College of Integrated Traditional Chinese and Western Medicine, Gansu University of Chinese Medicine, Lanzhou, Gansu 730000, China; Affiliated Hospital of Gansu University of Chinese Medicine, Lanzhou, Gansu 730000, China; Tianjin Key Laboratory of Neurotrauma Repair, Pingjin Hospital Brain Center, Characteristic Medical Center of PAPF, Tianjin 300162, China.
Tianjin Key Laboratory of Neurotrauma Repair, Pingjin Hospital Brain Center, Characteristic Medical Center of PAPF, Tianjin 300162, China.
Brain Res. 2020 Jul 15;1739:146818. doi: 10.1016/j.brainres.2020.146818. Epub 2020 Apr 7.
Traumatic brain injury (TBI) is a major leading cause of death and long-term disability. Although astrocytes play a key role in neuroprotection after TBI in the early stage, the overactivation of astrocytes can lead to long-term functional deficits, and the underlying pathophysiological mechanisms remain unclear. In addition, it is unknown whether the nuclear factor erythroid 2-related factor2/haem oxygenase-1 (Nrf-2/HO-1) pathway could elicit a neuroprotective effect by decreasing astrocyte overactivation after TBI. We aimed to study the effects of tert-butylhydroquinone (TBHQ) in reducing astrocyte overactivation after TBI and explored the underlying mechanisms. We first established a controlled cortical impact (CCI) model in rats and performed Haematoxylin and eosin (H&E) staining to observe brain tissue damage. The cognitive function of rats was assessed by modified neurological severity scoring (mNSS) and Morris water maze (MWM) test. Astrocyte and microglia activation was detected by immunofluorescence staining. Oxidative stress conditions were investigated using Western blotting. An enzyme-linked immunosorbent assay (ELISA) was designed to assess the level of the proinflammatory factor tumour necrosis factor-alpha (TNF-α). Dihydroethidium (DHE) staining was used to detect reactive oxygen species (ROS). Apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The results showed that the administration of TBHQ ameliorated motor function and cognitive deficits and decreased the lesion volume. In addition, TBHQ significantly decreased astrocyte overactivation, diminished the pro-inflammatory phenotype M1 and inflammatory cytokines production after TBI, increased Nrf-2 nuclear accumulation, and enhanced the levels of the Nrf-2 downstream antioxidative genes HO-1 and NADPH-quinone oxidoreductase-1 (NQO-1). Furthermore, TBHQ treatment alleviated apoptosis and neuronal death in the cerebral cortex. Overall, our data indicated that the upregulation of Nrf-2 expression could enhance neuroprotection and decrease astrocyte overactivation and might represent a new theoretical basis for treating TBI.
创伤性脑损伤（TBI）是导致死亡和长期残疾的主要原因。尽管星形胶质细胞在 TBI 后的早期阶段对神经保护起着关键作用，但星形胶质细胞的过度激活会导致长期的功能缺陷，其潜在的病理生理机制尚不清楚。此外，尚不清楚核因子红细胞 2 相关因子 2/血红素加氧酶-1（Nrf-2/HO-1）途径是否可以通过减少 TBI 后星形胶质细胞的过度激活来发挥神经保护作用。我们旨在研究 tert-butylhydroquinone（TBHQ）在减少 TBI 后星形胶质细胞过度激活方面的作用，并探讨其潜在机制。我们首先在大鼠中建立了控制性皮质撞击（CCI）模型，并进行苏木精和伊红（H&E）染色观察脑组织损伤。改良神经损伤评分（mNSS）和 Morris 水迷宫（MWM）测试评估大鼠的认知功能。通过免疫荧光染色检测星形胶质细胞和小胶质细胞的激活。通过 Western blot 检测氧化应激情况。设计酶联免疫吸附试验（ELISA）评估促炎因子肿瘤坏死因子-α（TNF-α）的水平。二氢乙啶（DHE）染色检测活性氧（ROS）。末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）染色评估细胞凋亡。结果表明，TBHQ 给药可改善运动功能和认知缺陷，减少损伤体积。此外，TBHQ 可显著减少 TBI 后星形胶质细胞的过度激活，减少促炎表型 M1 和炎症细胞因子的产生，增加 Nrf-2 的核积累，并增强 Nrf-2 下游抗氧化基因 HO-1 和 NADPH-醌氧化还原酶-1（NQO-1）的水平。此外，TBHQ 治疗可减轻皮质中的细胞凋亡和神经元死亡。总体而言，我们的数据表明，上调 Nrf-2 表达可以增强神经保护作用，减少星形胶质细胞的过度激活，并可能为治疗 TBI 提供新的理论依据。
