Nitric oxide synthase activity in the abdominal aorta of rats is decreased after 4 weeks of simulated microgravity
Nitric oxide synthase activity in the abdominal aorta of rats is decreased after 4 weeks of simulated microgravity
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DOI：
10.1111/j.1440-1681.2011.05565.x
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发表时间：
2011-10-01
影响因子：
2.9
通讯作者：
Ma, Jin
中科院分区：
文献类型：
--
作者：
Ren, Xin-Ling;Zhang, Ran;Ma, Jin
1.本研究旨在探讨模拟微重力对大鼠腹主动脉舒张反应性及L-精氨酸（L-Arg）-一氧化氮（NO）-环鸟苷酸（cGMP）通路的影响.将20只健康雄性SD大鼠随机分为对照组和模拟微重力组。模拟微重力组大鼠进行后肢减重。4周后，在离体腹主动脉环中检测动脉舒张反应性。Western印迹法测定内皮型和诱导型NO合酶（NOS）蛋白含量。用化学发光法测定NO的稳定代谢产物硝酸盐和亚硝酸盐（NO（x））的总浓度。通过[（3）H]-L-精氨酸转化为[（3）H]-L-瓜氨酸，测定腹主动脉一氧化氮合酶活性。结果表明，模拟失重大鼠动脉环对L-精氨酸和乙酰胆碱的舒张反应减弱，而对硝普钠和8-溴-cGMP的舒张反应与对照组相似。eNOS和iNOS的表达在两组间无显著性差异。HU大鼠腹主动脉中的NOx浓度明显低于对照组大鼠。主动脉一氧化氮合酶活性在HU 4周后下降。数据表明，内皮依赖性血管舒张在腹主动脉减少，由于4周的模拟微重力大鼠，这种受损的扩张反应可能是由于NOS活性降低。
1. The aim of the present study was to investigate the effects of simulated microgravity on the arterial dilatory responsiveness and L-arginine (L-Arg)-nitric oxide (NO)-cGMP pathway in the abdominal aorta of rats.2. Twenty healthy male Sprague-Dawley were randomly divided into control and simulated microgravity groups. Rats in the simulated microgravity group were subjected to hindlimb unweighting (HU). After 4 weeks, arterial dilatory responsiveness was examined in vitro in isolated abdominal aortic rings. Western blotting was used to measure endothelial (e) and inducible (i) NO synthase (NOS) protein content. Total concentrations of nitrate and nitrite (NO(x)), the stable metabolites of NO, were determined by the chemiluminescence method. Nitric oxide synthase activity in the abdominal aorta was determined through the conversion of [(3)H]-L-Arg to [(3)H]-L-citrulline.3. The data showed that the dilatory responses of the arterial rings to L-Arg and acetylcholine decreased in rats exposed to simulated microgravity, but the dilatory responses to sodium nitroprusside and 8-bromo-cGMP were similar in both simulated microgravity and control rats. The expression of eNOS and iNOS did not differ significantly between the two groups. The NOx concentration in the abdominal aorta of HU rats was significantly less than that in control rats. Nitric oxide synthase activity in the aorta decreased after 4 weeks of HU.4. The data indicate that endothelium-dependent vasorelaxation in the abdominal aorta decreased due to 4 weeks of simulated microgravity in rats and that this impaired dilatory responsiveness may result from decreased NOS activity.