OSI-027抑制mTOR信号通路减轻高氧诱导的幼鼠肺损伤

OSI-027 alleviates hyperoxia-induced lung injury in juvenile rats by inhibiting the mTOR signaling pathway

摘要:

目的：探讨哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）1/2双重抑制剂OSI-027对高体积分数氧（高氧）致sprague-dawley（SD）幼鼠肺损伤及纤维化的抑制作用。方法：72只3周龄SD幼鼠随机分为空气+生理盐水、高氧+生理盐水、高氧+雷帕霉素和高氧+OSI-027组，分别建立动物模型（各组n=18）。高氧干预采用90%氧气持续处理，生理盐水、雷帕霉素、OSI-027干预分别于观察期第1、3、6、8、10、13天经腹腔注射给药，在造模第3、7、14天取各组幼鼠测量体质量变化、肺湿干重比（wet/dry ratio，W/D）、肺组织病理学检查、肺损伤评分、肺泡间隔厚度测定、肺组织免疫组化和蛋白印迹检测mTOR及磷酸化核糖体S6蛋白激酶（pS6K1）蛋白在肺组织的分布和表达。结果：从时间因素看，各组幼鼠体质量（F时间=297.098，P=0.000）、mTOR免疫组化（F时间=379.978，P=0.000）、mTOR（F时间=166.991，P=0.000）和pS6K1（F时间=122.676，P=0.000）蛋白水平都随时间延长而增加。除空气组外，其余各组肺损伤评分（F时间=1410.362，P=0.000）、肺泡间隔厚度（F时间=356.312，P=0.000）、pS6K1免疫组化（F时间=57.992，P=0.000）都随时间延长而升高，肺W/D（F时间=28.915，P=0.000）第3、7天时升高，第14天时下降。从分组因素看，体质量（F分组=176.597，P=0.000）空气组明显高于其他组，肺W/D（F分组=28.484，P=0.000）和肺泡间隔厚度（F分组=296.223，P=0.000）空气组明显低于其他组，除第3天外，mTOR免疫组化（F分组=134.100，P=0.000）高氧组明显高于其他组，PS6K1免疫组化（F分组=234.697，P=0.000）、mTOR（F分组=59.377，P=0.000）和 PS6K1（F分组=101.837，P=0.000）蛋白印迹高氧组明显高于其他组，肺损伤评分（F分组=2 420.076，P=0.000）高氧雷帕组明显高于其他组，高氧OSI组明显低于高氧组和高氧雷帕组。结论：高浓度氧可激活肺组织mTOR信号途径；mTOR可能促进了高氧肺损伤纤维化的发生发展，其调控机制可能与抑制mTOR信号通路的活化有关。mTOR复合物1/2（mTORC1/2）双重抑制剂OSI-027能减轻高氧致SD幼鼠肺损伤及纤维化。

Abstract:

Objective：To investigate the inhibitory effect of the mammalian target of rapamycin（mTOR） 1/2 dual inhibitor OSI-027 on hyperoxia-induced lung injury and fibrosis in juvenile Sprague-Dawley（SD） rats. Methods：A total of 72 juvenile SD rats aged 3 weeks were randomly divided into air+normal saline group，hyperoxia+normal saline group，hyperoxia+rapamycin group，and hyperoxia+OSI-027 group，with 18 rats in each group. An animal model was established. Hyperoxia intervention was performed with 90% oxygen，and normal saline，rapamycin，and OSI-027 interventions were performed via intraperitoneal injection on days 1，3，6，8，10，and 13 of observation，respectively. On days 3，7，and 14，the change in body weight，lung wet/dry（W/D） ratio，lung injury scores，and alve－olar septal thickness were measured；lung histopathological ex－amination was performed；immunohistochemistry and Western blot were used to evaluate the distribution and expression of mTOR and phosphorylated ribosomal S6 kinase（pS6K1） in lung tissue. Results：As for the factor of time，there were significant increases over time in body weight（Ftime=297.098，P=0.000），immunohistochemistry of mTOR（Ftime=379.978，P=0.000），mTOR（Ftime=166.991，P=0.000），and pS6K1（Ftime=122.676，P=0.000）. All groups except the air+normal saline group had significant increases in lung injury scores（Ftime=1 410.362，P=0.000），alveolar septum thickness（Ftime=356.312，P=0.000），and pS6K1 immunohistochem－istry（Ftime=57.992，P=0.000） over time，as well as an increase in lung W/D ratio on days 3 and 7（Ftime=28.915，P=0.000） and a reduction in lung W/D ratio on day 14. As for the factor of grouping，the air+normal saline group had a significantly higher body weight（Fgroup=176.597，P=0.000） and significantly lower lung W/D ratio（Fgroup=28.484，P=0.000） and alveolar septum thickness（Fgroup=296.223，P=0.000） than the other groups. At all time points except day 3，the hyperoxia+normal saline group had significantly higher mTOR immunohistochemistry（Fgroup=134.100，P=0.000），pS6K1 immunohistochemistry（Fgroup=234.697，P=0.000），mTOR（Fgroup=59.377，P=0.000），and pS6K1（Fgroup=101.837，P=0.000） than the other groups；the hyperoxia+rapamycin group had significantly higher lung injury scores than the other groups（Fgroup=2 420.076，P=0.000），and the hyperoxia+OSI-027 group had significantly lower scores than the hyperox－ia+normal saline group and the hyperoxia+rapamycin group. Conclusion：A high concentration of oxygen can activate the mTOR sig－naling pathway in lung tissue；mTOR may promote the development and progression of hyperoxia-induced pulmonary fibrosis，possibly by inhibiting activation of the mTOR signaling pathway. OSI-027 can alleviate hyperoxia-induced lung injury and fibrosis in juvenile SD rats.