在患有急性肺损伤的小猪的肺泡巨噬细胞中一氧化氮，表面活性剂和糖皮质激素对核因子-κB和激活蛋白-1的活性的调控作用

AIM： To investigate whether acute lung injury (ALI) in ventilated piglets with bacterial infection affects NF-κB and AP-1 expression in alveolar macrophages (AM) and whether nitric oxide (NO), surfactant (Surf), glucocorticoids (GC) affect NF-κB and AP-1 activation in AM in vivo and in vitro. METHODS: The animals were intraperitoneally injected Escherichia coli, which caused ALI. Nuclear extracts of AM were analyzed by electrophoretic mobility shift assay (EMSA) for the nuclear factor-kappa B (NF-κB) and activation protein-1 (AP-1) expression. Detection of IκB-α protein was from cytoplasmic extract by Western blotting. Immunocytochemistry staining was used for intracellular location of p65 subunits of NF-κB. RESULTS: In ex vivo experiments, strikingly higher expression of NF-κB and AP-1 by EMSA was found 6h after bacterial injection in contrast to the Normal group. In the NO, SNO,and GC groups, markedly attenuated NF-κB and AP-1 activation was observed. The NF-κB and AP-1 activation in Surf group showed lower levels of the expression. Immunoblotting of AM cytoplasmic extract showed low expression of IκB-α protein in the Control and Surf groups. The stronger expression was observed in the NO, GC,and SNO groups. AM of the Control and Surf groups showed intense nuclear staining, with decreased nuclear staining in the NO, GC and SNO groups. In in vitro experiment, it caused a significant increase in NF-κB and AP1 activity in AM 1h after exposure to lipopolysaccharides (LPS). In AM treated by LPS SNP and LPS GC, all showed decrease of DNA binding activity of NF-κB and AP-1 compared to those exposed to LPS Surf. Immunoblotting of AM cytoplasmic extract showed that LPS stimulation of AM resulted in the low expression of IκB-α protein, which was not observed in the presence of SNP and methylprednisolone. However, the surfact antdid not show such effect. LPS Surf-exposed AM had intense nuclear staining, whereas decreased nuclear staining in the LPS NO and LPS GC-treated cultures was found, confirming a decrease in NF-rd3 activity. CONCLUSION:Activation of NF-κB was found in AM of ventilated piglets with bacterial ALI. NO and GS could prevent NF-κB and AP-1 activation in vivo and in vitro. Surfactant has limited effects on NF-κB and AP-1 activity.

Regulation of activity of nuclear factor-kappaB and activator protein-1 by nitric oxide, surfactant and glucocorticoids in alveolar macrophages from piglets with acute lung injury

AIM: To investigate whether acute lung injury (ALI) in ventilated piglets with bacterial infection affects NF-kappaB and AP-1 expression in alveolar macrophages (AM) and whether nitric oxide (NO), surfactant (Surf), glucocorticoids (GC) affect NF-kappaB and AP-1 activation in AM in vivo and in vitro. METHODS: The animals were intraperitoneally injected Escherichia coli, which caused ALI. Nuclear extracts of AM were analyzed by electrophoretic mobility shift assay (EMSA) for the nuclear factor-kappa B (NF-kappaB) and activation protein-1 (AP-1) expression. Detection of IkappaB-alpha protein was from cytoplasmic extract by Western blotting. Immunocytochemistry staining was used for intracellular location of p65 subunits of NF-kappaB. RESULTS: In ex vivo experiments, strikingly higher expression of NF-kappaB and AP-1 by EMSA was found 6 h after bacterial injection in contrast to the Normal group. In the NO, SNO, and GC groups, markedly attenuated NF-kappaB and AP-1 activation was observed. The NF-kappaB and AP-1 activation in Surf group showed lower levels of the expression. Immunoblotting of AM cytoplasmic extract showed low expression of IkappaB-alphaprotein in the Control and Surf groups. The stronger expression was observed in the NO, GC, and SNO groups. AM of the Control and Surf groups showed intense nuclear staining, with decreased nuclear staining in the NO, GC and SNO groups. In in vitro experiment, it caused a significant increase in NF-kappaB and AP-1 activity in AM 1 h after exposure to lipopolysaccharides (LPS). In AM treated by LPS+SNP and LPS+GC, all showed decrease of DNA binding activity of NF-kappaB and AP-1 compared to those exposed to LPS+Surf. Immunoblotting of AM cytoplasmic extract showed that LPS stimulation of AM resulted in the low expression of IkappaB-alpha protein, which was not observed in the presence of SNP and methylprednisolone. However, the surfactant did not show such effect. LPS+Surf-exposed AM had intense nuclear staining, whereas decreased nuclear staining in the LPS+NO and LPS+GC-treated cultures was found, confirming a decrease in NF-kappaB activity. CONCLUSION:Activation of NF-kappaB was found in AM of ventilated piglets with bacterial ALI. NO and GS could prevent NF-kappaB and AP-1 activation in vivo and in vitro. Surfactant has limited effects on NF-kappaB and AP-1 activity.