敲低S100A9对大鼠脑缺血再灌注损伤、炎症反应的影响及其机制

Effects of S100A9 knockdown on cerebral I/R injury and inflammation in rats and the mechanism

目的观察敲低S100A9对大鼠脑缺血再灌注损伤、炎症反应的影响并探讨其相关机制。方法SD大鼠随机分为假手术组、模型组、Lsh-NC组、Lsh-S100A9组,模型组、Lsh-NC组、Lsh-S100A9组采用线栓法制备大脑中动脉闭塞(MCAO)模型,假手术组仅暴露颈总动脉及埋线处理;Lsh-S100A9组、Lsh-NC组在造模24 h后进行S100A9敲低慢病毒及空载体脑内注射。采用RT-qPCR法检测各组大鼠脑组织S100A9 mRNA表达,NSS评分评价各组大鼠神经功能缺损程度,TTC染色测算各组大鼠脑组织梗死体积,ELISA法检测各组大鼠脑组织IL-1β、IL-6、TNF-α;Western blotting法检测Lsh-NC组、Lsh-S100A9组大鼠脑组织NF-κB信号通路相关蛋白p65、p-p65及MyD88。结果S100A9 mRNA表达模型组、Lsh-NC组>假手术组>Lsh-S100A9组;神经功能缺损程度评分、缺血侧脑梗死体积及脑组织IL-1β、IL-6、TNF-α表达模型组、Lsh-NC组>Lsh-S100A9组>假手术组(P均<0.05)。Lsh-S100A9组脑组织p-p65、MyD88蛋白表达低于Lsh-NC组(P均<0.01)。结论敲低S100A9可减轻MCAO大鼠脑缺血再灌注损伤,抑制脑组织炎症反应,其机制可能与调控NF-κB信号通路影响炎症反应有关。

Objective To investigate the effects of S100A9 knockdown on cerebral ischemia-reperfusion(I/R)inju⁃ry and inflammation in rats and to explore the related mechanism.Methods SD rats were randomly divided into the sham operation group,model group,Lsh-NC group,and Lsh-S100A9 group,respectively.The middle cerebral artery oc⁃clusion(MCAO)models were prepared by intraluminal suture method in the model group,Lsh-NC group,and Lsh-S100A9 group;the rats in the sham operation group only received the carotid artery exposure and wire embedding;in the Lsh-S100A9 group and Lsh-NC group,rats received S100A9 knockdown lentivirus or empty vector intracerebral injection at 24 h after modeling.RT-qPCR was used to detect S100A9 mRNA expression in the brain tissues of rats;neurological se⁃verity score(NSS)score was used to evaluate the degree of neurological impairment;infarct volume of brain tissue was measured by 2,3,5-triphenyltetrazolium chloride(TTC)staining;and IL-1β,IL-6 and tumor necrosis factor-α(TNF-α)were detected by ELISA.The protein expression levels of p65,phosphorylated p65(p-p65)and MyD88 in the brain tis⁃sues of rats in the Lsh-NC group and Lsh-S100A9 group were detected by Western blotting.Results S100A9 mRNA ex⁃pression level was as follows:the model group,Lsh-NC group>sham operation group>Lsh-S100A9 group;the neurologi⁃cal impairment score,ischemic cerebral infarction volume and IL-1β,IL-6,TNF-αexpression levels in the brain tissues were in the following order:the model group,Lsh-NC group>Lsh-S100A9 group>sham operation group(both P<0.05).The expression levels of p-p65 and MyD88 protein in the Lsh-S100A9 group were lower than those in the Lsh-NC group(all P<0.01).Conclusion S100A9 knockdown can alleviate the cerebral I/R injury and inhibit brain inflammation in MCAO rats.The mechanism may be related to the regulation of NF-κB signaling pathway to affect the inflammatory re⁃sponse.