Li Ka Shing Institute of Health Sciences, Institute of Vascular Medicine, and School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Cardiovasc Res. 2011 Nov 1;92(2):267-75. doi: 10.1093/cvr/cvr233. Epub 2011 Aug 29.
Endothelial dysfunction is caused by reduced nitric oxide (NO) bioavailability and/or over-produced reactive oxygen species (ROS). The present study investigated a vascular benefit of AVE3085, an endothelial nitric oxide synthase (eNOS) enhancer, in preserving endothelial function in diabetic mice and the mechanisms involved.
Male db/db and db/m(+) mice were orally administered AVE3085 for 7 days (10 mg kg(-1) day(-1)). Vascular reactivity of arteries was studied via myography under both isometric and isobaric conditions. ROS levels in aortas were determined using dihydroethidium fluorescence dye and electron paramagnetic resonance spin trapping. Chronic treatment with AVE3085 reduced blood pressure, enhanced endothelium-dependent relaxations (EDR) to acetylcholine in aortas, mesenteric, and renal arteries, lowered oxidative stress, and augmented the attenuated flow-dependent dilatation in mesenteric resistance arteries from db/db mice. Incubation of aortas from C57BL/6J mice in high glucose (30 mmol L(-1)) culture medium for 48 h impaired EDR and elevated ROS generation, and these effects were reversed by co-treatment with AVE3085 (1 µmol L(-1)). Benefits of AVE3085 were abolished by the transcription inhibitor actinomycin D, the NOS inhibitor N(G)-nitro-L-arginine methyl ester, and in eNOS(-/-) mice. NO production in primary endothelial cells from mouse aortas was detected with a NO-sensitive fluorescence dye. Protein expression was assayed by western blotting. Treatment with AVE3085 enhanced NO production in endothelial cells and eNOS expression in aortas.
AVE3085 ameliorates endothelial dysfunction in db/db mice through increased NO bioavailability, which reduces oxidative stress in the vascular wall. Targeting eNOS and NO production may be a promising approach to combat diabetic vasculopathy.
内皮功能障碍是由一氧化氮（NO）生物利用度降低和/或活性氧（ROS）产生过多引起的。本研究探讨了内皮型一氧化氮合酶（eNOS）增强剂 AVE3085 在保护糖尿病小鼠内皮功能方面的血管益处及其相关机制。
雄性 db/db 和 db/m(+) 小鼠连续 7 天口服 AVE3085（10mg/kg/天）。通过等长和等压条件下的肌动描记术研究动脉血管反应性。使用二氢乙啶荧光染料和电子顺磁共振自旋捕获法测定主动脉中的 ROS 水平。慢性 AVE3085 处理降低了血压，增强了主动脉、肠系膜和肾动脉对乙酰胆碱的内皮依赖性舒张作用，降低了氧化应激，并增强了 db/db 小鼠肠系膜阻力动脉中减弱的血流依赖性扩张。将 C57BL/6J 小鼠的主动脉在 30mmol/L 高葡萄糖培养基中孵育 48 小时，损害了 EDR 并增加了 ROS 的产生，而 AVE3085（1µmol/L）的共同处理则逆转了这些作用。转录抑制剂放线菌素 D、NOS 抑制剂 N(G)-硝基-L-精氨酸甲酯和 eNOS(-/-) 小鼠消除了 AVE3085 的作用。使用 NO 敏感荧光染料检测来自小鼠主动脉的原代内皮细胞中的 NO 产生。通过 Western 印迹法测定蛋白表达。AVE3085 处理增强了内皮细胞中的 NO 产生和主动脉中的 eNOS 表达。
AVE3085 通过增加 NO 生物利用度改善 db/db 小鼠的内皮功能障碍，从而减少血管壁中的氧化应激。靶向 eNOS 和 NO 产生可能是对抗糖尿病血管病变的一种有前途的方法。
