Atorvastatin attenuates homocysteine-induced apoptosis in human umbilical vein endothelial cells via inhibiting NADPH oxidase-related oxidative stress-triggered p38MAPK signaling

Aim: To examine the effect of atorvastatin on homocysteine (Hcy)-induced reactive oxygen species (ROS) production and apoptosis in human umbilical vein endothelial cells (HUVECs). Methods: HUVECs were cultured with Hcy (0.1-5 mmol/L) in the presence or absence of atorvastatin (1-100 mu mol//L) or various stress signaling inhibitors, including the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor diphenylene iodonium (DPI, 10 mu mol/L), the p38 mitogen-activated protein kinase (p38 MAPK) inhibitor SB203580 (10 mu mol/L) and antioxidants N-acetyl cysteine (NAC, 1 mmol/L). Cell apoptosis was evaluated by Annexin V/propidium iodide staining and flow cytometry. ROS were detected by 2',7'-dichlorodihydrofluorescein diacetate (H2DCFH-DA). NADPH oxidases were evaluated with lucigenin-enhanced chemiluminescence. Hcy-induced expression of p38MAPK protein was measured by Western blotting analysis. Results: Atorvastatin inhibited endothelial cell apoptosis induced by 1 mmol/L Hcy in a dose-dependent manner and the maximal inhibitory effect was reached at 100 mu mol/L. Atorvastatin (10 mu mol/L) significantly suppressed Hcy (1 mmol/L for 30 min) induced ROS accumulation (3.17 +/- 0.33 vs 4.34 +/- 0.31, P<0.05). Atorvastatin (10 mu mol/L) also antagonized Hcy (1 mmol/L for 30 min) induced activation of NADPH oxidase (2.57 +/- 0.49 vs 3.33 +/- 0.6, P<0.05). Furthermore, atorvastatin inhibited Hcy-induced phosphorylation of p38 MAPK (1.7 +/- 0.1 vs 2.22 +/- 0.25, P<0.05), similar effects occurred with DPI, NAC and SB203580. Conclusion: Atorvastatin may inhibit Hcy-induced ROS accumulation and endothelium cell apoptosis through an NADPH oxidase and/or p38MAPK-dependent mechanisms, all of which may contribute to atorvastatin-induced beneficial effect on endothelial function.