DL-3-n-butylphthalide protects the blood-brain barrier against ischemia/hypoxia injury via upregulation of tight junction proteins

Abstract

Background: The increased permeability of the blood-brain barrier (BBB) induced by ischemia/hypoxia is generally correlated with alteration of tight junctions (TJs). DL-3-n-butylphthalide (NBP) has been shown to exert neuroprotective effects after ischemic injury. However, few studies have assessed the correlation between NBP and TJs. This study aimed to investigate the potential effect of NBP on the TJ proteins claudin-5, zonula occludens-1 (ZO-1), and occludin during brain ischemia. Methods: A chronic cerebral hypoperfusion (CCH) Sprague-Dawley rat model was established, and NBP (20, 40, or 80 mg/kg, gavage, once a day) treatment was performed for 14 days. NBP (0.1 or 1.0 μmol/L) pre-treatment was applied to an in vitro hypoxia microvascular endothelial cell model (1% O 2 , 24 h). BBB permeability was assessed by performing the Evans blue assay. The expressions and localization of claudin-5, ZO-1, occludin, phosphorylated/total protein kinase B (p-Akt/Akt), phosphorylated/total glycogen synthase kinase 3β (GSK-3β)/GSK-3β, and β-catenin/β-actin were evaluated by Western blotting or immunofluorescence. Reactive oxygen species (ROS) generation was measured by flow cytometry analysis. TJ ultrastructure was observed by transmission electron microscopy. Results: In CCH rats, treatment with 40 and 80 mg/kg NBP decreased the Evans blue content in brain tissue (9.0 ± 0.9 μg/g vs. 12.3 ± 1.9 μg/g, P = 0.005; 6.7 ± 0.6 μg/g vs. 12.3 ± 1.9 μg/g, P < 0.01), increased the expression of claudin-5 (0.79 ± 0.08 vs. 0.41 ± 0.06, P < 0.01; 0.97 ± 0.07 vs. 0.41 ± 0.06, P < 0.01), and elevated the ZO-1 protein level ( P < 0.05) in brain microvascular segments in a dose-dependent manner in comparison with the corresponding values in the model group. There was no significant difference in occludin expression ( P > 0.05). In the hypoxia cell model, NBP pre-treatment improved TJ ultrastructure, decreased intracellular ROS level, and increased the expression of claudin-5 ( P < 0.01) and ZO-1 ( P < 0.01) in comparison with the corresponding values in the hypoxia group. NBP treatment also elevated the relative expression levels of p-Akt/Akt, p-GSK-3β/GSK-3β, and β-catenin/β-actin in comparison with the corresponding values in the hypoxia group (all P < 0.05). Conclusion: NBP improves the barrier function of BBB against ischemic injury by upregulating the expression of TJ proteins, possibly by reducing oxidative stress and activating the Akt/GSK-3β/β-catenin signaling pathway.

Dl-NBP (Dl-3-N-Butylphthalide) Treatment Promotes Neurological Functional Recovery Accompanied by the Upregulation of White Matter Integrity and HIF-1α/VEGF/Notch/Dll4 Expression

“…Disruption of BBB integrity is one of the key factors in the pathological damage of white matter hyperintensities burden . This result suggests that dl-NBP may increase the integrity of white matter through increasing the integrity of the BBB via upregulating the expression of tight junction proteins, which is consist with a previous study showing that NBP reduced ischemia-induced BBB damage via upregulation of tight junction proteins (Ye et al, 2019).…”

“…BBB integrity is important for functional recovery after ischemic stroke and dl-NBP has been demonstrated to alleviate ischemia-induced blood-brain barrier (BBB) damage via promoting the expression of tight junction proteins (Ye et al, 2019). Here, we checked the effect of dl-NBP on the expression of the tight junction protein occludin.…”

Melodinhenine B attenuates NLRP3 expression in a cerebral ischemia/reperfusion-induced neuronal injury rat model

“…es in the integrity of the BBB [9]. Tight junction proteins have a role in neuronal injury, and the expression of ZO-1 and occluding proteins protects against neuronal injury [23]. We found that treatment with melodinhenine B normalized the altered expression of ZO-1 and occluding proteins in the cerebral tissues of I/R-induced neuronal injury rats.…”

Total Glycosides of Cistanche deserticola Promote Neurological Function Recovery by Inducing Neurovascular Regeneration via Nrf-2/Keap-1 Pathway in MCAO/R Rats

“…Imaging research into stroke patients showed that BBB dysfunction can be thought as a striking attribute of the periischemic brain (Bang et al, 2007). The TJs, which are composed of cytoplasmic proteins, transmembrane proteins, and junction adhesion molecules between capillary endothelial cells, are very important in maintaining BBB integrity (Ye et al, 2019). Among them, ZO-1, claudin-5, and occludin are the most important proteins in TJs.…”