Exposure to diesel exhaust upregulates COX-2 expression in ApoE knockout mice.
Exposure to diesel exhaust upregulates COX-2 expression in ApoE knockout mice.
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DOI：
10.3109/08958378.2012.696221
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发表时间：
2012-07
影响因子：
2.1
通讯作者：
van Eeden SF
中科院分区：
文献类型：
--
作者：
Bai N;Tranfield EM;Kavanagh TJ;Kaufman JD;Rosenfeld ME;van Eeden SF
我们已经证明，吸入柴油废气(DE)会导致动脉粥样硬化的进展，然而，其机制尚不完全清楚。我们假设暴露于DE上调了环氧合酶(COX)的表达和活性，这可能在DE诱导的动脉粥样硬化中起作用。以普通饲料喂养的APOE基因敲除小鼠(30周龄)暴露于DE(颗粒物浓度为200μg/m~3)或过滤空气(对照组)中7周(6h/d，5天/周)。免疫组织化学方法检测COX-1和COX-2的蛋白表达，实时定量聚合酶链式反应检测COX-2的表达。为了检测环氧合酶活性，将胸主动脉安装在线状肌图仪上，并在有和没有环氧合酶拮抗剂(消炎痛)存在的情况下测量苯肾上腺素(PE)刺激的血管收缩。通过尿中前列环素I2的主要代谢产物2，3-二氢-6-酮-前列腺素F1α水平进一步检测COX-2活性。免疫组织化学分析显示，DE暴露增加了COX-2在胸主动脉(P<；0.01)和主动脉根部(P<；0.03)的表达，但不影响COX-1的表达。主动脉病变组织中COX-2的表达与血管内皮细胞含量呈正相关(R2=0.4081，p<；0.008)。在DE暴露后，在消炎痛存在的情况下，最大血管收缩的分数变化减弱了3倍(p<；0.02)。DE组尿2，3-二-6-酮-前列腺素F1α水平是对照组的15倍(p<；0.007)。DE暴露后，COX-2(p<；0.006)和PGI合成酶(p<；0.02)的基因表达显著增加，而COX-1的表达无明显变化。我们发现DE吸入增强了COX-2的表达，这也与主动脉病变的表型变化有关。
We have shown that diesel exhaust (DE) inhalation caused progression of atherosclerosis; however, the mechanisms are not fully understood. We hypothesize that exposure to DE upregulates cyclooxygenase (COX) expression and activity, which could play a role in DE-induced atherosclerosis. ApoE knockout mice (30-week old) fed with regular chow were exposed to DE (at 200 μg/m3 of particulate matter) or filtered air (control) for 7 weeks (6 h/day, 5 days/week). The protein and mRNA expression of COX-1 and COX-2 were evaluated by immunohistochemistry analysis and quantitative real-time PCR, respectively. To examine COX activity, thoracic aortae were mounted in a wire myograph, and phenylephrine (PE)-stimulated vasoconstriction was measured with and without the presence of COX antagonists (indomethacin). COX-2 activity was further assessed by urine 2,3-dinor-6-keto PGF1α level, a major metabolite of prostacyclin I2 (PGI2). Immunohistochemistry analysis demonstrates that DE exposure enhanced COX-2 expression in both thoracic aorta (p < 0.01) and aortic root (p < 0.03), with no modification of COX-1 expression. The increased COX-2 expression was positively correlated with smooth muscle cell content in aortic lesions (R2 = 0.4081, p < 0.008). The fractional changes of maximal vasoconstriction in the presence of indomethacin was attenuated by 3-fold after DE exposure (p < 0.02). Urine 2,3-dinor-6-keto PGF1α level was 15-fold higher in DE group than the control (p < 0.007). The mRNA expression of COX-2 (p < 0.006) and PGI synthase (p < 0.02), but not COX-1, was significantly augmented after DE exposure. We show that DE inhalation enhanced COX-2 expression, which is also associated with phenotypic changes of aortic lesion.