缺血后处理对大鼠局灶性脑缺血再灌注损伤时TLR4 信号通路表达的影响

目的:观察缺血后处理对大鼠局灶性脑缺血再灌注损伤后TLR4通路表达的影响。方法:成年健康雄性SD大鼠110只,随机分为假手术组(sham组)(n=10)、缺血再灌注组(I/R组)和后处理组(IP组),后两组又依据缺血再灌注6h、12h、24h、48h、72h不同的时间点再分五个亚组。对各组行神经行为学评分,脑组织梗死体积测量,TUNEL技术检测神经细胞凋亡的情况,免疫组织化学技术观察各组大鼠脑组织TLR4、NF-κB和TNF-α蛋白的表达,原位杂交方法检测各组大鼠脑组织TLR4mRNA、NF-κBmRNA的表达。结果:缺血后处理可下调TLR4、NF-κB、TNF-α细胞炎性因子的表达,抑制细胞凋亡、减少脑梗死体积,改善神经行为。结论:后处理可通过抑制TLR4信号通路表达,减少脑梗死体积,改善神经功能。

Effects of Ischemic Postconditioning on TLR4 Signaling Pathway During Focal Cerebral Ischemla /Reperfusion in Rats

Objective:To investigate the effect of ischemic postconditioning on TLR4 signaling pathway during focal cerebral ischemic reperfusion in rats.Methods: One hundred and ten adult healthy male Sprague-Dawley rats were randomly divided into sham group(n=10),ischemia/reperfusion group and ischemic postconditioning group.The latter groups was equally divided into five subgroups according to different time points of the ischemia-reperfusion(6,12,24,48,and 72 h)(n=10),The models of focal brain ischemia were established by intraluminal thread middle cerebral artery occlusion(MCAO) methods.For IP,the rats were subjected to 3 cycles of 15-second/15-second reperfusion/reocclusion after 2 h MCAO.Each group was evaluated with examinating neurobehavioral function deficit scores and infarct volume.The apoptotic cells were counted by TUNEL method.The immunohistochemistry stain was used to determine the expressions of TLR4,NF-κ B and tumor necrosis factor-α(TNF-α).The levels of TLR4mRNA and NF-κ BmRNA were examined by In Situ Hybridization(ISH).Results: Ischemic postconditioning could down-regulate the expressions of TLR4,NF-κ B and TNF-α,inhibit apoptosis,reduce the cerebral infarct volumes,and improve the neurobehavioral function of rats.Conclusions: IP could reduce the infarct volumes and improve neurobehavioral function through inhibiting the expressions of TLR4 signaling pathway.