Ramipril treatment protects against nitrate-induced oxidative stress in eNOS-/- mice:: An implication of the NADPH oxidase pathway
Ramipril treatment protects against nitrate-induced oxidative stress in eNOS-/- mice:: An implication of the NADPH oxidase pathway
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DOI：
10.1097/01.fjc.0000238587.68239.52
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发表时间：
2006-07-01
影响因子：
3
通讯作者：
Berkenboom, Guy
中科院分区：
文献类型：
--
作者：
Otto, Anne;Fontaine, Jeanine;Berkenboom, Guy
已发现硝酸盐耐受性的发展与主要由eNOS和NADPH氧化酶途径产生的超氧阴离子（O-2（-中心点））的血管产生相关。本研究的目的是探讨雷米普利对血管紧张素转换酶的长期抑制是否能够保护eNOS缺陷型（eNOS（-/-））小鼠的血管紧张素转换酶对硝酸盐的耐受性，并评估NADPH氧化酶途径的影响。因此，对野生型（WT）和eNOS（-/-）小鼠给予3种类型的治疗：第1组接受雷米普利5周，并在最后4天与雷米普利加硝酸甘油（NTG）联合治疗，第2组仅接受NTG，第3组作为对照。NTG（0.1 nmol/L至0.1 mmol/L）的舒张作用在U44619上测定，U44619是一种血栓烷类似物，预收缩环和O-2-（中心点）的产生用光泽精增强化学发光技术在主动脉匀浆上进行评估。环磷酸鸟苷和逆转录酶-聚合酶链反应分析进行了整个小鼠睾丸。在WT组2中，NTG的浓度-效应曲线显著右移：pD（2）为6.16 +/- 0.17（n = 6）vs 6.81 +/- 0。WT组3（未暴露于NTG; P < 0.05）中O-10（n = 6）和O-2（-中心点）的产生从100% +/-11%（n = 9）增加到191% +/-21%（n = 6; P < 0.01）。相比之下，在WT 1组中，pD（2）值为6.73 +/- 0.13（n = 6; NS vs组3 WT），O-2（-中心点）产量为117% +/- 6%（n = 7; NS vs组3 WT）。在eNOS（-/-）组1和3中，观察到类似的数据：pD（2）值分别为7.58 +/- 0.08和7.38 +/- 0.11（NS）vs eNOS（-/-）组2中的6.89 +/- 0.20（n = 6; P < 0.01）。在野生型小鼠胸腺中，雷米普利治疗显著增加了环磷酸鸟苷水平（反映了一氧化氮的可用性），在体内与缓激肽BK 2拮抗剂（伊卡替班）共同治疗后，其恢复到对照值。在这两种菌株中，坎地沙坦，一种AT I阻断剂，也能够防止硝酸盐耐受性的发展。此外，在NTG暴露之前，雷米普利处理降低了两种小鼠品系的睾丸中p22 phox和gp 91 phox（必需NADPH氧化酶亚基）mRNA的表达。总之，长期雷米普利治疗小鼠通过抵消NTG诱导的O-2（-中心点）产生的增加来防止硝酸盐耐受性的发展，这涉及与NADPH氧化酶途径的直接相互作用，并且似乎完全独立于cNOS途径。
The development of nitrate tolerance has been found to be associated with vascular production of superoxide anion (O-2(-center dot)), generated mainly by the eNOS and NADPH oxidase pathways. The aim of our study was to investigate whether long-term angiotensin-converting enzyme inhibition by ramipril is able to protect against nitrate tolerance in the aortas of eNOS-deficient (eNOS(-/-)) mice and to assess the implication of the NADPH oxidase pathway. Therefore, 3 types of treatment-were given to wild-type (WT) and eNOS(-/-) mice: group 1 received ramipril for 5 weeks and a co-treatment with ramirpil plus nitroglycerine (NTG) during the last 4 days, group 2 received only NTG, and group 3 served as control. Relaxations to NTG (0.1 nmol/L to 0.1 mmol/L) were determined on U44619, a thromboxane analogue, precontracted rings, and O-2-(center dot) production were assessed on aorta homogenates with the lucigenin-enhanced chemiluminescence technique. Cyclic guanosine monophosphate and reverse-transcriptase-polymerase chain reaction analyses were performed on whole mouse aortas. In WT group 2, the concentration-effect curves to NTG were significantly shifted to the right: the pD(2) was 6.16 +/- 0.17 (n = 6) vs 6.81 +/- 0. 10 (n = 6) in WT group 3 (not exposed to NTG; P < 0.05) and O-2(-center dot) production was enhanced from 100% +/- 11% (n = 9) to 191% +/- 21% (n = 6; P < 0.01). In contrast, in WT group 1, the rightward shift was abolished: the pD(2) value was 6.73 +/- 0.13 (n = 6; NS vs group 3 WT) and O-2(-center dot) production was 117% +/- 6% (n = 7; NS vs group 3 WT). In eNOS(-/-) groups 1 and 3, similar data were observed: the pD(2) values were 7.58 +/- 0.08 and 7.38 +/- 0.11 (NS) vs 6.89 +/- 0.20 in eNOS(-/-) group 2 (n = 6; P < 0.01). In the WT mice aortas, ramipril treatment significantly increased the cyclic guanosine monophosphate levels (reflecting nitric oxide availability), which returned to control values after in vivo co-treatment with a bradykinin BK2 antagonist (Icatibant). In both strains, candesartan, an AT I blocker, was also able to protect against the development of nitrate tolerance. Moreover, before NTG exposure, ramipril treatment decreased p22phox and gp91phox (essential NADPH oxidase subunits) mRNA expression in aortas from both mice strains. In conclusion, long-term ramipril treatment in mice protects against the development of nitrate tolerance by counteracting NTG-induced increase in O-2(-center dot) production, which involves a direct interaction with the NADPH oxidase pathway and seems to be completely independent of the cNOS pathway.