虾青素通过调节 ATP-P2X7R 信号减轻癫痫持续状态大鼠的神经炎症。

Astaxanthin Attenuates Neuroinflammation in Status Epilepticus Rats by Regulating the ATP-P2X7R Signal.

机构信息

Department of Neurology, Jinshan Hospital, Fudan University, Shanghai, People's Republic of China.

Department of Neurology, Huashan Hospital North, Fudan University, Shanghai, People's Republic of China.

出版信息

Drug Des Devel Ther. 2020 Apr 30;14:1651-1662. doi: 10.2147/DDDT.S249162. eCollection 2020.

BACKGROUND

As a life-threatening neurological emergency, status epilepticus (SE) is often refractory to available treatment. Current studies have shown a causal role of neuroinflammation in patients with lower seizure thresholds and driving seizures. The ATP-gated purinergic P2X7 receptor (P2X7R) is mainly expressed on the microglia, which function as gatekeepers of inflammation. Although emerging evidence has demonstrated significant anti-inflammatory effects of astaxanthin (AST) in SE, the associated mechanism remains unclear. Therefore, this study aimed to clarify the effects of AST on P2X7R-related inflammation in SE.

METHODS

SE was induced in rats using lithium-pilocarpine, and AST was administered 1 h after SE induction. Rat microglia were treated with lipopolysaccharide (LPS), AST, ATP, 2,3-O-4-benzoyl-4-benzoyl-ATP (BzATP) and oxidized ATP (oxATP). The Morris water maze, immunohistochemistry, and Nissl staining were performed in rats. Expressions of P2X7R and inflammatory cytokines (such as cycloxygenase-2 (Cox-2), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α)) were detected using real-time polymerase chain reaction (RT-PCR) and Western blot (WB) both in rats and microglia. ATP concentration in the microglia was evaluated using ELISA.

RESULTS

The AST alleviated hippocampal injury and improved cognitive dysfunction induced by SE. AST also effectively inhibited inflammation and downregulated P2X7R expression in both rat brain and microglia. The results also showed that AST reduced the extracellular ATP levels and that P2X7R expression could be increased by extracellular ATP. In addition, BzATP upregulates the expression of P2X7R and inflammatory factors in microglia. Conversely, it downregulates the expression of P2X7R and inflammatory factors.

CONCLUSION

Our study suggests that AST attenuated ATP-P2X7R mediated inflammation in SE.

背景

癫痫持续状态（Status Epilepticus，SE）作为一种危及生命的神经系统急症，常对现有治疗方法产生抵抗。目前的研究表明，神经炎症在具有较低发作阈值和驱动发作的患者中起着因果作用。三磷酸腺苷门控嘌呤能 P2X7 受体（P2X7 Receptor，P2X7R）主要表达在小胶质细胞上，小胶质细胞作为炎症的“守门员”。尽管越来越多的证据表明虾青素（Astaxanthin，AST）在 SE 中具有显著的抗炎作用，但相关机制尚不清楚。因此，本研究旨在阐明 AST 对 SE 中 P2X7R 相关炎症的影响。

方法

采用锂-匹罗卡品诱导 SE 大鼠模型，SE 诱导后 1 h 给予 AST 治疗。用脂多糖（Lipopolysaccharide，LPS）、AST、三磷酸腺苷（Adenosine Triphosphate，ATP）、2,3-O-4-苯甲酰基-4-苯甲酰基-ATP（2,3-O-Benzoyl-4-Benzoyl-ATP，BzATP）和氧化型三磷酸腺苷（Oxidized Adenosine Triphosphate，oxATP）处理大鼠小胶质细胞。对大鼠进行 Morris 水迷宫、免疫组织化学和尼氏染色实验。采用实时聚合酶链反应（Real-Time Polymerase Chain Reaction，RT-PCR）和 Western blot 检测大鼠和小胶质细胞中 P2X7R 和炎症细胞因子（如环氧化酶-2（Cyclooxygenase-2，Cox-2）、白细胞介素-1β（Interleukin-1β，IL-1β）和肿瘤坏死因子-α（Tumor Necrosis Factor-α，TNF-α））的表达。采用 ELISA 检测小胶质细胞中的 ATP 浓度。

结果

AST 缓解了 SE 诱导的海马损伤和认知功能障碍。AST 还能有效抑制 SE 大鼠大脑和小胶质细胞中的炎症，并下调 P2X7R 的表达。结果还表明，AST 降低了细胞外 ATP 水平，而细胞外 ATP 可增加 P2X7R 的表达。此外，BzATP 上调了小胶质细胞中 P2X7R 和炎症因子的表达，而 oxATP 则下调了 P2X7R 和炎症因子的表达。