Inhibitory Effect of Oxymatrine on Quartz-induced Secretion of TNF-α by the Pulmonary Alveolar Macrophages in the Fibroblast Proliferation

The massive proliferation of pulmonary fibroblasts is the common consequence shared by lung diseases. The over-expression of TNF-α plays an important role in the proliferation of pulmonary fibroblasts[1, 2]. Under patho-logical conditions, TNF-α is predominantly secreted by activated alveolar macrophages of lung. The high level of TNF-α acts on the receptors on the cell membrane of fibroblasts, mediates the conduction of intracellular sig-nals and eventually activates the nuclear factor…

Inhibitory effect of oxymatrine on quartz-induced secretion of TNF-α by the pulmonary alveolar macrophages in the fibroblast proliferation

Summary To study the inhibitory effect of oxymatrine (OM) on quartz-induced secretion of TNF-α in the fibroblast proliferation, a given amount of quartz powder and OM of different concentrations were put into the media of pure culture containing macrophages. After 24 h of the culture, the TNF-α in the media was measured by double-antibody sandwich ELISA. The TNF-α (10 ng/mL) and OM of different concentrations were added into the media containing the fibroblasts of the 4th generations from neonate rats. The γ values of cAMP and cGMP in fibroblasts were determined by the radioimmunoassay and the concentrations of cAMP and cGMP were calculated according to standard curve. The intracellular Ca²⁺ was determined by flow cytometry and cell proliferation was detected by MTT. Our results showed that at the concentrations between 200 μg/ mL-1600 μg/mL, OM inhibited the secretion of TNF-α by alveolar macrophages (AM) in a dose-dependent manner. Especially, there were significant differences, to various degrees, in the inhibitory effect of OM between the concentration range of 800 μg/mL-1600 μg/mL and the concentration of 10 ng/mL TNF-α. When compared with 10 ng/mL TNF-α, OM of different concentrations could dose-independently increased the level of intracellular cAMP and decreased the level of cGMP, thereby raising the ratio of cAMP/cGMP and lowering the concentrations of intracellular Ca²⁺. Moreover, OM of 800 μg/mL had the strongest inhibitory effect on cell proliferation and at this concentration, the cAMP/cGMP was highest and Ca²⁺ was at the lowest level. We are led to conclude that OM can antagonize the damaging effect of quartz on the membrane of AM and the effect of TNF-α promoting the proliferation of fibroblasts. It achieves its inhibitory effect on the promoting effect of TNF-α on fibroblast proliferation by elevating the cAMP level and decreasing the release of Ca²⁺. This project was supported by a grant from the Foundation of Natural Science of Shanxi Province (No. 20021077) and the Innovation Fund for College Students of Shanxi Medical University (2004-46).