Objective: DL-3n-butylphthalide (NBP) has beneficial effects in different stages of ischemic stroke. Our previous studies have demonstrated that NBP promoted angiogenesis in the perifocal region of the ischemic brain. However, the molecular mechanism of NBP for blood–brain barrier protection in acute ischemic stroke was unclear. Here, we explored the neuroprotective effects of NBP on blood–brain barrier integrity in the acute phase of ischemic stroke in a rat model.

Methods: Adult male Sprague–Dawley rats (n = 82) underwent 2 h of transient middle cerebral artery occlusion and received 90 mg/kg of NBP for 3 days. Brain edema, infarct volume, surface blood flow, and neurological severity score were evaluated. Blood–brain barrier integrity was evaluated by Evans blue leakage and changes in tight junction proteins. We further examined AQP4 and eNOS expression, MMP-9 enzyme activity, and possible signaling pathways for the role of NBP after ischemic stroke.

Results: NBP treatment significantly increased eNOS expression and surface blood flow in the brain, reduced brain edema and infarct volume, and improved neurological severity score compared to the control group (p < 0.05). Furthermore, NBP attenuated Evans blue and IgG leakage and increased tight junction protein expression compared to the control after 1 and 3 days of ischemic stroke (p < 0.05). Finally, NBP decreased AQP4 expression, MMP-9 enzyme activity, and increased MAPK expression during acute ischemic stroke.

Conclusion: NBP protected blood–brain barrier integrity and attenuated brain injury in the acute phase of ischemic stroke by decreasing AQP4 expression and MMP-9 enzyme activity. The MAPK signaling pathway may be associated in this process.

目的：DL-3n-丁基邻苯二甲酸酯（NBP）在缺血性卒中的不同阶段均具有有益的作用。我们以前的研究表明，NBP促进了缺血性脑的局灶性区域的血管生成。然而，NBP在急性缺血性中风中保护血脑屏障的分子机制尚不清楚。在这里，我们探讨了NBP对大鼠缺血性脑卒中急性期血脑屏障完整性的神经保护作用。

方法： 成年雄性Sprague–Dawley大鼠（ñ= 82）进行了2 h短暂性脑中动脉闭塞，并接受90 mg / kg NBP，持续3天。评估脑水肿，梗塞体积，表面血流量和神经系统严重程度评分。血脑屏障的完整性通过埃文斯蓝漏失和紧密连接蛋白的变化进行了评估。我们进一步检查了缺血性卒中后AQP4和eNOS的表达，MMP-9酶的活性以及NBP作用的可能信号通路。

结果： 与对照组相比，NBP治疗显着增加了脑中eNOS的表达和表面血流量，减少了脑水肿和梗塞体积，并改善了神经系统严重程度评分（p<0.05）。此外，与对照组相比，缺血性卒中1天和3天后，NBP减轻了Evans蓝和IgG渗漏，并增加了紧密连接蛋白的表达（p<0.05）。最后，在急性缺血性中风期间，NBP降低了AQP4表达，MMP-9酶活性并增加了MAPK表达。

结论：NBP通过降低AQP4表达和MMP-9酶活性来保护缺血性中风急性期的血脑屏障完整性并减轻脑损伤。MAPK信号通路可能与此过程相关。