Berberine combined with atorvastatin downregulates LOX-1 expression through the ET-1 receptor in monocyte/macrophages

Studies have shown that the oxidative modification of low-density lipoprotein (oxLDL) plays a major role in atherogenesis. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) mediated the transport of oxLDL into macrophages, which promoted foam cell formation. Targeting LOX-1 may therefore be a promising approach to inhibit atherosclerosis. In the present study, we aimed to investigate the effect of berberine combined with atorvastatin on LOX-1 and explore the underlying molecular mechanism involved. Expression of LOX-1 in monocyte-derived macrophages (MDMs) exposed to berberine (0, 0.1, 1, 10 and 100 nM) and atorvastatin (100 nM) were analyzed by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot analysis. Results showed that the expression of LOX-1 was decreased in a dose-dependent manner. Additionally, knockdown of the endothelin-1 (ET-1) receptor significantly blocked the inhibitory effect of berberine on LOX-1 expression. Body weight (BW), liver weight (LW) and kidney weight (KW) in the model rats were markedly increased at concentrations of berberine >= 1 mu mol/kg, while heart weight (HW) and spleen weight (SW) remained constant among all groups. Berberine combined with atorvastatin also decreased serum total cholesterol (TC), triglyceride (TG) and low-density lipoprotein-cholesterol (LDL-C) levels in the rat model as well as inflammation and oxidative stress. Furthermore, plasma ET-1 levels and LOX-1 expression were decreased by berberine combined with atorvastatin treatment, and the inhibitory effect on LOX-1 was impeded by an ET-1 receptor antagonist. The results demonstrated that berberine combined with atorvastatin downregulates LOX-1 expression through ET-1 receptors in monocyte/macrophages in vitro and in vivo.