Abstract

To explore the effect and molecular mechanism of total flavonoids of Astragalus on the apoptosis and inflammation of alveolar epithelial cells induced by tumor necrosis factor alpha. Human alveolar epithelial cells were divided into control group, tumor necrosis factor alpha group, tumor necrosis factor alpha+trifluoroacetic acid-low, tumor necrosis factor alpha+trifluoroacetic acid-medium, tumor necrosis factor alpha+trifluoroacetic acid-high group, tumor necrosis factor alpha+anti-microRNA-NC group, tumor necrosis factor alpha+microRNA-221 inhibitor group, tumor necrosis factor alpha+trifluoroacetic acid-high+microRNA-NC group, tumor necrosis factor alpha+trifluoroacetic acid-H+microRNA-221 mimic group. Real-time fluorescence quantitative polymerase chain reaction was used to detect the expression of microRNa-221; (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to detect the cell proliferation inhibition rate; flow cytometry to detect the apoptosis of alveolar epithelial cells; enzyme-linked immunosorbent assay to detect the levels of interleukin-1 beta, I interleukin-6 and interleukin-10. In tumor necrosis factor alpha-induced alveolar epithelial cells, the expression of microRNA-221 was increased, the cell proliferation inhibition rate and apoptosis rate were increased, the levels of interleukin-1 beta, interleukin-6 were increased and the level of interleukin-10 was decreased (p<0.05). After treatment with medium and high concentrations of total flavones of Astragalus, the expression of microRNA-221 in alveolar epithelial cells induced by tumor necrosis factor alpha was decreased, cell proliferation inhibition rate and apoptosis rate were decreased, interleukin-1 beta and interleukin-6 levels were decreased and interleukin-10 was increased (p<0.05). Inhibition of microRNA-221 expression can inhibit tumor necrosis factor alpha induced apoptosis and inflammation of alveolar epithelial cells. Overexpression of microRNA-221 can reverse the effect of total flavonoids of Astragalus on apoptosis and inflammation of alveolar epithelial cells induced by tumor necrosis factor alpha. Total flavones of Astragalus inhibited tumor necrosis factor alpha induced apoptosis and inflammation of alveolar epithelial cells by down-regulating microRNA-221.