Chu Shuang, Mao Xiaodong, Guo Hengjiang, Wang Li, Li Zezheng, Zhang Yang, Wang Yunman, Wang Hao, Zhang Xuemei, Peng Wen
a Laboratory of Renal Disease , Putuo Hospital, Shanghai University of Traditional Chinese Medicine , Shanghai , China.
b Department of Nephrology , Putuo Hospital, Shanghai University of Traditional Chinese Medicine , Shanghai , China.
Free Radic Res. 2017 Mar;51(3):237-252. doi: 10.1080/10715762.2017.1296575. Epub 2017 Mar 13.
Accumulative indoxyl sulfate (IS) retained in chronic kidney disease (CKD) can potentiate vascular endothelial dysfunction, and herein, we aim at elucidating the underlying mechanisms from the perspective of possible association between reactive oxygen species (ROS) and RhoA/ROCK pathway. IS-treated nephrectomized rats are administered with antioxidants including NADPH oxidase inhibitor apocynin, SOD analog tempol, and mitochondrion-targeted SOD mimetic mito-TEMPO to scavenge ROS, or ROCK inhibitor fasudil to obstruct RhoA/ROCK pathway. First, we find in response to IS stimulation, antioxidants treatments suppress increased aortic ROCK activity and expression levels. Additionally, ROCK blockade prevent IS-induced increased NADPH oxidase expression (mainly p22phox and p47phox), mitochondrial and intracellular ROS (superoxide and hydrogen peroxide) generation, and decreased Cu/Zn-SOD expression in thoracic aortas. Apocynin, mito-TEMPO, and tempol also reverse these markers of oxidative stress. These results suggest that IS induces excessive ROS production and ROCK activation involving a circuitous relationship in which ROS activate ROCK and ROCK promotes ROS overproduction. Finally, ROS and ROCK depletion attenuate IS-induced decrease in nitric oxide (NO) production and eNOS expression levels, and alleviate impaired vasomotor responses including increased vasocontraction to phenylephrine and decreased vasorelaxation to acetylcholine, thereby preventing cardiovascular complications accompanied by CKD. Taken together, excessive ROS derived from NADPH oxidase and mitochondria coordinate with RhoA/ROCK activation in a form of positive reciprocal relationship to induce endothelial dysfunction through disturbing endothelium-dependent NO signaling upon IS stimulation in CKD status.
慢性肾脏病（CKD）中蓄积的硫酸吲哚酚（IS）可增强血管内皮功能障碍，在此，我们旨在从活性氧（ROS）与RhoA/ROCK通路之间可能的关联角度阐明其潜在机制。给接受IS治疗的肾切除大鼠给予抗氧化剂，包括NADPH氧化酶抑制剂阿朴吗啡、超氧化物歧化酶（SOD）类似物tempol和线粒体靶向SOD模拟物线粒体-TEMPO以清除ROS，或给予ROCK抑制剂法舒地尔以阻断RhoA/ROCK通路。首先，我们发现，响应IS刺激，抗氧化剂治疗可抑制主动脉ROCK活性和表达水平的升高。此外，阻断ROCK可防止IS诱导的NADPH氧化酶表达增加（主要是p22phox和p47phox）、线粒体和细胞内ROS（超氧化物和过氧化氢）生成以及胸主动脉中铜/锌-SOD表达降低。阿朴吗啡、线粒体-TEMPO和tempol也可逆转这些氧化应激标志物。这些结果表明，IS诱导过量的ROS产生和ROCK激活，二者存在一种循环关系，即ROS激活ROCK，而ROCK促进ROS的过量产生。最后，ROS和ROCK的减少可减轻IS诱导的一氧化氮（NO）产生和内皮型一氧化氮合酶（eNOS）表达水平的降低，并减轻血管运动反应受损，包括对去氧肾上腺素的血管收缩增加和对乙酰胆碱的血管舒张降低，从而预防CKD伴发的心血管并发症。综上所述，在CKD状态下，IS刺激时，源自NADPH氧化酶和线粒体的过量ROS与RhoA/ROCK激活以正反馈关系协同作用，通过干扰内皮依赖性NO信号传导诱导内皮功能障碍。
