Effect of p38MAPK on the proliferation in human embryonic lung fibroblasts in vitro

Objective 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. Methods 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. Results 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）. Conclusions The AM supernatant stimulated by silicon dioxide can accelerate the proliferation in the HELF by activation of p38MAPK signal transduction pathway. Key words: Silicosis;  Macrophages;  Mitogen-activated protein kinases;  Fibroblasts