The effect of extracellular signal-regulated kinase 1/2 signaling pathway on the expression of transforming growth factor-beta1 in lung fibroblast activated by silicon dioxide / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect and regulation of extracellular signal-regulated kinase (ERK1/2) signaling pathway on the expression of transforming growth factor-beta1 (TGF-beta1) in human embryonic lung fibroblasts induced by SiO2.</p><p><b>METHODS</b>Human alveolar macrophages were collected from a silicotic patient by bronchoalveolar lavage and in the presence or absence of SiO2 (50 ug/ml) exposition for 18h, and then the conditioned supernatants were used to incubate HELF. The expressions of TGF-beta1, of the HELF acted with the conditioned AM supernatant fluid were detected with the immunocytochemistry method after treatment with PD98059 of inhibitor of ERK.</p><p><b>RESULTS</b>The expression of TGF-beta1 in HELF of the SiO2 treatment group (OD value is 0.322 7 +/- 0.023 8) exceed blank group (OD value is 0.163 7 +/- 0.019 6) and AM control group (OD value is 0.240 6 +/- 0.022 5) by the immunocytochemistry method. But the expression of TGF-beta1 had reduction in some extent in the PD98059 intervention group (OD value is 0.271 1 +/- 0.022 9). The values were statistically different (P < 0.05).</p><p><b>CONCLUSION</b>ERK inhibitor PD98059 have inhibition effect on the expression of transforming growth factor-beta1 and expression of cytokine of human embryonic lung fibroblasts stimulated by SiO2. The study indicate that the proliferation and collagen production of HELF activated by SiO2 are mediated by ERK/MAPK signal pathway in some extent. PD98059 may antagonizes silica-induced lung fibrosis by inhibiting the expression of transforming growth factor-beta1.</p>

Effect of ERK1/2 signal pathway on the proliferation of lung fibroblast activated by SiO₂ / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To observe the effect of ERK1/2 signal pathway activated by SiO₂ in the proliferation of human embryonic lung fibroblast mediated by silicotic alveolar macrophages.</p><p><b>METHOD</b>The alveolar macrophages (AM) harvested from silicotic sufferers by bronchoalveolar lavage (BAL) were interacted with SiO₂ suspension once more. HELF, pretreated with the inhibitor PD98059 (50 µmol/L) for 1 hour, were stimulated by conditional supernatant fluid of silicotic sufferers. The experimentation have been classificated four group: blank group, AM control group, SiO₂ treatment group, PD98059 intervention group. The proliferation activity and expressions of Phospho-ERK1/2 of lung fibroblast activated by AM supernatant fluids of silicotic are detected with the MTT assay, flow cytometry and Western blot method after being pretreatmented with PD98059.</p><p><b>RESULT</b>The A values of cell proliferation in SiO₂ treatment group and AM control group are 2.6 and 2.0 times that of blank group, in which the difference was statistically significant (P < 0.05). Comparing with SiO₂ treatment group, the A values of every concentrations of PD98059 intervention group decreased with a dose-response relationship, after 10, 25 and 50 µmol/L PD98059 intervention. The 25 and 50 µmol/L PD98059 intervention group were 72.1% and 48.5% of SiO₂ treatment group, which the difference is statistic (P < 0.05). The expression of phospho-ERK1/2 in SiO₂ treatment group was up, which appeared in 15 min and apparent activated in 30 min (A value is 0.4653 ± 0.0265), and then still in the higher state afterwards declined after 60 min. In addition to 15 min, the expression of phospho-ERK1/2 protein in SiO₂ treatment group at each time point are 1.25, 1.23, 1.25 times over the same period AM control group respectively, the differences were statistically significant (P < 0.05).</p><p><b>CONCLUSION</b>The silicotic supernatant of alveolar macrophages have promote proliferation of HELF and activation of ERK1/2, which may involve in the development of silicosis pathogenesis by ERK1/2 signal pathway.</p>

Effect of p38MAPK on proliferation in human embryonic lung fibroblasts in vitro / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the proliferation effect of the AM supernatant incubated activation of p38 mitogen activated protein kinases (p38MAPK) signal transduction pathway in human embryonic lung fibroblasts, and to participate in the development of fibrosis in silicosis.</p><p><b>METHODS</b>The silicotic alveolar macrophages were collected by bronchoalveolar lavage and incubated in vitro in the DMEM medium containing SiO₂ (50 µg/ml) and DMEM medium without SiO₂ for 18 h. Then the AM supernatant incubated for 18 h was collected. HELFs were isolated by organize paste block method, and incubated with AM supernatants. HELFs were divided into four groups: blank control groups, AM groups, SiO₂ + AM groups, SB203580 + SiO₂ + AM groups. The proliferation in the HELF was detected with MTT method and Flow cytometry.</p><p><b>RESULTS</b>The proliferation in the HELF acted with the conditioned AM supernatant fluid were more than blank control groups, AM groups and SB203580 + SiO₂ + AM groups [average optical density: (0.48 ± 0.03) vs (0.29 ± 0.01), (0.38 ± 0.02), (0.33 ± 0.03)], the values with MTT method were statistically different (P < 0.05); Proliferous index with flow cytometry in SiO₂ + AM groups (18.12 ± 0.82) was bigger than blank control groups (9.24 ± 0.48), AM groups (14.76 ± 0.43) and SB203580 + SiO₂ + AM groups (11.71 ± 0.70) and the values were statistically different(P < 0.05).</p><p><b>CONCLUSIONS</b>The AM supernatant stimulated by silicon dioxide can accelerate the proliferation in the HELF by activation of p38MAPK signal transduction pathway.</p>