Supplementary Material for: Resveratrol Inhibits Neointimal Growth after Arterial Injury in High-Fat-Fed Rodents: The Roles of SIRT1 and AMPK

We have shown that both insulin and resveratrol (RSV) decrease neointimal hyperplasia in chow-fed rodents via mechanisms that are in part overlapping and involve the activation of endothelial nitric oxide synthase (eNOS). However, this vasculoprotective effect of insulin is abolished in high-fat-fed insulin-resistant rats. Since RSV, in addition to increasing insulin sensitivity, can activate eNOS via pathways that are independent of insulin signaling, such as the activation of sirtuin 1 (SIRT1) and AMP-activated kinase (AMPK), we speculated that unlike insulin, the vasculoprotective effect of RSV would be retained in high-fat-fed rats. We found that high-fat feeding decreased insulin sensitivity and increased neointimal area and that RSV improved insulin sensitivity (<i>p &lt;</i> 0.05) and decreased neointimal area in high-fat-fed rats (<i>p &lt;</i> 0.05). We investigated the role of SIRT1 in the effect of RSV using two genetic mouse models. We found that RSV decreased neointimal area in high-fat-fed wild-type mice (<i>p &lt;</i> 0.05), an effect that was retained in mice with catalytically inactive SIRT1 (<i>p &lt;</i> 0.05) and in heterozygous SIRT1-null mice. In contrast, the effect of RSV was abolished in AMKPα2-null mice. Thus, RSV decreased neointimal hyperplasia after arterial injury in both high-fat-fed rats and mice, an effect likely not mediated by SIRT1 but by AMPKα2.

本研究证实，胰岛素与白藜芦醇（resveratrol, RSV）均可通过部分重叠的机制抑制普通饲料喂养啮齿类动物的内膜增生，此类机制涉及内皮型一氧化氮合酶（endothelial nitric oxide synthase, eNOS）的激活。然而，在高脂喂养的胰岛素抵抗大鼠中，胰岛素的这种血管保护作用会被消除。鉴于白藜芦醇除可提升胰岛素敏感性外，还可通过不依赖胰岛素信号通路的途径激活eNOS，例如沉默信息调节因子1（sirtuin 1, SIRT1）与腺苷酸活化蛋白激酶（AMP-activated kinase, AMPK）的激活，因此本研究推测：与胰岛素不同，白藜芦醇的血管保护作用在高脂喂养大鼠中仍可保留。本研究发现，高脂喂养会降低胰岛素敏感性并增大内膜面积；而白藜芦醇可提升高脂喂养大鼠的胰岛素敏感性（P<0.05），同时减小其内膜面积（P<0.05）。本研究通过两种基因工程小鼠模型，探究了SIRT1在白藜芦醇发挥作用过程中的角色。本研究观察到，白藜芦醇可减小高脂喂养野生型小鼠的内膜面积（P<0.05）；该效应在催化失活型SIRT1小鼠（P<0.05）与杂合子SIRT1敲除小鼠中均得以保留。与之相反，白藜芦醇的该效应在AMPKα2敲除小鼠中被完全消除。综上，在高脂喂养的大鼠与小鼠中，白藜芦醇均可抑制动脉损伤后的内膜增生，该效应大概率并非由SIRT1介导，而是通过AMPKα2实现的。