Health, University of Wisconsin, Madison (R.V.); and Comprehensive Stroke Center, Illinois Neurological Institute, Peoria (J.D.K., D.Z.W.).
Stroke. 2015 Dec;46(12):3523-31. doi: 10.1161/STROKEAHA.115.011031. Epub 2015 Nov 3.
Matrix metalloproteinases (MMPs) have a central role in compromising the integrity of the blood-brain barrier (BBB). The role of MMP-12 in brain damage after ischemic stroke remains unknown. The main objective of the current study is to investigate the effect of MMP-12 suppression at an early time point before reperfusion on the BBB damage in rats.
Sprague-Dawley rats were subjected to middle cerebral artery occlusion and reperfusion. MMP-12 shRNA-expressing plasmids formulated as nanoparticles were administered at a dose of 1 mg/kg body weight. The involvement of MMP-12 on BBB damage was assessed by performing various techniques, including Evans blue dye extravasation, 2,3,5-triphenyltetrazolium chloride staining, immunoblot, gelatin zymography, and immunofluorescence analysis.
MMP-12 is upregulated ≈31-, 47-, and 66-fold in rats subjected 1-, 2-, or 4-hour ischemia, respectively, followed by 1-day reperfusion. MMP-12 suppression protected the BBB integrity by inhibiting the degradation of tight-junction proteins. Either intravenous or intra-arterial delivery of MMP-12 shRNA-expressing plasmid significantly reduced the percent Evans blue dye extravasation and infarct size. Furthermore, MMP-12 suppression reduced the endogenous levels of other proteases, such as tissue-type plasminogen activator and MMP-9, which are also known to be the key players involved in BBB damage.
These results demonstrate the adverse role of MMP-12 in acute brain damage that occurs after ischemic stroke and, thereby, suggesting that MMP-12 suppression could be a promising therapeutic target for cerebral ischemia.
基质金属蛋白酶（MMPs）在破坏血脑屏障（BBB）完整性方面起着核心作用。MMP-12在缺血性中风后脑损伤中的作用尚不清楚。本研究的主要目的是探讨在再灌注前的早期时间点抑制MMP-12对大鼠血脑屏障损伤的影响。
对Sprague-Dawley大鼠进行大脑中动脉闭塞和再灌注。以纳米颗粒形式配制的表达MMP-12 shRNA的质粒以1 mg/kg体重的剂量给药。通过进行各种技术评估MMP-12对血脑屏障损伤的影响，包括伊文思蓝染料外渗、2,3,5-三苯基四氮唑氯化物染色、免疫印迹、明胶酶谱分析和免疫荧光分析。
在分别经历1小时、2小时或4小时缺血并随后进行1天再灌注的大鼠中，MMP-12分别上调约31倍、47倍和66倍。抑制MMP-12通过抑制紧密连接蛋白的降解来保护血脑屏障的完整性。静脉内或动脉内递送表达MMP-12 shRNA的质粒均显著降低了伊文思蓝染料外渗百分比和梗死面积。此外，抑制MMP-12降低了其他蛋白酶的内源性水平，如组织型纤溶酶原激活剂和MMP-9，它们也被认为是参与血脑屏障损伤的关键因素。
这些结果证明了MMP-12在缺血性中风后发生的急性脑损伤中的不良作用，从而表明抑制MMP-12可能是治疗脑缺血的一个有前景的治疗靶点。
