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

To study the inhibitory effect of oxymatrine (OM) on quartz-induced secretion of TNF-alpha 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-alpha in the media was measured by double-antibody sandwich ELISA. The TNF-alpha (10 ng/mL) and OM of different concentrations were added into the media containing the fibroblasts of the 4th generations from neonate rats. The gamma 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 microg/ mL-1600 microg/mL, OM inhibited the secretion of TNF-alpha 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 microg/mL-1600 microg/mL and the concentration of 10 ng/mL TNF-alpha. When compared with 10 ng/mL TNF-alpha, 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 microg/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-alpha promoting the proliferation of fibroblasts. It achieves its inhibitory effect on the promoting effect of TNF-alpha on fibroblast proliferation by elevating the cAMP level and decreasing the release of Ca2+.