Effects of Cytokines Induced by Mineral Dust on Lung Fibroblasts In Vitro

Effects of cytokines induced by asbestos on lung fibroblasts in vitro: Li Ren ZHOU, et al. Department of Occupational Health, Suzhou Medical College, Suzhou China—Rabbit's alveolar macrophages (AM) obtained by lavage were cultured with three mineral dusts (quartz, asbestos fibre and uranium dust) in vitro. The activity of tumor necrosis factor (TNF) and lung fibroblast (LF) proliferation were measured by 3H-thymidine (3H-TdR) incorporation, the collagen synthesis in LF by 14C-proline (14C-Pro), interleukin-6 (IL-6) activity in the supernatant of AM by 3-(4, 5-dimethyiazo-2-yl)-2, 5-diphenyltetrazolium bromide; thiazoylblue (MTT) colorimetry, and the total hydroxy-proline (HOP) in LF by the chloromine-T method. The assay of the inhibiting effect of anti-TNF antibody and IFNγon LF proliferation and collagen synthesis were carried out. The results show that the three mineral dusts can induce AM to release TNF and IL-6. When the three mineral dusts were added at a dose of 200 μg/ml, the levels of TNF were 1369 U/ml, 1198 U/ml and 852 U/ml, and the levels of IL-6 were 1336U/ml, 1511U/ml and 1335 U/ml, which were significantly higher than those in the TiO2 control. The LF proliferation and collagen synthesis can be increased by the supernatant of the AM treated with the three minerl dusts. 3H-TdR incorporations were 22320 dpm, 12547 dpm and 15048 dpm (at a 1:2 dilution of AM supernatant), which was significantly higher than in the TiO2 and Hank's control (P<0.01). 14C-Pro incorporations were 34001 dpm, 16319 dpm and 22550 dpm (at a dust concentration of 200 μg/ml), which were much higher than in the TiO2 and Hank's control (P<0.01). Total amounts of HOP in WI-38 cell activated by supernatants of AM induced by the three mineral dusts were 22.41 μg/ml, 24.00 μg/ml and 21.29 μg/ml (at a dust concentration of 200 μg/ml), which were significantly higher than in the TiO2 and Hank's control (P<0.01). Both anti-tumor necrosis antiboby and interferon-gamma can inhibit the proliferation of the LF and decrease collagen synthesis.