Background Acute lung injury （ALl） is a serious and common condition for which there are currently no specific strategies for treatment. Recent studies have suggested that bone marrow-derived multipotent mesenchymal...Background Acute lung injury （ALl） is a serious and common condition for which there are currently no specific strategies for treatment. Recent studies have suggested that bone marrow-derived multipotent mesenchymal stem cells （MSCs） may have therapeutic applications in multiple clinical disorders. We explored the biological effects of MSCs during endotoxin-induced ALl and the mechanisms involved. Methods MSCs were isolated from male rat bone marrow and the ALl model was induced by intravenous endotoxin injection. Female rats were sacrificed at 6 hours, 24 hours, 4 days, 1 week and 3 weeks post-injection of MSCs or saline and the lung tissue, bronchoalveolar lavage fluid, and serum were harvested for analysis. We further evaluated the survival of the rats and examined the effects of endotoxin-induced injury on the interaction between alveolar macrophages （AMs） and MSCs in ex vivo. Results There was a significant decrease in numbers of neutrophils in bronchoalveolar lavage fluid （P 〈0.05）, and myeloperoxidase activity in the lung （P 〈0.01）, and of TNF-α and IL-1β in serum （P 〈0.05） in the MSC treated rats at 4 days. Furthermore, MSC treated rats exhibited improved survival, lower lung injury score, higher concentration of IL-10 in the serum and a reduced hydroxyproline content, but these differences were not statistically significant. Moreover, co-cultures of MSCs and AMs had significantly reduced levels of TNF-α, IL-1β and macrophage inflammatory protein （MIP）-1α and significantly increased levels of IL-10 （P〈0.05） in the culture supernatants. Conclusions Treatment with intravenous injection of bone marrow-derived MSCs have beneficial effects on endotoxin-induced ALl in rats. The beneficial effect might be achieved through the engraftment of differentiated MSCs in the lungs and appears derive more from their capacity to secrete soluble factors that modulate immune responses.展开更多
Background Toll-like receptor-4 （TLR-4） is integrally involved in lipopolysaccharide （LPS） signaling and has a requisite role in the activation of nuclear factor-κB （NF-κB）. The exact mechanisms that lend perf...Background Toll-like receptor-4 （TLR-4） is integrally involved in lipopolysaccharide （LPS） signaling and has a requisite role in the activation of nuclear factor-κB （NF-κB）. The exact mechanisms that lend perfluorocarbon （PFC） liquids a cytoprotective effect have yet to be elucidated. Therefore we examined in an in vitro model the cytoprotective effect of PFC on LPS-stimulated alveolar epithelial cellls （AECs）. Methods AECs （A549 cells, human lung adenocarcinoma cell line） were divided into four groups： control, PFC, LPS and LPS ＋ PFC （coculture group） groups. Intercellular adhesion molecule-1 （ICAM-1） was detected by ELISA, tumor necrosis factor-g （TNF-a） and interleukin-8 （IL-8） were detected by radioimmunological methods. The expression of TLR-4 mRNA and protein was detected by real time PCR and Western blotting, respectively. The activation of NF-κB was detected by Western blotting （proteins of I-κBa and NF-κB p65）. Results ICAM-1, TNF-a and IL-8 were significantly increased in LPS-stimulated AECs groups. The expression of TLR-4 mRNA and protein in LPS-stimulated groups was markedly increased. Meanwhile, NF-κB was activated as indicated by the significant degradation of IKB-a and the significant release of NF-κB P65 and its subsequent translocation into the nucleus. There were no significant effects of PFC alone on any of the factors studied while the coculture group showed significant downregulation of the secretion of ICAM-1, TNF-a and IL-8, the expression of TLR-4 rn^NA and the activity of NF-κB. Conclusions Taken together, our results demonstrate that LPS can induce AEC-related inflammatory injury via the activation of TLR-4 and subsequent activation of NF-κB. PFC is able to protect AECs from LPS-induced inflammatory injury by blocking the initiation of the LPS signaling pathway, which is indicated by the significant decrease of TLR-4 expression and NF-κB activation.展开更多
Background Gefitinib, an inhibitor of epidermal growth factor receptor （EGFR） tyrosine kinase, is an effective treatment for epithelial tumors, including non-small cell lung cancer （NSCLC）, and is generally well t...Background Gefitinib, an inhibitor of epidermal growth factor receptor （EGFR） tyrosine kinase, is an effective treatment for epithelial tumors, including non-small cell lung cancer （NSCLC）, and is generally well tolerated.However, some clinical trials revealed that gefitinib exposure caused lung fibrosis, a severe adverse reaction.This study investigated the effect of gefitinib on lung fibrosis in mice.Methods We generated a mouse model of lung fibrosis induced by bleomycin to investigate the fibrotic effect of gefitinib.C57BL/6 mice were injected intratracheally with bleomycin or saline, with intragastric administration of gefitinib or saline.Lung tissues were harvested on day 14 or 21 for histology and genetic analysis.Results The histological results showed that bleomycin successfully induced lung fibrosis in mice, and gefitinib prevented lung fibrosis and suppressed the proliferation of S100A4-positive fibroblast cells.In addition, Western blotting analysis revealed that gefitinib decreased the expression of phosphorylated EGFR （p-EGFR）.Furthermore, quantitative real-time PCR （qRT-PCR） demonstrated that gefitinib inhibited the accumulation of collagens Ⅰ and Ⅲ.Conclusions These results reveal that gefitinib reduces pulmonary fibrosis induced by bleomycin in mice and suggest that administration of small molecule EGFR tyrosine kinase inhibitors has the potential to prevent pulmonary fibrosis by inhibiting the proliferation of mesenchymal cells, and that targeting tyrosine kinase receptors might be useful for the treatment of pulmonary fibrosis in humans.展开更多
文摘Background Acute lung injury （ALl） is a serious and common condition for which there are currently no specific strategies for treatment. Recent studies have suggested that bone marrow-derived multipotent mesenchymal stem cells （MSCs） may have therapeutic applications in multiple clinical disorders. We explored the biological effects of MSCs during endotoxin-induced ALl and the mechanisms involved. Methods MSCs were isolated from male rat bone marrow and the ALl model was induced by intravenous endotoxin injection. Female rats were sacrificed at 6 hours, 24 hours, 4 days, 1 week and 3 weeks post-injection of MSCs or saline and the lung tissue, bronchoalveolar lavage fluid, and serum were harvested for analysis. We further evaluated the survival of the rats and examined the effects of endotoxin-induced injury on the interaction between alveolar macrophages （AMs） and MSCs in ex vivo. Results There was a significant decrease in numbers of neutrophils in bronchoalveolar lavage fluid （P 〈0.05）, and myeloperoxidase activity in the lung （P 〈0.01）, and of TNF-α and IL-1β in serum （P 〈0.05） in the MSC treated rats at 4 days. Furthermore, MSC treated rats exhibited improved survival, lower lung injury score, higher concentration of IL-10 in the serum and a reduced hydroxyproline content, but these differences were not statistically significant. Moreover, co-cultures of MSCs and AMs had significantly reduced levels of TNF-α, IL-1β and macrophage inflammatory protein （MIP）-1α and significantly increased levels of IL-10 （P〈0.05） in the culture supernatants. Conclusions Treatment with intravenous injection of bone marrow-derived MSCs have beneficial effects on endotoxin-induced ALl in rats. The beneficial effect might be achieved through the engraftment of differentiated MSCs in the lungs and appears derive more from their capacity to secrete soluble factors that modulate immune responses.
文摘Background Toll-like receptor-4 （TLR-4） is integrally involved in lipopolysaccharide （LPS） signaling and has a requisite role in the activation of nuclear factor-κB （NF-κB）. The exact mechanisms that lend perfluorocarbon （PFC） liquids a cytoprotective effect have yet to be elucidated. Therefore we examined in an in vitro model the cytoprotective effect of PFC on LPS-stimulated alveolar epithelial cellls （AECs）. Methods AECs （A549 cells, human lung adenocarcinoma cell line） were divided into four groups： control, PFC, LPS and LPS ＋ PFC （coculture group） groups. Intercellular adhesion molecule-1 （ICAM-1） was detected by ELISA, tumor necrosis factor-g （TNF-a） and interleukin-8 （IL-8） were detected by radioimmunological methods. The expression of TLR-4 mRNA and protein was detected by real time PCR and Western blotting, respectively. The activation of NF-κB was detected by Western blotting （proteins of I-κBa and NF-κB p65）. Results ICAM-1, TNF-a and IL-8 were significantly increased in LPS-stimulated AECs groups. The expression of TLR-4 mRNA and protein in LPS-stimulated groups was markedly increased. Meanwhile, NF-κB was activated as indicated by the significant degradation of IKB-a and the significant release of NF-κB P65 and its subsequent translocation into the nucleus. There were no significant effects of PFC alone on any of the factors studied while the coculture group showed significant downregulation of the secretion of ICAM-1, TNF-a and IL-8, the expression of TLR-4 rn^NA and the activity of NF-κB. Conclusions Taken together, our results demonstrate that LPS can induce AEC-related inflammatory injury via the activation of TLR-4 and subsequent activation of NF-κB. PFC is able to protect AECs from LPS-induced inflammatory injury by blocking the initiation of the LPS signaling pathway, which is indicated by the significant decrease of TLR-4 expression and NF-κB activation.
基金This study was supported by grants from National Natural Science Foundation of China （No.30370616 and No.30070335）, and Eleventh Five-Year Project of the Armed Forces Outstanding Talent （No.06J019）.
文摘Background Gefitinib, an inhibitor of epidermal growth factor receptor （EGFR） tyrosine kinase, is an effective treatment for epithelial tumors, including non-small cell lung cancer （NSCLC）, and is generally well tolerated.However, some clinical trials revealed that gefitinib exposure caused lung fibrosis, a severe adverse reaction.This study investigated the effect of gefitinib on lung fibrosis in mice.Methods We generated a mouse model of lung fibrosis induced by bleomycin to investigate the fibrotic effect of gefitinib.C57BL/6 mice were injected intratracheally with bleomycin or saline, with intragastric administration of gefitinib or saline.Lung tissues were harvested on day 14 or 21 for histology and genetic analysis.Results The histological results showed that bleomycin successfully induced lung fibrosis in mice, and gefitinib prevented lung fibrosis and suppressed the proliferation of S100A4-positive fibroblast cells.In addition, Western blotting analysis revealed that gefitinib decreased the expression of phosphorylated EGFR （p-EGFR）.Furthermore, quantitative real-time PCR （qRT-PCR） demonstrated that gefitinib inhibited the accumulation of collagens Ⅰ and Ⅲ.Conclusions These results reveal that gefitinib reduces pulmonary fibrosis induced by bleomycin in mice and suggest that administration of small molecule EGFR tyrosine kinase inhibitors has the potential to prevent pulmonary fibrosis by inhibiting the proliferation of mesenchymal cells, and that targeting tyrosine kinase receptors might be useful for the treatment of pulmonary fibrosis in humans.
