Department of Neurosurgery & Neurocritical Care, Huashan Hospital Affiliated to Fudan University, Shanghai, 200040, China.
Department of Neurology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, 200092, China.
Inflammation. 2021 Jun;44(3):934-945. doi: 10.1007/s10753-020-01388-6. Epub 2021 Jan 7.
Endoplasmic reticulum stress is an important contributor to the cerebral ischemic injury. Sappanone A (SA), a kind of natural homoisoflavanone extracted from Caesalpinia sappan L, has been evidenced to exhibit anti-inflammatory and antioxidative properties. The present study aimed to investigate the potential neuroprotective effects of SA in cerebral ischemia-reperfusion injury. The potential neuroprotective effect of SA was tested in a rat model of middle cerebral artery occlusion (MCAO) allowing reperfusion and PC12 cell model of oxygen-glucose deprivation and reperfusion (OGD/R). Post-ischemic neuronal injury was evaluated by 2, 3, 5-triphenyltetrazolium chloride (TTC) and hematoxylin-eosin (H&E) staining. The levels of inflammatory factors and oxidative stress-related markers were detected using corresponding kits. Cell apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) or flow cytometry, and the expression of apoptosis-associated proteins was determined using western blot analysis. Subsequently, endoplasmic reticulum stress-related proteins were detected through western blot analysis, and CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP) was overexpressed to confirm the contribution of endoplasmic reticulum stress inhibition by SA to the neuroprotective effects post OGD/R. Results revealed that SA was effective in ameliorating cerebral infarction and pathological injuries post-reperfusion following MCAO, which is associated with reduced inflammation, oxidative stress, and cell apoptosis by SA in the brain. Consistently, these neuroprotective effects of SA post ischemia-reperfusion were also observed in a PC12 cell model of OGD/R. Importantly, endoplasmic reticulum stressors, including the CHOP, the 78 kDa glucose-regulated protein 78 (GRP78), and phosphorylated eukaryotic initiation factors 2α (EIF-2α), were significantly downregulated by SA, while CHOP overexpression attenuated the beneficial effects of SA on inflammation, oxidative stress, and apoptosis in OGD/R-induced PC12 cells. These results demonstrated that SA alleviates endoplasmic reticulum stress, ameliorating inflammation, oxidative stress, and apoptosis, and thereby serves as therapeutic potential for protection against cerebral ischemia-reperfusion injury in ischemic stroke.
内质网应激是脑缺血损伤的一个重要因素。紫檀芪 A（SA）是从苏木中提取的一种天然异黄酮，已被证明具有抗炎和抗氧化作用。本研究旨在探讨 SA 对脑缺血再灌注损伤的潜在神经保护作用。在大脑中动脉闭塞（MCAO）再灌注的大鼠模型和氧葡萄糖剥夺和再灌注（OGD/R）的 PC12 细胞模型中测试了 SA 的潜在神经保护作用。通过 2,3,5-三苯基氯化四氮唑（TTC）和苏木精-伊红（H&E）染色评估缺血后神经元损伤。使用相应的试剂盒检测炎症因子和氧化应激相关标志物的水平。通过末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）或流式细胞术评估细胞凋亡，通过 Western blot 分析测定凋亡相关蛋白的表达。随后，通过 Western blot 分析检测内质网应激相关蛋白，并过表达 CCAAT/增强子结合蛋白（C/EBP）同源蛋白（CHOP），以确认 SA 对 OGD/R 后神经保护作用的内质网应激抑制作用。结果表明，SA 可有效改善 MCAO 再灌注后大脑中的脑梗死和病理损伤，这与 SA 减轻脑内炎症、氧化应激和细胞凋亡有关。一致地，SA 在缺血再灌注后的 PC12 细胞 OGD/R 模型中也观察到了这些神经保护作用。重要的是，内质网应激物，包括 CHOP、78 kDa 葡萄糖调节蛋白 78（GRP78）和磷酸化真核起始因子 2α（EIF-2α），被 SA 显著下调，而 CHOP 过表达减弱了 SA 对 OGD/R 诱导的 PC12 细胞中炎症、氧化应激和凋亡的有益作用。这些结果表明，SA 减轻内质网应激，改善炎症、氧化应激和凋亡，从而为缺血性中风的脑缺血再灌注损伤提供治疗潜力。
