Naoum J J, Woodside K J, Zhang S, Rychahou P G, Hunter G C
Department of Surgery, Division of Vascular Surgery, University of Texas Medical Branch, Galveston, Texas 77555-0735, USA.
Transplant Proc. 2005 May;37(4):1880-4. doi: 10.1016/j.transproceed.2005.02.080.
Because of its antiproliferative properties and its known effects on plasma lipids, we evaluated the mechanisms underlying the effect of rapamycin (RPM) on endothelial nitric oxide synthase (eNOS) and matrix metalloproteinases in Apo-E knockout mice. Apo-E-/- mice fed a high-cholesterol diet were given RPM (3 mg/kg per day intraperitoneally) or no treatment for 10 weeks (n = 8 each). Blood was drawn for serum lipid analysis. Protein was extracted from the abdominal aortas for Western immunoblotting and zymography. Cellular localization was assessed by histology and immunohistochemistry. The data, expressed as mean +/- SEM, were compared by Student's t test or analysis of variance (ANOVA). Lipid levels at 10 weeks were similar in both groups except for higher triglyceride levels in RPM-treated animals. RPM-treated mice expressed greater amounts of eNOS and p-eNOS compared with controls (P < .05). Akt, p-Akt, Caveolin-1, and p-Caveolin-1 were not significantly affected by RPM treatment. RPM treatment was associated with increased activation of pro-MMP-9, a significant decrease in MMP-2 tissue levels, and corresponding increases in TIMP-2 and TIMP-3 expression. The increased expression and phosphorylation of eNOS with RPM appears to be regulated by mechanisms other than Akt or Caveolin-1. Alterations in eNOS expression, in addition to changes in MMP/TIMP ratios and MMP-2 and MMP-9 activation, may partially explain the changes observed in the aorta of treated Apo-E-/- mice induced by RPM.
鉴于雷帕霉素（RPM）具有抗增殖特性及其对血浆脂质的已知作用，我们评估了RPM对载脂蛋白E基因敲除小鼠内皮型一氧化氮合酶（eNOS）和基质金属蛋白酶作用的潜在机制。给喂食高胆固醇饮食的载脂蛋白E基因敲除小鼠腹腔注射RPM（每天3 mg/kg）或不进行处理，持续10周（每组n = 8）。采集血液进行血清脂质分析。从腹主动脉提取蛋白质用于蛋白质免疫印迹和酶谱分析。通过组织学和免疫组织化学评估细胞定位。数据以平均值±标准误表示，采用Student's t检验或方差分析（ANOVA）进行比较。除了RPM处理组动物的甘油三酯水平较高外，两组在10周时的脂质水平相似。与对照组相比，RPM处理的小鼠表达更多的eNOS和磷酸化eNOS（P < 0.05）。Akt、磷酸化Akt、小窝蛋白-1和磷酸化小窝蛋白-1不受RPM处理的显著影响。RPM处理与前基质金属蛋白酶-9的激活增加、MMP-2组织水平的显著降低以及组织金属蛋白酶抑制剂-2（TIMP-2）和组织金属蛋白酶抑制剂-3（TIMP-3）表达的相应增加有关。RPM使eNOS表达和磷酸化增加似乎是由Akt或小窝蛋白-1以外的机制调节的。除了MMP/TIMP比值以及MMP-2和MMP-9激活的变化外，eNOS表达的改变可能部分解释了RPM处理的载脂蛋白E基因敲除小鼠主动脉中观察到的变化。
