Vinpocetine attenuates lipid accumulation and atherosclerosis formation

Abstract

Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

Figure 1

Effects of vinpocetine on atherosclerotic lesion formation. (A) Representative En face images of Oil-red O stained aorta from ApoE knockout mice fed with normal chow (NC) or a high-fat diet (HF) for 16 weeks with i.p injection of 5mg/kg/day vinpocetine (Vinp) or vehicle saline (Veh). (B) Quantitative data showing the percentage of atherosclerotic lesion in entire aorta. (C) Representative images of the aortic sinus stained with H&E from mice fed with high-fat diet and injected with vinpocetine or vehicle. (D) Quantitative data of showing intimal lesion areas in the aortic root. Values are means ± SEM (n=7 for both vinpocetine and vehicle groups). *P<0.05 compared with vehicle group.

Figure 2

Effects of vinpocetine on ox-LDL uptake and accumulation in macrophages (A–B). Representative images (A) and quantitative data (B) show that vinpocetine inhibits Dil-ox-LDL uptake and accumulation in RAW264.7 cells. RAW264.7 cells were treated with different doses of vinpocetine for 24 h in DMEM containing 0.1% FBS, then loaded with 10 μg/ml Dil-ox-LDL for an additional 4 h. After nuclear staining with DAPI, cellular Dil-ox-LDL was monitored with a fluorescent microscope. Red: Dil-ox-LDL. Blue: DAPI. (C–D) Representative images (C) and quantitative data (D) show that vinpocetine inhibits regular ox-LDL uptake and accumulation as assessed by Oil-red O staining. Cells were observed with bright-field microscopy. Values are means ± SD from at least three independent experiments. *P<0.05 vs. control with vehicle (zero vinpocetine).

Figure 3

Effects of vinpocetine on LOX-1 expression in vitro and in vivo. (A) Vinpocetine inhibits ox-LDL-induced LOX-1 expression in macrophages. RAW264.7 cells were starved in 0.1% FBS-starved for 24 h, pretreated with indicated doses of vinpocetine for 1 h, followed by treatment with 50 μg/ml ox-LDL for 24 h, the mRNA levels were measured by real time RT-PCR. Values are means ± SD from at least three independent experiments. *P<0.05 vs. ox-LDL with zero vinpocetine. (B–E) Vinpocetine inhibits LOX-1 expression in vivo. Representative images (B) stained with Oil-red O (left panels), LOX-1 antibody (middle panels), or macrophage marker Mac-2 (right panels), in aortic sinus of ApoE knockout mice fed with a high-fat diet (HF) for 16 weeks with i.p injection of 5 mg/kg/day vinpocetine (Vinp) or vehicle (Veh). (C–E) Quantitative data of Oil-red O, LOX-1 and MAC-2 positive areas. Values are means ± SEM from at least five animals. *P<0.05 compared with saline i.p injection. Magnification: ×100.