Increasing evidence has revealed that the uncontrolled thrombin-induced inflammation following intracerebral hemorrhage (ICH) plays a key role in ICH. Oxidative stress and neuroinflammatory responses are interdependent and bidirectional events. Melatonin is now recognized as an antioxidant and a free radical scavenger due to its roles in various physiological and pathological processes. The aim of this study was to explore the molecular mechanisms underlying the effects of melatonin on thrombin-induced microglial inflammation and its indirect protection of HT22 cells from p53-associated apoptosis. Melatonin treatment attenuated the expression of IL-1β, IL-18, cleaved caspase-1, and NLRP3 and decreased the production of reactive oxygen species (ROS), revealing its inhibitory effects against ROS-NLRP3 inflammasome activation. In further experiments investigating the protection conferred by melatonin, incubating HT22 cells with conditioned medium (CM) from thrombin-stimulated microglia induced HT22 cell apoptosis, and this effect was reversed after treating CM with either melatonin or N-acetyl-L-cysteine (NAC). Additionally, the Bax/Bcl-2 ratio and the levels of cleaved caspase-3 and p53 were markedly lower in the cells cultured in thrombin + melatonin-CM than in the cells cultured in thrombin-CM. Furthermore, the levels of MMP, ROS, SOD, MDA, and GSH-PX in bystander HT22 cells suggested that melatonin decreased HT22 cell apoptosis instigated via the p53-associated apoptotic pathway. Therefore, these findings strongly indicate the anti-inflammatory properties of melatonin that may suppress ROS-NLRP3 inflammasome activation and protect HT22 cells against apoptosis by inhibiting the ROS-mediated p53-dependent mitochondrial apoptotic pathway.

中文翻译：

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Melatonin 减弱 BV2 细胞中凝血酶诱导的炎症，然后保护 HT22 细胞免于细胞凋亡。

越来越多的证据表明，脑出血 (ICH) 后不受控制的凝血酶诱导的炎症在 ICH 中起着关键作用。氧化应激和神经炎症反应是相互依赖的双向事件。由于褪黑激素在各种生理和病理过程中的作用，它现在被认为是一种抗氧化剂和自由基清除剂。本研究的目的是探索褪黑激素对凝血酶诱导的小胶质细胞炎症的影响及其间接保护 HT22 细胞免受 p53 相关细胞凋亡的分子机制。褪黑激素处理减弱了 IL-1β、IL-18、裂解的 caspase-1 和 NLRP3 的表达并减少了活性氧 (ROS) 的产生，揭示了其对 ROS-NLRP3 炎症小体激活的抑制作用。在进一步研究褪黑激素赋予的保护作用的实验中，将 HT22 细胞与来自凝血酶刺激的小胶质细胞的条件培养基 (CM) 一起孵育诱导 HT22 细胞凋亡，并且在用褪黑激素或 N-乙酰-L-半胱氨酸 (NAC) 处理 CM 后，这种作用被逆转）。此外，在凝血酶 + 褪黑激素-CM 中培养的细胞中，Bax/Bcl-2 比率以及裂解的 caspase-3 和 p53 的水平明显低于在凝血酶-CM 中培养的细胞。此外，旁观者 HT22 细胞中 MMP、ROS、SOD、MDA 和 GSH-PX 的水平表明，褪黑激素减少了通过 p53 相关凋亡途径引发的 HT22 细胞凋亡。所以，