百里酚通过抑制小胶质细胞介导的神经炎症改善缺血性脑损伤。

Thymol improves ischemic brain injury by inhibiting microglia-mediated neuroinflammation.

机构信息

Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing 210008, China; Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China.

Department of Neurology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210008, China; Department of Neurology, Nanjing Drum Tower Hospital, State Key Laboratory of Pharmaceutical Biotechnology and Institute of Translational Medicine for Brain Critical Diseases, Nanjing University, Nanjing 210008, China.

出版信息

Brain Res Bull. 2024 Sep;215:111029. doi: 10.1016/j.brainresbull.2024.111029. Epub 2024 Jul 14.

DOI:10.1016/j.brainresbull.2024.111029

PMID:39009094

Abstract

BACKGROUND

Microglia-mediated inflammation is a critical factor in the progression of ischemic stroke. Consequently, mitigating excessive microglial activation represents a potential therapeutic strategy for ischemic injury. Thymol, a monophenol derived from plant essential oils, exhibits diverse beneficial biological activities, including anti-inflammatory and antioxidant properties, with demonstrated protective effects in various disease models. However, its specific effects on ischemic stroke and microglial inflammation remain unexplored.

METHODS

Rodent transient middle cerebral artery occlusion (tMCAO) model was established to simulate ischemic stroke. TTC staining, modified neurological function score (mNSS), and behavioral tests were used to assess the severity of neurological damage. Then immunofluorescence staining and cytoskeleton analysis were used to determine activation of microglia. Lipopolysaccharide (LPS) was utilized to induce the inflammatory response of primary microglia in vitro. Quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and enzyme-linked immunosorbent assay (ELISA) were performed to exam the expression of inflammatory cytokines. And western blot was used to investigate the mechanism of the anti-inflammatory effect of thymol.

RESULTS

In this study, we found that thymol treatment could ameliorate post-stroke neurological impairment and reduce infarct volume by mitigating microglial activation and pro-inflammatory response (IL-1β, IL-6, and TNF-α). Mechanically, thymol could inhibit the phosphorylation of phosphatidylinositol-3-kinase (PI3K), sink serine/threonine kinase (Akt), and mammalian target of rapamycin (mTOR), thereby suppressing the activation of nuclear factor-κB (NF-κB).

CONCLUSIONS

Our study demonstrated that thymol could reduce the microglial inflammation by targeting PI3K/Akt/mTOR/NF-κB signaling pathway, ultimately alleviating ischemic brain injury. These findings suggest that thymol is a promising candidate as a neuroprotective agent against ischemic stroke.

摘要

背景

小胶质细胞介导的炎症是缺血性中风进展的关键因素。因此，减轻过度的小胶质细胞激活可能是缺血性损伤的一种潜在治疗策略。百里酚是一种源自植物精油的单酚，具有多种有益的生物学活性，包括抗炎和抗氧化特性，在各种疾病模型中表现出保护作用。然而，其对缺血性中风和小胶质细胞炎症的具体作用仍未得到探索。

方法

建立了啮齿动物短暂性大脑中动脉闭塞（tMCAO）模型，模拟缺血性中风。TTC 染色、改良神经功能评分（mNSS）和行为测试用于评估神经损伤的严重程度。然后，通过免疫荧光染色和细胞骨架分析来确定小胶质细胞的激活情况。利用脂多糖（LPS）诱导体外原代小胶质细胞的炎症反应。采用实时定量聚合酶链反应（qRT-PCR）、western blot 和酶联免疫吸附试验（ELISA）检测炎症细胞因子的表达。western blot 用于研究百里酚抗炎作用的机制。

结果

在这项研究中，我们发现百里酚治疗可通过减轻小胶质细胞激活和促炎反应（IL-1β、IL-6 和 TNF-α）来改善中风后的神经损伤和减少梗死体积。机制上，百里酚可抑制磷脂酰肌醇-3-激酶（PI3K）、丝氨酸/苏氨酸激酶（Akt）和哺乳动物雷帕霉素靶蛋白（mTOR）的磷酸化，从而抑制核因子-κB（NF-κB）的激活。