Toll样受体4信号通路在蛛网膜下腔出血后早期脑损伤中的机制研究

Mechanisms of Toll-like receptor 4 singaling pathway in early brain damage following subarachnoid hemorrhage

摘要:

目的 观察蛛网膜下腔出血（SAH）后Toll样受体4（TLR4）、肿瘤坏死因子α（TNF-α）和干扰素β（IFN-β）的表达及其对SAH后早期脑损伤的影响，探讨SAH后早期脑损伤的可能发病机制。方法 健康成年雄性新西兰白兔36只，采用枕大池自体动脉血二次注血法制成蛛网膜下腔出血模型。实验动物随机分成对照组、SAH组和给药组，每组12只。对照组枕大池穿刺后注入生理盐水，SAH组造成蛛网膜下腔出血模型，给药组在造蛛网膜下腔出血模型后静脉注入Eritoran （E5564，1.5 mg/kg）。每天行神经功能评定。取右侧海马行实时荧光定量聚合酶链反应法（QPCR）检测TLR4、TNF-α和IFN-β的mRNA表达。结果 SAH组中TLR4、TNF-α和IFN-β的mRNA表达量较对照组明显增加（P<0.05），给药组TLR4、TNF-α和IFN-β的mRNA表达量较SAH组明显下降（P<0.05）。SAH组神经功能缺损较对照组明显严重（P<0.05），给药组经E5564干预后神经功能较SAH组得到改善（P<0.05）。结论 TLR4在蛛网膜下腔出血后的早期脑损伤中起到重要作用，其具体机制可能是通过TLR4介导的信号通路，而E5564对这一信号通路的抑制可减轻SAH后的脑损伤。

Abstract:

Objective To examine the expression of Toll-like receptor 4 (TLR4), tumor necrosis factor-alpha (TNF-α) and interferon-β (IFN-β) in the brain of rabbits with subarachnoid hemorrhage (SHA), and investigate the mechanisms of TLR4 signaling pathway in the early brain damage following SAH.Methods The SAH model of rabbits were prepared by injecting autologous arterial blood into the cisterna magna.A total of 36 rabbits were randomly divided into three groups: control, SAH and E5564 treatment (n=12 each).Normal saline and autologous arterial blood were injected into the cisterna magna in the control and SAH groups respectively.In the E5564 group, Eritoran (1.5 mg/kg) was administerd by vein injections (twice) after SAH inducement.The neurologic deficits were determined every day.The expression levels of TLR4, TNF-α and IFN-β mRNA in the hippocampus were measured by real-time quantitative PCR.Results The expression of TLR4, TNF-α and IFN-β mRNA in the SAH group was significantly higher than in the control group (P<0.05).The E5564 group showed obviously decreased the excpression of TLR4, TNF-α and IFN-β mRNA compared with the SHA gyoup (P<0.05).The neurologic deficits were improved in the E5564 group compared with the SAH group (P<0.05).Conclusions TLR4 may play a crucial role in the brain damage following SAH.The mechanisms may be associated with the TLR4 signaling pathway.E5564 may attenuate the brain damage following SAH by inhibiting TLR4.