Echinatin alleviates inflammation and pyroptosis in hypoxic-ischemic brain damage by inhibiting TLR4/ NF-?B pathway

Hypoxic ischemic encephalopathy (HIE) is a primary cause of neonatal death and disabilities resulting from perinatal hypoxia. The progression of HI injury is closely associated with neuroinflammation. Therefore, suppressing inflammatory pathways is a promising therapeutic strategy for treating HIE. Echinatin (Ech) is a principal active component of glycyrrhiza, with anti-inflammatory and anti-oxidative effects, often combined with other herbs to exert effects of clearing heat and detoxifying. This study aimed to investigate the anti-inflammatory and neuroprotective effects of Ech on neonatal rats with hypoxic-ischemic brain damage and on PC12 cells induced by oxygen-glucose deprivation (OGD). Overall design: Seven-day-old SD rats were subjected to 2.5 hours of ischemia-hypoxia for transcriptome sequencing. The results showed that inflammatory genes were enriched in HI rats compared with normal rats, the results were verified by PCR and wb, and TLR4, MyD88 and NF-?B were identified as the key regulators.. In vitro, Ech reduced TLR4-related protein levels, inhibited nuclear translocation of NF-?B, reduced the expression of downstream inflammatory cytokines, and prevented pyroptosis and cell membrane destruction. These results suggest that Ech can reduce neuroinflammation and pyroptosis in HI injury by inhibiting the TLR4/NF-?B pathway, which is expected to be a potential candidate for the treatment of HIE.

缺氧缺血性脑病（hypoxic ischemic encephalopathy, HIE）是围产期缺氧引发新生儿死亡与残疾的主要病因。缺氧缺血性损伤的进展与神经炎症密切相关，因此抑制炎症通路是治疗HIE的极具前景的治疗策略。甘草素（Echinatin, Ech）是甘草的主要活性成分之一，具备抗炎与抗氧化活性，常与其他药材配伍以发挥清热解毒之效。本研究旨在探究Ech对缺氧缺血性脑损伤新生大鼠，以及氧糖剥夺（oxygen-glucose deprivation, OGD）诱导的PC12细胞的抗炎与神经保护作用。
整体实验设计：选取7日龄SD大鼠，给予2.5小时缺血缺氧处理后开展转录组测序。结果显示，相较于正常大鼠，缺氧缺血模型大鼠体内炎症基因显著富集；该结果通过聚合酶链式反应（PCR）与蛋白质免疫印迹（Western Blot, WB）验证，并确定TLR4、MyD88及核因子κB（NF-κB）为关键调控因子。体外实验中，Ech可降低TLR4相关蛋白表达水平，抑制NF-κB的核转位，减少下游炎症细胞因子的表达，并阻断细胞焦亡（pyroptosis）与细胞膜破坏。上述结果表明，Ech可通过抑制TLR4/NF-κB通路，减轻缺氧缺血损伤中的神经炎症与细胞焦亡，有望成为治疗HIE的潜在候选药物。