PI3K/Akt/mTOR信号通路在TRALI大鼠发病机制中的作用研究

Role of PI3K/Akt/mTOR signaling pathway in the pathogenesis of transfusion-related acute lung injury in rats

目的研究PI3K/Akt/mTOR信号通路在TRALI发病机制中的作用。方法构建输血相关急性肺损伤大鼠模型,采用的方法为创伤后失血,再大量输血,通过HE染色确定肺组织病理学改变。ELISA和RT-qPCR检测TRALI大鼠外周血/肺组织中TNF-α、IL-6和IL-1β蛋白和mRNA表达水平;Western blot检测PI3K/Akt/mTOR信号通路活化及凋亡蛋白Bax、Bcl-2和Caspase3的表达水平。结果TRALI大鼠肺泡组织结构严重受损,炎细胞浸润,水肿明显;TNF-α、IL-6和IL-1β表达水平明显增加(P<0.05);PI3K/Akt/mTOR信号通路被活化,p-mTOR/mTOR表达明显增加,并抑制了凋亡蛋白Bax和Caspase3的表达,增加了抗凋亡蛋白Bcl-2的表达(P<0.05)。结论mTOR作为一个有潜力的药物靶点,由于其作用机制的复杂性,界定其发挥保护和损伤作用的确切时间靶点,选择最佳用药时间是临床防控TRALI发生发展的重要手段。

Objective To study the role of the phosphoinositide 3-kinase(PI3K)/Akt/mammalian target of rapamycin(mTOR)signaling pathway in the pathogenesis of transfusion-related acute lung injury(TRALI)in rats.Methods A rat model of TRALI was established via trauma-blood loss-massive transfusion,and pulmonary histopathological changes were detected by hematoxylin and eosin staining.Protein and mRNA expression levels of tumor necrosis factor(TNF)-α,interleukin(IL)-6,and IL-1βin peripheral blood or lung tissues were detected by enzymelinked immunosorbent assay and quantitative reverse transcription-polymerase chain reaction,respectively.Expression levels of PI3K/Akt/mTOR signaling pathway-related proteins and of the apoptosis-related proteins Bax,Bcl-2,and Caspase3 were detected by Western blot.Results Alveolar tissue structure was seriously damaged and inflammatory cell infiltration and edema were evident in TRALI model rats.Expression levels of the inflammatory cytokines TNF-α,IL-6,and IL-1βwere significantly increased in peripheral blood and lung tissues(P<0.05).The PI3K/Akt/mTOR signaling pathway was activated,the p-mTOR/mTOR ratio was significantly increased,expression levels of the apoptotic proteins Bax and Caspase3 were inhibited,and expression of the anti-apoptotic protein Bcl-2 was increased(P<0.05).Conclusions mTOR,as a potential drug target,may represent an important strategy for the clinical prevention and control of TRALI,by defining the exact timings of its protective and damaging effects and selecting the optimal medication time,in light of the complex mechanism of TRALI.