大鼠肺缺血再灌注损伤模型中TLR4信号通路介导HIF-1α的变化及其意义

摘要

Objective To investigate the changes and significance of hypoxia inducible factor-1α (HIF-1α) mediated by Toll like receptor 4 (TLR4) signal pathway in the model of lung ischemia reperfusion injury (IRI) rats.Methods A total of 48 healthy male SD rats were selected and randomly divided into sham operation group,IRI model group,TLR4 activation group (LPS intervention) and TLR4 inhibition group (TAK-242 intervention) with 12 rats in each group.3 weeks before model,IRI model group and sham operation group were injected with saline,TLR4 activation group was injected with lipopolysaccharide,TLR4 inhibition group was injected with TAK-242,once a week for three weeks.IRI model group,TLR4 activation group and TLR4 inhibition group were established a model of lung ischemia-reperfusion injury after last injection 30 minutes,sham operation group was treated same as the other groups except for not block the lung door.3 hours after reperfusion injury,TLR4,HIF-1α,tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) mRNA expression of lung tissue were tested by reverse transcriptase polymerase chain reaction (RT-PCR).TLR4,HIF-1α,TNF-α and IL-6 protein expression of lung tissue were tested by Western-blot.Results The lung wet weight/ dry weight ratio of the IRI model group was higher than that of the sham operation group (P ＜ 0.05),the TLR4 activation group was higher than that of the model group (P ＜ 0.05),and the TLR4 inhibition group was lower than that of the model group (P ＜ 0.05).The mRNA and protein expression levels of TLR4,HIF-1α,TNF-α,IL-6 in the lung tissues of IRI model group were higher than those of the sham operation group (P ＜ 0.05),the TLR4 activation were higher than those of the model group (P ＜ 0.05),and the TLR4 inhibition group were lower than those of the model group (P ＜ 0.05).Conclusion The TLR4 signal pathway in the lung tissue mediates the HIF-1α expression increased significantly after lung ischemia-reperfusion injury in rats,and increases the degree of inflammatory damage to the lung tissue.%目的 探讨大鼠肺缺血再灌注损伤(IRI)模型中Toll样受体4(TLR4)信号通路介导缺氧诱导因子-1α(HIF-1α)的变化及其意义.方法 选取48只健康雄性SD大鼠,采用随机数字表法分为假手术组、IRI模型组、TLR4激活组(脂多糖干预)、TLR4抑制组(TAK-242干预),每组各12只大鼠.造模前3周时,IRI模型组和假手术组静脉注射生理盐水,TLR4激活组静脉注射脂多糖,TLR4抑制组静脉注射TAK-242,每周1次,连续3周.IRI模型组、TLR4激活组和TLR4抑制组均于末次注射30 min后建立肺缺血再灌注损伤模型.假手术组除不阻断肺门外,其他操作方法同前.再灌注损伤后3h采用逆转录聚合酶联反应(RT-PCR)检测各组大鼠肺组织中Toll样受体4(TLR4)、缺氧诱导因子-1α(HIF-1α)、肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)mRNA表达,采用免疫印迹法(Western-blot)检测各组大鼠肺组织中TLR4、HIF-1α、TNF-α和IL-6蛋白表达水平.结果 肺湿重/干重值IRI模型组高于假手术组(P＜0.05),TLR4激活组高于IRI模型组(P＜0.05),TLR4抑制组低于IRI模型组(P＜0.05);肺组织中TLR4、HIF-1α、TNF-α、IL-6 mRNA和蛋白表达水平IRI模型组高于假手术组(P＜ 0.05),TLR4激活组高于IRI模型组(P＜0.05),TLR4抑制组低于IRI模型组(P＜0.05).结论 大鼠肺IRI后,肺组织中TLR4信号通路介导HIF-1α的水平显著升高,会增加对肺组织的炎症损伤程度.