糖尿病膀胱逼尿肌氧化应激损伤中Nrf2通路的保护作用及其机制研究

The incidence of diabetes is ever-increasing and diabetic cystopathy (DCP) is the most common urinary complication of diabetes. Results from recent studies indicate that the oxidative damage to detrusor is an important pathogenesis of diabetic cystopathy. Meanwhile, Nuclear erythroid 2-related factor 2(Nrf2) is a key transcriptional factor for regulation of oxidative stress in vivo. Fortunately, we have found that Nrf2 was significantly up-regulated in the detrusor of streptozotocin (STZ)-induced diabetic mice, which suggest that Nrf2 pathway may play a positive role against the oxidative damage in detrusor. The aim of our study is to investigate the mechanism of the protective role of Nrf2 pathway against oxidative damage in detrusor. The assessment of damage in the detrusor of STZ-induced diabetic mice will be made by urodynamic test, and the detection of the expression of Nrf2 and its downstream factors in DCP tissues also will be performed. Furthermore，the protective effect will be comfirmed in Nrf2-/- mice and activator sulforaphane-treated mice. In a word, this research is designed to explore the protective role of Nrf2 signal pathway against oxidative damage in vivo and identify the efficacy of sulforaphane on the treatment of DCP.

糖尿病发病率日益升高，糖尿病膀胱是其重要并发症之一。研究表明逼尿肌氧化应激损伤是糖尿病膀胱的重要发病机制，而转录因子NF-E2相关因子2（Nrf2）是机体抗氧化应激关键因子。我们前期研究发现，Nrf2在糖尿病小鼠膀胱逼尿肌表达上调，提示Nrf2通路可能参与保护糖尿病膀胱逼尿肌氧化应激损伤。本课题首次针对Nrf2通路在糖尿病膀胱逼尿肌氧化应激损伤中的作用及机制开展研究，通过建立糖尿病小鼠模型，从形态学及功能学角度评估膀胱损害程度，分析Nrf2表达、核转位及其下游蛋白的表达差异；进一步借助Nrf2基因敲除小鼠造成Nrf2缺失，引入诱导剂莱菔硫烷处理造成Nrf2高表达，并验证上述改变，以此证实Nrf2通路对糖尿病膀胱逼尿肌氧化应激损伤的保护作用。在此基础上进一步探讨莱菔硫烷对糖尿病膀胱氧化应激损伤的保护作用及其机制，所获结果有望进一步阐明糖尿病膀胱的发病机制，为防治糖尿病膀胱提供线索和理论依据。

糖尿病发病率日益升高，糖尿病膀胱是其重要并发症之一。研究表明逼尿肌氧化应激损伤是糖尿病膀胱的重要发病机制，而转录因子NF-E2相关因子2（Nrf2）是机体抗氧化应激关键因子，越来越多的研究关注Nrf2通路在糖尿病及其并发症中的作用及其相关机制。本课题针对Nrf2通路在糖尿病膀胱逼尿肌氧化应激损伤中的作用及机制开展研究，通过建立野生型小鼠及Nrf2基因敲除小鼠糖尿病模型，从形态学及功能学角度评估膀胱损害程度，发现Nrf2基因敲除小鼠可出现更为严重膀胱功能损害，表现为膀胱收缩力更低下，膀胱残余尿更多；同时组织氧化应激损伤也更明显，形态学上可发现逼尿肌纤维排列更为稀疏紊乱。进一步行RT-PCR和Western Blot，我们发现Nrf2及其下游蛋白在糖尿病小鼠膀胱逼尿肌表达协同上调，提示Nrf2通路参与并通过调控下游抗氧化蛋白干预糖尿病膀胱逼尿肌氧化应激损伤；我们进一步使用Nrf2诱导剂莱菔硫烷处理糖尿病小鼠，探讨莱菔硫烷对糖尿病膀胱氧化应激损伤的保护作用，我们发现，莱菔硫烷可改善糖尿病小鼠膀胱收缩力，促进膀胱排空，缓解膀胱组织氧化应激损伤，防止逼尿肌细胞损害，进一步检测发现Nrf2及其下游蛋白表达明显高于对照组，SFN可能通过诱导激活Nrf2通路，调控下游抗氧化蛋白发挥抗氧化作用。由此，我们的研究记过证实了Nrf2通路对糖尿病膀胱逼尿肌氧化应激损伤的保护作用，所获结果进一步阐明了糖尿病膀胱的发病机制，为防治糖尿病膀胱提供线索和理论依据。