Department of Geriatrics, the First Affiliated Hospital of Hebei North University, Zhangjiakou 075000, Hebei, China.
Department of Pharmacy, Hospital of Luzhong Mining Co., Ltd., Laiwu 271113, Shandong, China.
Eur J Pharmacol. 2019 Jun 15;853:210-219. doi: 10.1016/j.ejphar.2019.03.015. Epub 2019 Mar 12.
Brain endothelial permeability plays a crucial role in blood-brain barrier (BBB), but the permeability enhancement in cerebral ischemia reperfusion (I/R). Vitexin has certain neuroprotective effects, but the effect brain endothelial permeability in I/R injury was unknown. In this study, the effects of Vitexin on endothelial permeability and the underlying mechanisms in human brain microvascular endothelial cells (HBMEc) I/R injury model were investigated. Cell viability, lactate dehydrogenase (LDH), inflammation and apoptosis were detected. The effects of Vitexin on BBB integrity tight junction, matrix metalloproteinases (MMP) were also investigated. The mechanism was confirmed by PI3K inhibitor and NOS inhibitor in normal or eNOS siRNA transfection HBMEc. Vitexin significantly reduced LDH, Caspase 3 level, alleviated inflammation, also could maintain BBB integrity, increased tight junction proteins expression and inhibited MMP. The mechanism is related to reduction of intracellular NO and ONOO, regulated eNOS, iNOS activity. Vitexin significantly preserved eNOS phosphorylation in response to the activated Akt. Moreover, combined with PI3K inhibitor or low dosage of NOS inhibitor, totally abolished Vitexin-induced eNOS phosphorylation, the protected effect was also attenuated, but still significantly between model cells. However, combined with high dosage NOS inhibitor which both inhibited the eNOS phosphorylation and iNOS, the protected effect of Vitexin was abrogated. In addition, eNOS silencing cells were used to further clarify the regulatory role of Vitexin on iNOS. Our findings showed that Vitexin could play a protective role in I/R-induced brain endothelial permeability by simultaneously increase eNOS phosphorylation and inhibit iNOS.
脑内皮细胞通透性在血脑屏障（BBB）中起着至关重要的作用，但在脑缺血再灌注（I/R）中通透性会增强。牡荆素具有一定的神经保护作用，但它对 I/R 损伤中脑内皮细胞通透性的影响尚不清楚。在这项研究中，研究了牡荆素对人脑血管内皮细胞（HBMEc）I/R 损伤模型中内皮通透性的影响及其潜在机制。检测了细胞活力、乳酸脱氢酶（LDH）、炎症和细胞凋亡。还研究了牡荆素对 BBB 完整性紧密连接、基质金属蛋白酶（MMP）的影响。通过在正常或 eNOS siRNA 转染的 HBMEc 中使用 PI3K 抑制剂和 NOS 抑制剂来证实该机制。牡荆素显著降低了 LDH、Caspase 3 水平，减轻了炎症反应，还能维持 BBB 的完整性，增加紧密连接蛋白的表达并抑制 MMP。其机制与减少细胞内 NO 和 ONOO、调节 eNOS、iNOS 活性有关。牡荆素还能显著保留 eNOS 磷酸化，以响应 Akt 的激活。此外，与 PI3K 抑制剂或低剂量 NOS 抑制剂联合使用，完全消除了牡荆素诱导的 eNOS 磷酸化，保护作用也减弱，但与模型细胞相比仍有显著差异。然而，与同时抑制 eNOS 磷酸化和 iNOS 的高剂量 NOS 抑制剂联合使用时，牡荆素的保护作用被消除。此外，还使用 eNOS 沉默细胞进一步阐明了牡荆素对 iNOS 的调节作用。研究结果表明，牡荆素可通过同时增加 eNOS 磷酸化和抑制 iNOS 来发挥对 I/R 诱导的脑内皮细胞通透性的保护作用。
