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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3 h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)m RNA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 m RNA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。
Objective To investigate the changes of hypoxia inducible factor-1α (HIF-1α) induced by Toll-like receptor 4 (TLR4) signaling pathway in rat lung ischemia-reperfusion injury (IRI) model. Methods Forty-eight healthy male Sprague-Dawley rats were randomly divided into sham-operation group, IRI model group, TLR4-activated group (intervention with lipopolysaccharide) and TLR4 inhibition group (TAK-242 intervention) mouse. Rats in IRI model group and sham operation group received intravenous injection of normal saline at 3 weeks before injection. Lipopolysaccharide was injected intravenously in TLR4-activated group, and TAK-242 was intravenously injected in TLR4-inhibited group once a week for 3 weeks. The models of lung ischemia-reperfusion injury were established in IRI model group, TLR4-activated group and TLR4 inhibition group at 30 min after the last injection. In addition to sham-operated group did not block the hilar and other methods of operation with the former. The expression of Toll-like receptor 4 (TLR4), hypoxia-inducible factor-1α (HIF-1α) and tumor necrosis factor-α (TNF-α) in lung tissue were detected by reverse transcription polymerase chain reaction (RT- (TNF-α) and interleukin-6 (IL-6) m RNA were detected by Western blot. The expressions of TLR4, HIF-1α, TNF-α and IL- -6 protein expression level. Results Lung wet weight / dry weight in IRI model group was significantly higher than that in sham operation group (P <0.05), TLR4 activation group was higher than IRI model group (P <0.05), TLR4 inhibition group was lower than IRI model group (P <0.05). The expression of TLR4, HIF-1α, TNF-α, IL-6 mRNA and protein in lung tissue of IRI model group were higher than those of sham operation group and TLR4 activation group (P <0.05) TLR4 inhibition group was lower than IRI model group (P <0.05). Conclusions After lung IRI in rats, TLR4 signaling pathway in lungs mediates a significant increase in the level of HIF-1α, which may increase the degree of inflammatory damage to lung tissue.