Expression and significance of death receptors in alveolar macrophages from silicosis patients

Objective To explore the expression of death receptors(DR) in alveolar macrophages of silicosis patients and the relationship between DR levels and lung fibrosis.Methods Forty-eight male silicosis patients and thirteen male observation objects treated by whole lung lavage were chosen as subjects.Thirteen male health people with normal lung X-ray photograph were selected as the control group.The alveolar macrophags(AM) were collected,purified and incubated at 37 ℃ for 24 hours.After 3 kinds of soluble DR(sDR) were determined by ELISA,membrane-bound DR(mDR) were detected by Western blot.The relationships between DR and silica exposure related factors were analyzed.Results The grayscales of mDR in those of the subjects were thicker than those of the controls,and increased with the lung fibrosis progression.The membrane-bound apoptosis related factor 1(mFas) and membrane-bound tumor necrosis factor reeptor 1(mTNFR1) levels in silicosis patients were higher than those of the control group and observation objects(P 0.05),and increased with the progression of silicosis.The levels of soluble apoptosis related factor 1(sFas) and soluble tumor necrosis factor receptor 1 in those of silicosis patients were lower than those of observation objects(P 0.05),and sFas decreased with the progression of silicosis.Conclusion The upregulation of mFas and mTNFR1,downregulation of sFas induced by silicon may play an important role in silicosis onset and development.Death receptor signal activation maybe one of the pathophysiological mechanisms of silicosis.