摘要目的:探讨分子氢对脂多糖（lipopolysaccharide, LPS）诱导急性肺损伤（acute lung injury, ALI）的作用机制。方法:将24只Balb/c小鼠随机（随机数字法）分为4组：control组、control+H 2组、LPS组、LPS+H 2组，6只/组。观察各组肺组织形态，检测肺组织丙二醛（malondialdehyde, MDA）、Fe 2+水平，对肺组织进行免疫荧光染色检测F4/80阳性巨噬细胞浸润水平。将A549细胞分为control、control+H 2、erastin、erastin+H 2组，检测各组活性氧自由基（reactive oxygen species，ROS）、丙二醛（malondialdehyde, MDA）、谷胱甘肽（glutathione, GSH）、细胞死亡数量、乳酸脱氢酶（lactate dehydrogenase, LDH）释放量，荧光定量PCR定量核因子红细胞2相关因子2（nuclear factor erythroid 2-related factor 2, Nrf2）、谷胱甘肽过氧化物酶4（glutathione peroxidase 4, GPX4）、血红素氧化酶1（heme oxygenase-1, HO-1）mRNA表达水平，蛋白质免疫印迹检测Nrf2蛋白表达水平，免疫荧光法检测Nrf2核转位水平。计量资料统计前进行方差齐性检验，多组间差异比较采用单因素方差分析。 结果:与control组比较，LPS组肺组织损伤明显加重，F4/80阳性巨噬细胞浸润程度、脂质过氧化水平增高（均 P<0.05）；与LPS组比较，LPS+H 2组肺损伤程度明显减轻（均 P<0.05）；体外实验中，与control组比较，erastin组ROS、MDA水平、细胞死亡数量、LDH释放量增多（均 P<0.05），GSH、GPX4 mRNA水平下降，HO-1 mRNA、Nrf2核转位水平增高（均 P<0.05），与erastin组相比，earstin+H 2组ROS、MDA水平、细胞死亡数量、LDH释放量下降（均 P<0.05），GSH、GPX4 mRNA、Nrf2 mRNA 、HO-1 mRNA水平提高，Nrf2核转位水平升高（均 P<0.05）。 结论:分子氢促进Nrf2核转位，抑制肺泡上皮细胞铁死亡减轻LPS诱导的ALI。

abstractsObjective:To investigate the role and mechanism of molecular hydrogen in lipopolysaccharide (LPS)-induced acute lung injury (ALI).Methods:Balb/c male mice were randomly(random number) divided into control group, control+H 2, LPS and LPS+H 2 group with 6 mice in each group. The levels of malondialdehyde (MDA) and Fe 2+ in lung tissue were detected by kits. The lung tissue morphology was observed. The infiltration levels of F4/80 positive macrophages in lung tissue were detected by immunofluorescence staining. A549 cells were divided into control, control+H 2, erastin and erastin+H 2 group. The reactive oxygen species (ROS), malondialdehyde, (MDA), lactate dehydrogenase (GSH), number of cell death and lactate dehydrogenase (LDH) release in each group were detected by kits. Nrf2, GPX4, and HO-1mRNA were quantified by real-time PCR, the protein expression level of Nrf2 was detected by western blot, and the nuclear translocation level of Nrf2 was observed by immunofluorescence. The chi-square test was performed before the measurement data were counted. One-way analysis of variance was used to compare differences between multiple groups. Results:Compared with the control group, the histopathological damage was aggravated, and the levels of MDA, Fe 2+ significantly increased in the LPS group, and F4/80 positive immune cells infiltration significantly increased (all P<0.05). Compared with LPS group, the degree of lung injury in LPS+H 2 group significantly reduced (all P<0.05). In vitro experiments, compared with the control group, the ROS, MDA levels, number of cell death and LDH release significantly increased in erastin group (all P<0.05), while GSH, and GPX4 mRNA levels decreased (all P<0.05). HO-1mRNA and Nrf2 nuclear translocation levels increased (all P<0.05). Compared with erastin group, ROS, MDA levels, cell death number and LDH release decreased in earstin+H 2 group (all P<0.05). The levels of GSH, GPX4 mRNA, Nrf2 mRNA, HO-1 mRNA and Nrf2 nuclear translocation levels increased (all P<0.05). Conclusions:Molecular hydrogen attenuates LPS-induced ALI by promoting Nrf2 nuclear translocation to inhibit ferroptosis of alveolar epithelial cells.