Department of Biopharmaceutical Sciences, College of Pharmacy, Harbin Medical University, Heilongjiang; and.
The Ninth People's Hospital, School of Medicine, Shanghai Jiaotong University, China.
J Neurosurg. 2017 Sep;127(3):522-531. doi: 10.3171/2016.7.JNS1668. Epub 2016 Oct 14.
OBJECTIVE In this study, the authors investigated the involvement of 15( S)-hydroxyeicosatetraenoic acid (15(S)-HETE) in the regulation of peroxisome proliferator-activated receptor-γ (PPARγ) after intracerebral hemorrhage (ICH) and its effects on hemorrhage-induced inflammatory response and oxidative stress in an experimental rodent model. METHODS To simulate ICH in a rat model, the authors injected autologous whole blood into the right striatum of male Sprague-Dawley rats. The distribution and expression of 12/15-lipoxygenase (12/15-LOX) were determined by immunohistochemistry and Western blot analysis, respectively. Immunofluorescent double labeling was used to study the cellular localization of 12/15-LOX, and 15(S)-HETE was measured with a 15(S)-HETE enzyme immunoassay kit. Neurological deficits in the animals were assessed through behavioral testing, and apoptotic cell death was determined with terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick-end labeling. RESULTS Rats with ICH had increased expression of 12/15-LOX predominantly in neurons and also in oligodendrocytes, astrocytes, and microglia. Moreover, ICH elevated production of 15(S)-HETE in the brain area ipsilateral to the blood injection. The PPARγ agonist, exogenous 15(S)-HETE, significantly increased PPARγ protein levels and increased PPARγ-regulated gene (i.e., catalase) expression in the ICH rats. Reduced expression of the gene for the proinflammatory protein nuclear factor κB coincided with decreased neuron damage and improved functional recovery from ICH. A PPARγ antagonist, GW9662, reversed the effects of exogenous 15(S)-HETE on the PPARγ-regulated genes. CONCLUSIONS The induction of 15(S)-HETE during simulated ICH suggests generation of endogenous signals of neuroprotection. The effects of exogenous 15(S)-HETE on brain hemorrhage-induced inflammatory responses and oxidative stress might be mediated via PPARγ.
本研究旨在探讨 15( S)-羟基二十碳四烯酸（15(S)-HETE）在脑出血（ICH）后对过氧化物酶体增殖物激活受体-γ（PPARγ）的调节作用及其对实验性啮齿动物模型中出血引起的炎症反应和氧化应激的影响。
为了在大鼠模型中模拟 ICH，作者将自体全血注入雄性 Sprague-Dawley 大鼠右侧纹状体。通过免疫组织化学和 Western blot 分析分别确定 12/15-脂氧合酶（12/15-LOX）的分布和表达。免疫荧光双标记用于研究 12/15-LOX 的细胞定位，并用 15(S)-HETE 酶免疫测定试剂盒测量 15(S)-HETE。通过行为测试评估动物的神经功能缺损，并用末端脱氧核苷酸转移酶介导的生物素化 dUTP 缺口末端标记法测定凋亡细胞死亡。
ICH 大鼠的神经元中 12/15-LOX 的表达增加，在少突胶质细胞、星形胶质细胞和小胶质细胞中也有表达。此外，ICH 增加了脑内注射侧 15(S)-HETE 的产生。PPARγ 激动剂外源性 15(S)-HETE 显著增加了 ICH 大鼠的 PPARγ 蛋白水平，并增加了 PPARγ 调节基因（即过氧化氢酶）的表达。促炎蛋白核因子κB 的基因表达减少与神经元损伤减少和 ICH 后功能恢复改善相一致。PPARγ 拮抗剂 GW9662 逆转了外源性 15(S)-HETE 对 PPARγ 调节基因的作用。
在模拟 ICH 期间诱导 15(S)-HETE 表明产生了内源性神经保护信号。外源性 15(S)-HETE 对脑出血引起的炎症反应和氧化应激的影响可能通过 PPARγ 介导。
