Objective To investigate the effects of IL-10 on lipopolysaccharide( LPS) -induced MyD88 /NF-κB signaling activation. Methods Ana-1 macrophages were divided into a LPS group and a LPS + IL-10 group. The cells and the culture supernatant were collected at 0, 0. 5, 1, and 2 hours respectively. The expression levels of NF-κB p65 and MyD88 in cytoplasm and nucleus were detected by Western blotting. The concentration of TNF-αin the culture supernatant was determined by ELISA. Results Through 0 to 2 hours, MyD88 expression increased significantly after LPS stimulation. The expression was attenuated by the pretreatment of IL-10, which returned to normal levels at 2 hours( 8. 8 ±0. 3 vs 21. 4 ±1. 8,P lt;0. 05) . IL-10 had no effect on total expression of NF-κB, but decreased nuclei / cytoplasm ratio of NF-κB p65 after LPS stimulation. The ratio was lower in the LPS + IL-10 group compared and the LPS group at 1 hour and 2 hour ( 1. 1 ±0. 1 vs 2. 4 ±0. 4, 0. 6 ±0. 7 vs 3. 1 ±0. 6, P lt; 0. 05) . Consequently, IL-10 pretreatment decreased TNF-α concentration after LPS stimulation at 1 hour and 2 hours [ ( 222. 5 ±33. 5) pg/mL vs ( 365. 2 ±22. 7) pg/mL, ( 212. 7 ±15. 9) pg/mL vs ( 566. 2 ±31. 5) pg/mL, P lt;0. 05] .Conclusion IL-10 attenuates inflammation via MyD88 /NF-κB signal pathway depression.
Objective To evaluate the effects of two different epidermal growth factor receptor tyrosine kinase inhibitors ( EGFR-TKIs) , Gefitinib and Erlotinib, on lung fibrosis induced by bleomycin.Methods Forty BALB/c female mice were randomly divided into four groups, ie. a control group( saline given orally and intratracheally) , a fibrosis group( saline given orally with bleomycin instillation) , a Gefitnib group( Gefitnib 20 mg/kg given orally with bleomycin instillation) , and an Erlotinib group ( Erlotinib25 mg/kg given orally with bleomycin instillation) . Bleomycin ( 3 mg/kg) was intratracheally instilled on the first day. Gefitinib or Erlotinib was given orally daily and normal saline as control. Then they were sacrificed by abdominal aortic bleeding 14 days after the bleomycin instillation. The left lung was stained with HE and Masson’s trichrome staining respectively for pathological examination. Total EGFR and phosphorylated EGFR were detected by immunohistochemistry. Hydroxyproline ( HYP) assay was performed in the right lung.Results Both Gefitinib and Erlotinib significantly reduced lung collagen accumulation and the content of HYP. Immunohistochemistry revealed that phosphorylation of EGFR in lung mesenchymal cells induced by bleomycin was inhibited. Furthermore, there was no difference between Gefitinib and Erlotinib in inhibiting lung fibrosis. Conclusion Our findings suggest that, in the preclinical setting, EGFR-TKIs may have aprotective effect on lung fibrosis induced by bleomycin.
Objective To establish a cell culture model in vitro of acute lung injury and investigate the effects of NF-κB p65 on the inflammation and oxidative stress in TNF-α-activated type Ⅱ alveolar epithelial cells. Methods A549 cells were treated with TNF-α ( 10 ng/mL, 24 h) in the absence or presence of NF-κB p65 siRNA ( 50 nmol /L) . RT-PCR and Western blot were performed to analyze the silence efficiency of RNAi targeting NF-κB p65. The contents of IL-1β, IL-4, and IL-6 in the culture supernatant were measured by ELISA. The concentration of MDA and SOD were detected by colorimetric method. The survival rate of cell was assessed by the methyl thiazolyl tetrazolium ( MTT) assay. Results P65 RNAi significantly decreased the transcription and translation of NF-κB p65 induced by TNF-α( P lt; 0. 05) . The levels of IL-1β, IL-4, and IL-6 were significantly lower in the supernatants of A549 cells pretransfected with NF-κB p65 siRNA ( P lt;0. 05) , while the concentration of MDA markedly decreased ( P lt; 0. 05) , and the activation of SOD increased dramatically ( P lt; 0. 05) . Consequently, the survival rate of A549 in the p65 siRNA group improved( P lt; 0. 05) . Conclusions NF-κB p65 plays a key role in the oxidative stress induced by TNF-α. NF-κB p65 silencing can down-regulate the inflammation and oxidative stress induced by TNF-αand enhance the proliferation of alveolar epithelial cells.
Objective To compare three approaches of lipopolysaccharides ( LPS) administration for inducing acute lung injury ( ALI) in mice. Methods LPS ( 5 mg/kg) was intratracheally aerosol administered ( ITA group) , intratracheally instilled ( ITI group) , or intraperitoneally injected ( IPI group) to induce ALI in BLAB/ c mice. Evans Blue instead of LPS was intratracheally administered to observe the liquid distribution in the lungs. Two hours after LPS administration, the mice were sacrificed and the lungs were removed to determine wet-to-dry lung weight ratio ( W/D) , and the histological changes were evaluated by HE staining. Phosphorylation level of IκB-αand NF-κB p65 in lung tissue were investigated by Western blot. Transcription intensity of TNF-α and IL-1β mRNA in lung tissue were detected by real-time quantitative PCR. Results Evans Blue distributed more uniformly in the ITA group than the ITI group. The lung W/D ratio and histological changes score in three LPS administration groups were all significantly higher than the normal control group ( P lt;0. 01) , with the ITA group being the highest. The phosphorylation levels of IκB-αand NF-κB p65 were significantly higher in the ITA group than the ITI group ( P lt;0. 05) , and were significantly higher in the ITI group than the IPI group ( P lt; 0. 05) . Transcription intensity of TNF-αand IL-1βmRNA was significantly higher in the ITA group than the ITI group ( P lt;0. 05) , and were significantly higher in the ITI group than the IPI group ( P lt;0. 05) . Conclusion Being non-invasive and convenient,intratracheal LPS aerosol inhalation is an optimal method to induce ALI in mice because it induces more extensive and uniformly distributed injuries in lung.
Objective To investigate the role of alveolar macrophages ( AMs ) in airway inflammation of smoke-induced COPD rat model and its possible regulating mechanism. Methods Twelve Wistar rats were randomly divided into a COPD group and a control group. The rat model of COPD was established with smoke exposure and LPS intrathacheal instillation. Bronchoalveolar lavage fluid ( BALF)was collected for measurement of total and differential cell counts. Then AMs were isolated and identified byimmunofluorescence. Western blot was employed to analyze the cytoplasmic and nuclear NF-κB p65 expression of AMs. The concentrations of TNF-α,macrophage inflammatory protein 2 ( MIP-2) and IL-10 in cell culture supernatantwere assayed by ELISA.Results The scores of bronchitis and mean liner intercepts in the COPD group were significantly higher than those in the control group [ 4. 33 ±1. 16 vs. 1. 33 ±0. 58,P =0. 016; ( 168. 77 ±11. 35) μm vs. ( 93. 61 ±4. 16) μm, P = 0. 000) ] . The total cell count in BALF of the COPD group was significantly higher than that in the control group ( P lt; 0. 05) , and the AMs and neutrophils were predominant [ ( 72. 00 ±2. 22) % and ( 18. 29 ±8. 34) % ] . The cytoplasmic NF-κB p65 expression of AMs in the COPD group was significantly lower , while the nuclear NF-κB p65 expression was significantly higher ( P lt; 0. 05) compared with the control group. The ELISA results showed that the concentrations of TNF-αand MIP-2 in culture supernatant of AMs in the COPD group were significantly higher than those in the control group ( P lt;0. 05) , while the concentration of IL-10 was not significantly different between the two groups ( P gt;0. 05) . Conclusions COPD rat model was established successfully with smoke exposure and LPS intratracheal instillation with a profile of macrophage-based chronic inflammation and increased secretion of TNF-αand MIP-2. The mechanismis closely related to activation of NF-κB.
ObjectiveTo compare two different ways to establish mouse model with acute lung injury (ALI) via intratracheal instillation or intraperitoneal injection of lipopolysaccharide (LPS). MethodsBALB/c mice received intraperitoneal/intratracheal administration of LPS or sham operation. Wet/dry lung weight ratio, protein concentration in bronchoalveolar lavage fluid (BALF), and lung tissue histology were examined at 0, 1, 2, 6, 12, 18, 24, 48 h after LPS administration. Tumor necrosis factor-α (TNF-α) in BALF and serum was assayed with ELISA method. ResultsLPS treatment significantly increased wet/dry lung weight ratio, BALF protein concentration and TNF-α concentration in serum and BALF. Lung tissue was damaged after LPS challenge. The mice received LPS intraperitoneal injection got a more significant lung edema than those received LPS intratracheal instillation. Inversely, LPS intratracheal instillation induced more severed microstructure destruction. ConclusionsALI animal model by LPS intratracheal instillation or intraperitoneal injection induces inflammation and tissue damage in lung. However, the degree of tissue damage or self-healing induced by two methods is different. Therefore the decision of which way to establish ALI model will depend on the study purpose.
ObjectiveTo establish 16HBE cell lines stably expressing glutathione S-transferase mu 5 (GSTM5) gene, and explore the mechanism of GSTM5 nuclear translocation. MethodsRecombinant lentiviral expression vector containing GSTM5 gene was constructed and lentivirus was produced. After lentivirus infection of 16HBE cells, 16HBE-GSTM5 cell lines were obtained by screening with puromycin. Expression of GSTM5 in different cells was examined by RT-qPCR and Western blot. The nuclear translocation of GSTM5 was observed by confocal laser scanning microscope, after the 16HBE-GSTM5 cell lines were treated with tumor necrosis factor-α (TNF-α; 10 ng/ml) for 0.5 hour. ResultsLentiviral expression plasmids, PLVX-puro-3*flag-SBP-GSTM5-C and PLVX-puro-GSTM5-SBP-3*flag-N, were constructed and lentiviral particles were successfully packed. After infected with lentivirus and screened by puromycin, two cell lines, 16HBE-GSTM5-SBP-3*flag-N and 16HBE-3*flag-SBP-GSTM5-C, were obtained. GSTM5 expression in these two cell lines was significantly higher compared with the control group and parental cells. After treated with TNF-α for 0.5 hour, the nuclear translocation of GSTM5 in 16HBE-GSTM5-SBP-3*flag-N was much more obviously than that in 16HBE-3*flag-SBP-GSTM5-C. ConclusionThe N-terminal region of GSTM5 is critical for nuclear translocation induced by TNF-α, which is mediated by a novel and non-classical nuclear localization signal.