Angiotensin II failitated angiogenesis mediated through macrophage migration inhibitory factor activation in hindlimb ischemic

巨噬细胞迁移抑制因子（macrophage migration inhibitory factor， MIF）是由氧化应激分泌的，在多种炎症条件下发挥重要作用，如调节巨噬细胞和T细胞的活化，它也作为刺激细胞生长和诱导其他细胞因子和酶如血管内皮生长因子（VEGF）和基质金属蛋白酶（matrix metalloproteinases, MMPs）的因子。VEGF和MMPs被认为影响许多细胞类型的新生血管。综上所述，我们评估了MIF可能是缺血反应中刺激血管生成的重要因素的假设。方法和结果：为了验证这一假设，我们检测了MIF过表达（TG）小鼠对组织缺血的血管生成反应。我们采用手术诱导的单侧后肢缺血模型建立MIF TG和野生型（WT）小鼠（C57BL/6）。采用激光多普勒灌注成像仪（缺血/正常灌注比）、血管造影（血管造影评分）和vWF抗体检测组织学毛细血管密度，分析缺血后肢血管新生和侧支血管形成情况。RT-PCR检测VEGF和MMPs（-2和-9）的信息表达和蛋白表达。与WT小鼠相比，MIF TG小鼠后肢缺血后血管生成和侧支血管形成明显增加。MIF TG小鼠与WT小鼠在非缺血区VEGF蛋白水平无显著差异。与WT小鼠相比，TG小鼠缺血区VEGF mRNA和蛋白表达水平升高。与WT小鼠相比，TG小鼠非缺血区MMP-9 mRNA表达增加。这种增加的表达在TG小鼠的缺血区域得到加强，尽管它们之间的MMP-2没有差异。抗MIF的中和抗体在缺血反应中显著抑制血管生成、VEGF表达和MMP-9表达

Background-Macrophage migration inhibitory factor (MIF), which we have reported to be secreted by oxidative stress, plays a crucial role in several inflammatory conditions such as regulating the activation of macrophages and T cells, and it also acts as a factor stimulating cell growth and inducing other cytokines and enzymes such as vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). VEGF and MMPs are thought to influence neovascularization in many cell type. Taken together, we assessed the hypothesis that MIF could be an important factor stimulating angiogenesis in response to ischemia. Methods and Results-To test the hypothesis, we examined angiogenesis in response to tissue ischemia in MIF overexpressed (TG) mice. We applied surgically-induced unilateral hindlimb ischemia model to MIF TG and wild type (WT) mice (C57BL/6). Angiogenesis and collateral vessel formation in the ischemic hindlimb were analyzed by using laser Doppler perfusion Imager (ischemic/normal perfusion ratio), angiography (angiogrphic score) and histological capillary density with vWF antibody. Message and protein expression of the VEGF and MMPs (-2 and -9) were determined with RT-PCR. Angiogenesis and collateral vessel formation in response to hindlimb ischemia were markedly increased in MIF TG mice compared with WT mice. VEGF protein levels were not different between the MIF TG mice and WT mice at non-ischemic area. In the ischemic area VEGF mRNA and protein expression levels were increased in the TG mice compared with the WT mice. MMP-9 mRNA expression was increased at non-ischemic region in the TG mice compared with the WT mice. This increased expression was reinforced in the ischmic region in the TG mice, although no difference in MMP-2 between them. A neutralizing antibody against MIF significantly suppressed angiogenesis, VEGF expression, and MMP-9 expression in response to ischemia