Endocrine Abstracts

Many evidences have shown that the beneficial effect of statins on the cardiovascular disease may be not only due to their cholesterol-lowering, but also may result from their non-lipid related effects, such as the improvement of endothelial function, the inhibition of smooth muscle proliferation, etc\. Here we investigated the effect of fluvastatin on H₂O₂-induced oxidative cell damage and the underlying mechanism in human umbilical vein endothelial cells (HUVECs).

Methods: Primary cultured HUVECs were maintained in a CO₂ incubator at 37  °C. Bcl-2 siRNA and anti-Bcl2 antibody were purchased from Strategene Co. The cells were transfected with siRNA using Lipofectamine 2000. The cell proliferation, apoptosis and necrotic death were assayed with WST-1, cell death ELISA and cytotocity kits respectively, which were purchased from Roche Co. The apoptosis was also observed with trypan blue and Hoechst 33342 nuclei staining.

Results: H₂O₂ at 100 μM significantly induced apoptotic cell death after 24 h cell culture. Fluvastatin at low concentration (10–100 nM) prevented H₂O₂-induced apoptosis, as determined by the DNA fragmentation assay and cell counting with trypan blue and Hoechst 33342 staining. This protective effect was mediated by the upregulation of Bcl-2 expression probed by real-time PCR and western blotting. Using siRNA to knock down the expression of Bcl-2, the protective effect of fluvastatin was abolished. Fluvastatin had no direct effect on the H₂O₂-senstive TRPM2 cationic channel. On the other hand, fluvastatin at moderate or high concentration (250–1000 nM) inhibited cell proliferation and induced apoptosis, but had no effect on cell necrosis.

Conclusions: Fluvastatin has a potent protective effect against H₂O₂-induced apoptosis. This effect is mediated by the upregulation of Bcl-2 expression. The finding provides the first evidence that Bcl-2 plays an essential role in the protective effect of fluvastatin under oxidative stress.