Neuroinflammation-related amyloid-beta peptide (Aβ) accumulation after cerebral ischemia/reperfusion (I/R) accounts for cerebral I/R injuries and poststroke dementia. Recently, pyroptosis, a proinflammatory cell death, has been identified as a crucial pathological link of cerebral I/R injuries. However, whether pyroptosis acts as a trigger of Aβ accumulation after cerebral I/R has not yet been demonstrated. Blood-brain barrier (BBB) and glymphatic system mediated by aquaporin-4 (AQP-4) on astrocytic endfeet are important pathways for the clearance of Aβ in the brain, and pyroptosis especially occurring in astrocytes after cerebral I/R potentially damages BBB integrity and glymphatic function and thus influences Aβ clearance and brain homeostasis. In present study, the method of middle cerebral artery occlusion/reperfusion (MCAO/R) was used for building models of focal cerebral I/R injuries in rats. Then, we used lipopolysaccharide and glycine as the agonist and inhibitor of pyroptosis, respectively, Western blotting for detections of pyroptosis, AQP-4, and Aβ_1-42 oligomers, laser confocal microscopy for observations of pyroptosis and Aβ locations, and immunohistochemical stainings of SMI 71 (a specific marker for BBB integrity)/AQP-4 and Nissl staining for evaluating, respectively, BBB-glymphatic system and neuronal damage. The results showed that pyroptosis obviously promoted the loss of BBB integrity and AQP-4 polarization, brain edema, Aβ accumulation, and the formation of Aβ_1-42 oligomers and thus increased neuronal damage after cerebral I/R. However, glycine could inhibit cerebral I/R-induced pyroptosis by alleviating cytomembrane damage and downregulating expression levels of cleaved caspase-11/1, N-terminal gasdermin D, NLRP3 (nucleotide-binding domain, leucine-rich repeat containing protein 3), interleukin-6 (IL-6) and IL-1β and markedly abate above pathological changes. Our study revealed that pyroptosis is a considerable factor causing toxic Aβ accumulation, dysfunctional BBB-glymphatic system, and neurological deficits after cerebral I/R, suggesting that targeting pyroptosis is a potential strategy for the prevention of ischemic stroke sequelae including dementia.

中文翻译：

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Pyroptosis 对大鼠脑缺血/再灌注后与功能失调的 BBB-Glymphatic 系统和β-淀粉样蛋白积累相关的神经元存活稳态的破坏性影响

神经炎症相关的淀粉样蛋白β肽（A β）的积累后脑缺血/再灌注（I / R）占脑I / R损伤和中风后痴呆。最近，细胞焦亡（一种促炎性细胞死亡）已被确定为脑 I/R 损伤的关键病理环节。然而，尚未证实在脑 I/R 后细胞焦亡是否是 A β积累的触发因素。血脑屏障 (BBB) 和由水通道蛋白 4 (AQP-4) 介导的星形胶质细胞末端的淋巴系统是清除脑内A β 的重要途径，尤其是脑 I/R 后星形胶质细胞发生焦亡可能会损害 BBB完整性和淋巴功能，从而影响 A β清除和大脑稳态。本研究采用大脑中动脉闭塞/再灌注（MCAO/R）方法建立大鼠局灶性脑I/R损伤模型。然后，我们分别使用脂多糖和甘氨酸作为细胞焦亡的激动剂和抑制剂，Western blotting 检测细胞焦亡、AQP-4 和 A β _1-42寡聚体，激光共聚焦显微镜观察细胞焦亡和 A β位置，免疫组化SMI 71（BBB 完整性的特异性标志物）/AQP-4 和 Nissl 染色分别用于评估 BBB 淋巴系统和神经元损伤。结果表明，细胞焦亡明显促进了 BBB 完整性的丧失和 AQP-4 极化、脑水肿、Aβ积累，并形成 A β _1-42寡聚体，从而增加脑 I/R 后的神经元损伤。然而，甘氨酸可以通过减轻细胞膜损伤和下调 cleaved caspase-11/1、N 末端 gasdermin D、NLRP3（核苷酸结合域，富含亮氨酸重复蛋白 3）的表达水平来抑制脑 I/R 诱导的细胞焦亡，白细胞介素6（IL-6）和IL- 1β和上述病理变化明显减弱。我们的研究表明，细胞焦亡是导致毒性 A β积累、功能失调的 BBB-glymphatic 系统和脑 I/R 后神经功能缺损的重要因素，这表明靶向焦亡是预防包括痴呆在内的缺血性中风后遗症的潜在策略。