OBJECTIVETo observe the changes in activities of superoxide dismutase (SOD) and glutathione peroxide (GSH-Px) in the induced sputum of silicosis patients, and to investigate the roles of SOD and GSH-Px in the development and progression of silicosis and the significance of measuring activities of SOD and GSH-Px in induced sputum among silicosis patients.

METHODSFifty hotel attendants were chosen as control group, 50 workers with more than one year of silica dust exposure as dust exposure group, 32 silica dust-exposed workers as observation subject group, and 52 silicosis patients as silicosis group. The activities of SOD and GSH-Px in their induced sputum were measured by enzyme-linked immunosorbent assay.

RESULTSCompared with the control group, the observation subject group and silicosis group had significantly decreased SOD activity (68.16 ± 30.17 and 66.38 ± 47.32 U/ml vs 75.81 ± 11.92 U/ml, P < 0.05); compared with the dust exposure group, the silicosis group had significantly decreased SOD activity (66.38 ± 47.32 U/ml vs 70.12 ± 14.31 U/ml, P < 0.05). Compared with the control group and dust exposure group, the observation subject group and silicosis group had significantly increased GSH-Px activity (268.21 ± 15.45 and 279.34 ± 29.26 U/ml vs 224.22 ± 12.64 and 236.41 ± 14.54 U/ml, P < 0.05 or P < 0.01).

CONCLUSIONThe SOD activity in dust exposure group and silicosis group decreased, but there were no significant differences between patients with different stages of silicosis. The GSH-Px activity in dust exposure group and silicosis group was significantly higher than that in control group, and there were significant differences between patients with different stages of silicosis. These suggest that the imbalance of oxidative/antioxidant systems is associated with the development and progression of silicosis.