Department of Neurology, Nanfang Hospital, Southern Medical Univerisity, North Avenue 1838#, Guangzhou, Guangzhou, 510515, China.
Department of Dermatology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China.
J Neuroinflammation. 2020 Jul 23;17(1):219. doi: 10.1186/s12974-020-01879-1.
Brain injury is the leading cause of death and disability in survivors of cardiac arrest, where neuroinflammation is believed to play a pivotal role, but the underlying mechanism remains unclear. Pyroptosis is a pro-inflammatory form of programmed cell death that triggers inflammatory response upon infection or other stimuli. This study aims to understand the role of microglial pyroptosis in post-cardiac arrest brain injury.
Sprague-Dawley male rats underwent 10-min asphyxial cardiac arrest and cardiopulmonary resuscitation or sham-operation. Flow cytometry analysis, Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), co-immunoprecipitation, and immunofluorescence were used to evaluate activated microglia and CD11b-positive leukocytes after cardiac arrest and assess inflammasome activation and pyroptosis of specific cellular populations. To further explore the underlying mechanism, MCC950 or Ac-YVAD-cmk was administered to block nod-like receptor family protein 3 (NLRP3) or caspase-1, respectively.
Our results showed that, in a rat model, successful resuscitation from cardiac arrest resulted in microglial pyroptosis and consequential inflammatory infiltration which was mediated by the activation of NLRP3 inflammasome. Targeting NLRP3 and caspase-1, the executor of pyroptosis, with selective inhibitors MCC950 and Ac-YVAD-cmk treatment significantly prevented microglial pyroptosis, reduced infiltration of leukocytes, improved neurologic outcome, and alleviated neuro-pathological damages after cardiac arrest in modeling rats.
This study demonstrates that microglial pyroptosis mediated by NLRP3 inflammasome is critically involved in the pathogenesis of post-cardiac arrest brain injury and provides a new therapeutic strategy.
脑损伤是心脏骤停幸存者死亡和残疾的主要原因，其中神经炎症被认为起着关键作用，但潜在机制尚不清楚。细胞焦亡是一种炎症形式的程序性细胞死亡，在感染或其他刺激下会引发炎症反应。本研究旨在了解小胶质细胞细胞焦亡在心脏骤停后脑损伤中的作用。
雄性 Sprague-Dawley 大鼠行 10 分钟窒息性心脏骤停和心肺复苏或假手术。流式细胞术分析、Western blot、实时定量聚合酶链反应（qRT-PCR）、共免疫沉淀和免疫荧光用于评估心脏骤停后活化的小胶质细胞和 CD11b 阳性白细胞，并评估炎性小体激活和特定细胞群的细胞焦亡。为了进一步探讨潜在机制，分别用 MCC950 或 Ac-YVAD-cmk 阻断核苷酸结合寡聚化结构域样受体家族蛋白 3（NLRP3）或半胱天冬酶-1。
我们的结果表明，在大鼠模型中，心脏骤停后的成功复苏导致小胶质细胞细胞焦亡和随之而来的炎症浸润，这是由 NLRP3 炎性小体的激活介导的。用选择性抑制剂 MCC950 和 Ac-YVAD-cmk 靶向 NLRP3 和细胞焦亡的执行者半胱天冬酶-1，可显著预防小胶质细胞细胞焦亡，减少白细胞浸润，改善心脏骤停后建模大鼠的神经功能预后，并减轻神经病理损伤。
本研究表明，NLRP3 炎性小体介导的小胶质细胞细胞焦亡在心脏骤停后脑损伤的发病机制中起着关键作用，并为该疾病提供了新的治疗策略。
