| Objective:To observe changes of calcium signal in bronchial epithelial cells and pulmonary macrophages treated with hydrogen peroxide and X-ray, and to investigate the mechanism of radiation-induced pulmonary fibrosis.Methods:Human bronchial epithelial cells (HBE) and rat pulmonary macrophages (NR8383) were cultured, and then treated them with different concentrations of hydrogen peroxide. Calcium signal in the cells was detected by microscopic fluorescence imaging system. Treated HBE and NR8383 with X-ray, then calcium signal in the cells was also detected by microscopic fluorescence imaging system.Treated HBE and NR8383 with hydrogen peroxide after exposure to X-ray, calcium signal was recorded by the same method which was previously introduced. Results:1 There was no auto-calcium oscillation found in human bronchial epithelial cells, but auto-calcium oscillation existed in pulmonary macrophages.2 Hydrogen peroxide (50-500μmol/l) induced calcium oscillation in HBE. The concentration of hydrogen peroxide which induced the highest frequency of calcium oscillation was 150μmol/l. Hydrogen peroxide inhibited auto-calcium oscillation found in pulmonary macrophages.3 X-ray decreased the frequency of calcium oscillation induced by hydrogen peroxide in HBE, but X-ray did not change the amplitude of calcium oscillation. Moreover, auto-calcium oscillation in pulmonary macrophages disappeared after exposure to X-ray.ConclusionHydrogen peroxide and X-ray can induce the changes of calcium signal and frequency of oscillation in human bronchial epithelial cells and pulmonary macrophages. These may be involved in the mechanism of radiation-induced pulmonary fibrosis. |
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