The Effects Of Simvastatin On Production Of NO,NOS,ET-1 In Endothelial Cells And Its Mechanism

Objctives: To observe the influence of simvastatin on TNF- α induced production of nitric oxide, nitric oxide synthase and endothelin-1 in human endothelial cells and to investigate the non-lipid mechanisms of simvastatin on anti-atherosclerosis.Methods: 1. ECV304 cells were cultured in vitro.2. ECV304 cells were stimulated with TNF-α(0, 10, 50, 100ng/ml) for 24 hour.3. simvastatin (0.1, 1.0, 10.0 μ mmol/L) was used to incubate ECV304 cells for 24 hour while stimulation with TNF- α (50ng/ml).4.ECV304 cells were also co-incubated with TNF- α (50ng/ml) + simvastatin (10.0 μ mmol/L) + mevalonate(0.2mmol/L) for 24 hour.5.NO in the supematants were measured by nitrate reductase assay, the activity of NOS were measured by chemical colorimetry assay and ET-1 were measured by radioimmunoassay.Results: 1.After stimulation of ECV304 cells with TNF- α , the concentration of NO and the activity of cNOS in the supematants were significantly lower than that of the controlgroup, while the concentration of ET-1 and the activity of iNOS were significantly higher than that of the control group. 2. The addition of simvastatin of different concentrations to ECV304 cells in presence of TNF- a (50ng/ml) significantly increased the production of NO and the activity of cNOS compared with control group, significantly decreased the production of ET-1 and the activity of iNOS. Mevalonate could reverse these effects of simvastatin. Conclusions: 1. TNF- a could inhibit the production of NO and the activity ofcNOS but induce the production of ET-1 and increase theactivity of iNOS.2. By inhibiting the production of ET-l, increasing the production of NO and the activity of cNOS, simvastatin plays an essential role in keeping the endothelial function and anti-atherosclerosis independent of cholesterol-lowing effects.3. These pleiotropic effects of simvastatin might be partly mediated by its inhibition on the mevalonate pathway.