OBJECTIVETo investigate the effect of losartan in regulating oxidative stress and the underlying mechanism in mice with ventilator-induced lung injury.

METHODSThirty-six male C57 mice were randomly divided into control group, losartan treatment group, mechanical ventilation model group, and ventilation plus losartan treatment group. After the corresponding treatments, the lung injuries in each group were examined and the expressions of caveolin-1 and NOX4 in the lung tissues were detected.

RESULTSThe mean Smith score of lung injury was significantly higher in mechanical ventilation model group (3.3) than in the control group (0.4), and losartan treatment group (0.3); the mean score was significantly lowered in ventilation plus losartan treatment group (2.3) compared with that in the model group (P<0.05). The expressions of caveolin-1 and NOX4 were significantly higher in the model group than in the control and losartan treatment groups (P<0.05) but was obviously lowered after losartan treatment (P<0.05). Co-expression of caveolin-1 and NOX4 in the lungs was observed in the model group, and was significantly decreased after losartan treatment.

CONCLUSIONLosartan can alleviate ventilator-induced lung injury in mice and inhibit the expression of caveolin-1 and NOX4 and their interaction in the lungs.

Animals ; Caveolin 1 ; metabolism ; Losartan ; pharmacology ; Lung ; metabolism ; physiopathology ; Male ; Mice ; Mice, Inbred C57BL ; NADPH Oxidase 4 ; NADPH Oxidases ; metabolism ; Oxidative Stress ; Respiration, Artificial ; Ventilator-Induced Lung Injury ; drug therapy ; metabolism

OBJECTIVE: To observe the effect of exosomes secreted by lipopolysaccharides (LPS)-stimulated macrophages on hepatic stellate cell activation and migration and explore the underlying molecular mechanism. METHODS: Human monocyte THP-1 cells were induced to differentiate into macrophages using propylene glycol methyl ether acetic acid (PMA, 100 ng/mL, 24 h) followed by stimulation with LPS, and the culture supernatant of macrophages was collected for extraction of the exosomes by ultracentrifugation. The expression of miR-155-5p in the exosomes was detected using qRT-PCR. A Transwell co-culture system was used to observe the effects of the macrophage-derived exosomes on LX2 cell (a hepatic stellate cell line) proliferation, migration, oxidative stress and the expression of fibrosis biomarkers, which were also observed in LX2 cells transfected with miR-155-5p-mimics or miR-155-5p-inhibitors. Western blotting was used to detect the expressions of SOCS1 and its downstream signal pathway proteins. RESULTS: Treatment with the exosomes from LPS-stimulated macrophages significantly enhanced the proliferation and migration ability of LX2 cells and increased the levels of oxidative stress and expressions of the fibrosis markers such as type Ⅰ collagen (P < 0.05). The expression of miR-155-5p in the exosomes secreted by macrophages was significantly increased after LPS treatment (P < 0.01). LX2 cells overexpressing miR-155-5p also exhibited significantly enhanced proliferation and migration with increased oxidative stress levels and expression of type Ⅰ collagen (P < 0.05), and interference of miR-155-5p expression produced the opposite effects. Western blotting showed that miR-155-5p overexpression obviously inhibited SOCS1 expression and promoted p-Smad2/3, Smad2/3 and RhoA protein expressions in LX2 cells (P < 0.05). CONCLUSION LPS stimulation of the macrophages increases miR-155-5p expression in the exosomes to promote activation and migration and increase oxidative stress and collagen production in hepatic stellate cells.
Humans ; Hepatic Stellate Cells ; Lipopolysaccharides/pharmacology* ; Collagen Type I ; Exosomes ; Macrophages ; MicroRNAs