PM_(2.5)激活HIF-1α-NF-κB/VEGF通路对肺损伤的影响

PM_(2.5)aggravates lung injury by activating HIF-1α-NF-κB/VEGF pathway

目的分析HIF-1α在PM_(2.5)暴露致肺损伤中的影响。方法构建经气管滴注PM_(2.5)悬液诱导大鼠肺损伤的动物模型,通过蛋白质免疫印迹、病理切片、ROS与TUNEL染色和ELISA等方法,分析不同PM_(2.5)暴露剂量下HIF-1α表达和肺损伤情况;构建抑制HIF-1α表达的动物模型,通过蛋白质免疫印迹、免疫荧光和ELISA等方法探讨HIF-1α在PM_(2.5)暴露致肺损伤中的作用机制。结果PM_(2.5)暴露造成肺组织病理性损伤,提高肺组织ROS水平、细胞凋亡率和湿干比,促进支气管肺泡灌洗液中各类炎症细胞计数和炎症因子IL-6、TNF-α水平增高,激活肺组织HIF-1α的蛋白表达,且以上效应与PM_(2.5)暴露浓度相关;抑制HIF-1α可降低NF-κB表达,降低支气管肺泡灌洗液中炎症因子水平,改善肺组织炎症;抑制HIF-1α可降低VEGF表达,降低支气管肺泡灌洗液中白蛋白水平和肺组织湿干比,改善肺组织水肿。结论PM_(2.5)通过激活“HIF-1α-NF-κB-炎症细胞(AMs、NEUs)/炎症因子(IL-6、TNF-α)-肺组织炎症反应”和“HIF-1α-VEGF-肺血管通透性-肺水肿”两条路径加重肺组织炎症反应、肺血管通透性和肺水肿,导致肺损伤。

Objective To explore the role of HIF-1αin PM_(2.5)-induced lung injury.Methods The rat model of lung injury induced by tracheal aerosol PM_(2.5)suspension was established,HIF-1αexpression and lung injury under different PM_(2.5)exposure doses were investigated by western blot,pathological section,ROS staining,TUNEL staining and ELISA.An animal model was constructed to inhibit HIF-1αexpression,and the mechanism of HIF-1αin lung injury induced by PM_(2.5)exposure was investigated by western blot,immunofluorescence and ELISA.Results PM_(2.5)exposure causes pathological damage,increases ROS level,apoptosis rate and wet-dry ratio of lung tissue,promotes the count of various inflammatory cells and the levels of inflammatory factors IL-6 and TNF-αin BALF,and activates the protein expression of HIF-1αin lung tissue,the above effects are related to PM_(2.5)exposure concentration.Inhibition of HIF-1αcan reduce lung inflammation by decreasing NF-κB expression in lung tissue and the level of inflammatory factors in BALF.Inhibition of HIF-1αcan reduce lung tissue edema by decreasing VEGF expression in lung tissue,albumin level in BALF and lung tissue wet-dry ratio.Conclusion PM_(2.5)aggravates lung tissue inflammation,pulmonary vascular permeability and pulmonary edema by activating two pathways:HIF-1α-NF-κB-inflammatory cells(AMs,NEUs)/inflammatory factors(IL-6,TNF-α)-lung tissue inflammation and HIF-1α-VEGF-pulmonary vascular permeability-pulmonary edema.