TLR4与TNF-α在脑缺血再灌注小鼠海马CA1区神经元中的表达

The expression of TLR4 and TNF-α during cerebral ischemia reperfusion in hippocampal CA1 region in mice

目的:探讨Toll样受体4(TLR4)在脑缺血再灌注损伤炎症反应中的作用。方法:采用抗TLR4抗体封闭阻断TLR4,应用HE染色观察小鼠海马CA1区组织病理学改变、Western Blot和RT-PCR检测海马TLR4蛋白和mRNA表达量,免疫组化方法检查TNF-α表达。小鼠随机分为3组,即假手术组(S组)、缺血再灌注组(I组)和TLR4阻断组(T组),各组又分12,24,48和72h4个时间点组。结果:缺血再灌注组TLR4蛋白、TLR4 mRNA和TNF-α表达水平明显高于假手术组表达水平(P<0.05),而TLR4阻断组TLR4蛋白、TLR4 mRNA和TNF-α表达水平明显少于缺血再灌注组(P<0.05)。相关分析表明,TLR4 mRNA表达水平与TNF-α含量呈显著正相关(P<0.01)。结论:本结果提示缺血再灌注可激活TLR4,TLR4在脑缺血再灌注损伤中起重要作用;炎性因子TNF-α的产生、分泌可能与TLR4 mRNA表达存在密切联系。

Objective：To study the role of Toll-like receptor 4（TLR4）during the inflammatory reaction induced by cerebral ischemia reperfusion in mice. Methods：After blockade of TLR4 by anti-TLR4 antibody,the pathological change of hippocampal CA1 region was observed by HE （Haematoxylin-Eosin） staining,and the expression of TLR4 at the protein and mRNA level in hippocampus was examined by Western blot and RT-PCR,respectively; the expression of TNF-α was examined by immunohistochemistry. Mice were randomly divided into sham group （S）,ischemia reperfusion group （I ） and TLR4 blocked group （T） at different time points （12,24,48 and 72 h）. Results：The results showed that on the right side of hippocampus CA1 region,TLR4 protein,TLR4 mRNA and TNF-α expression of I group was distinctly higher than that of S group（P〈0.05）,while TLR4 protein,TLR4 mRNA and TNF-α expression of T group was significantly lower than that of I group（P〈0.05）. Related analysis showed that distinct positive correlation was observed between TLR4mRNA expression level and TNF-α content （P〈0.01）. Conclusion：Our results indicate that TLR4,which plays an important role in cerebral ischemia reperfusion injury,is activated by cerebral ischemia reperfusion in hippocampus CA1 region in mice and the production and externalization of inflammatory factor TNF-α may be closely related to TLR4mRNA expression.