锌对糖尿病视网膜病变的保护作用

发布时间：2019-06-29 12:08

【摘要】：锌是一种金属化学元素,广泛存在于自然界中。同时,锌离子是人体必需的金属离子之一,能参与体内微环境的稳态调节、免疫调节、氧化应激响应、凋亡过程、老化等等。动物实验证明,锌能促进抗氧化剂金属硫蛋白(metallothionein, MT)生成增加,互相作用,使机体的抗氧化能力提高；能与铜离子共同形成铜／锌超氧岐化酶(Cu/Zn SOD)发挥其抗氧化作用;能稳定核因子E2相关因子2(nuclear factor erythroid-2related factor2, Nrf2)的结构,使其在体内蛋白含量增加,功能性增加,从而调控下游的多种抗氧化基因水平,如醌氧化还原酶1(NQ01),第一型血色素氧化酵素(HO-1),超氧岐化酶1、2(SOD1, SOD2)等等,激活机体的多种抗氧化机制。糖尿病是一种常见病、多发病,以其高发病率、高致死率严重影响人们的生活质量而被广泛关注。随着病情的发展,能诱发多种严重的并发症,其并发症主要分两大类,即糖尿病大血管并发症如糖尿病大血管病变、动脉粥样硬化；糖尿病微血管并发症如糖尿病心肌病,糖尿病肾脏病,糖尿病视网膜病变等等,很多报道指出,氧化应激损伤对糖尿病以及其并发症的发生与发展负有不可推卸的责任。众所周知,糖尿病能引起机体血糖增高,代谢系统紊乱。这会导致组织器官炎症反应,氧化应激水平增高,氧化应激产物活性氧自由基(ROS)、活性氮自由基(RNS)产生增多,在组织器官中的累积也相应增多。它会攻击机体的组织器官、血管内皮细胞,产生一系列的损伤反应,例如炎症、纤维化、凋亡等等。流行病学报道指出,糖尿病患者血清锌离子含量降低。而外源性的补锌,能使血清中锌离子含量增高,而产生抗氧化作用。基于此,我们设计了如下实验,意在探究补锌对糖尿病引起的血管并发症(以大血管为中心)、微血管并发症(以糖尿病视网膜病变为中心)的保护作用,及其可能机制。我们首先建立了C57/6小鼠高脂喂养6个月的动物模型,检测代谢综合征时期,视网膜的病理学改变。结果表明,早在代谢综合征时期,视网膜就已经出现相应的炎症反应增高,氧化应激水平增高,抗氧化物质代偿性增高等改变。同时,与我们猜测一致,部分炎症反应因子、抗氧化物质的增高集中体现在血管周围,这暗示血管损伤是糖尿病引起的主要损伤和首发损伤。所以,我们进一步应用自发Ⅰ型糖尿病转基因小鼠OVE26建立了锌补充6个月的糖尿病模型。结果表明,补锌对糖尿病引起的血管并发症有明显的保护和预防作用。无论是6个月时的糖尿病血管损伤还是补锌的保护作用都没有性别差异。同时,我们也观察到,补锌能使血管管壁中MT以及Nrf2的表达以及功能增高(其下游抗氧化基因表达增高),这暗示着补锌所引起的糖尿病血管损伤的保护作用可能是由于上调MT和Nrf2的表达及功能引起。Nrf2是生物体内重要的抗氧化物质,所以我们进一步探讨了Nrf2的预防与治疗作用。我们分别应用了经典的糖尿病模型(STZ模型)与自发Ⅰ型糖尿病模型(OVE26小鼠)给予不同的Nrf2的激动剂——萝卜硫素(sulforaphane, SFN)和蛋白酶体抑制剂(MG132),探讨Nrf2的预防与治疗作用。结果表明,SFN对糖尿病血管损伤有预防作用,这种预防作用是通过上调Nrf2引起的。并且,SFN的作用不仅仅在于给药过程中,这种影响在停药后的三个月仍呈现出较高水平,而对糖尿病引起的血管损伤提供持续的保护和预防作用。MG132能抑制Nrf2降解,增强其功能,对糖尿病引起的血管损伤有明显的治疗作用。即使开始用药时,糖尿病小鼠已经出现明显的蛋白尿,血管也已经显示出明显的炎症、氧化应激等病理学损伤,给予MG132三个月后,这种损伤响应基本被完全治愈,并且预防和延缓了糖尿病血管损伤的发展。综合上述两部分研究说明,上调Nrf2的表达与功能,对糖尿病引起的血管损伤有明显的预防与治疗作用。本研究通过建立多种糖尿病并发症模型,使用多种物质干预,利用免疫组织化学染色及real-time PCR的方法,在动物研究中,证明了糖尿病视网膜病变是以糖尿病引起的血管损伤为首要发病因素的疾病,补锌对糖尿病引起的血管损伤有预防和保护作用,可能的原因是外源补充的锌离子上调了内生的抗氧化系统,如MT, Nrf2的表达和功能。这为治疗和预防糖尿病并发症的发生发展提供了新的思路；同时也为补锌能预防治疗糖尿病视网膜病变的基础与机制研究提供了新的依据。
[Abstract]:Zinc is a kind of metal chemical element, which is widely present in nature. At the same time, the zinc ion is one of the necessary metal ions in the human body, and can participate in the steady state regulation, the immunoregulation, the oxidative stress response, the apoptosis process, the aging and the like of the in vivo microenvironment. The results of animal experiments show that zinc can promote the formation of metallothionein (MT) and increase the anti-oxidation ability of the body. The copper/ zinc superoxide dismutase (Cu/ Zn SOD) can be formed by co-forming the copper/ zinc superoxide dismutase (Cu/ Zn SOD) with the copper ions. the structure of the nuclear factor E2 related factor 2 (Nrf2) can be stabilized, so that the protein content in the body is increased, the function is increased, and a plurality of anti-oxidation gene levels downstream, such as the oxidoreductase 1 (NQ01), the first type blood pigment oxidation enzyme (HO-1) and the superoxide dismutase 1,2 (SOD1, SOD2) and the like, activate various antioxidant mechanisms of the body. Diabetes is a common disease, it is a common disease, with its high morbidity and high mortality, it is widely used to influence the quality of life. Note: With the development of the disease, many serious complications can be induced, and the complications are mainly divided into two categories, namely, diabetic macrovascular complications such as diabetic macroangiopathy, atherosclerosis, diabetic microangiopathy such as diabetic cardiomyopathy, diabetic kidney, Many reports indicate that oxidative stress damage has an unshirkable responsibility for the occurrence and development of diabetes and its complications, according to a number of reports. It is well known that diabetes can cause an increase in blood glucose and a metabolic system in the body. This can lead to the inflammatory reaction of the tissue organ, the level of oxidative stress, the reactive oxygen free radical (ROS) of the oxidative stress product, the increase of the active nitrogen free radical (RNS) and the corresponding increase in the accumulation of the tissue organ. It will attack the body's tissue organs, vascular endothelial cells, and produce a series of damage reactions, such as inflammation, fibrosis, apoptosis, etc. Et al. The epidemiological report indicates that the serum zinc ion content in patients with diabetes is reduced. Low, and exogenous zinc supplement, can increase the content of zinc ion in the serum, and produce anti-oxidation. With this, we have designed the following experiments to explore the protective effect of zinc-supplementing on the vascular complications caused by diabetes (with large blood vessels as the center), microvessel complications (with diabetic retinopathy as the center), and the possible machines Methods: We first established the animal model of 6-month high-fat feeding of C57/6 mice to detect the pathological conditions of the metabolic syndrome and the pathology of the retina. The results showed that, in the period of metabolic syndrome, the corresponding inflammatory reaction of the retina was increased, the level of oxidative stress increased, and the compensatory increase of the anti-oxidation substance was increased. At the same time, with our guesses, some of the inflammatory response factors and the increase in the antioxidant substance are concentrated around the blood vessel, suggesting that the vascular injury is the main lesion and the head caused by diabetes. So, we used the spontaneous type I diabetic transgenic mouse OVE26 to set up zinc for 6 months of glycosuria. The results show that the zinc supplement has obvious protection and pre-treatment for vascular complications caused by diabetes. It has no sexual function, no matter whether the diabetic vascular injury or the protective effect of zinc supplement at 6 months has no sex. At the same time, we have also observed that zinc supplementation can increase the expression and function of MT and Nrf2 in the vessel wall, which suggests that the protective effect of zinc supplementation on diabetic vascular injury may be due to the up-regulation of the expression and work of MT and Nrf2. Nrf2 is an important antioxidant in the organism, so we further explore the prevention and treatment of Nrf2. We applied the classic diabetes model (STZ model) and the spontaneous type I diabetes model (OVE26 mouse) to give different Nrf2 agonist _ radish (SFN) and proteasome inhibitor (MG132) to explore the prevention and treatment of Nrf2. The results show that SFN has a preventive effect on diabetic vascular injury, and the prevention effect is to increase Nrf2 by up-regulation of Nrf2. and the effect of the sfn is not only in the course of administration, but this effect remains high in the three months after the withdrawal, while providing continuous protection and pre-treatment of the vascular damage caused by diabetes Anti-action. MG132 can inhibit Nrf2 degradation, enhance its function, and have obvious treatment for vascular injury caused by diabetes The effect of the treatment is that, even when the medicine is started, the diabetic mice have obvious proteinuria, and the blood vessels have shown obvious inflammation, oxidative stress and other pathological damage, and after the MG132 is given for three months, the damage response is basically completely cured, and the vascular injury of the diabetes is prevented and delayed. The development of the two-part study indicated that up-regulation of the expression and function of Nrf2 and the prevention and treatment of vascular injury caused by diabetes In this study, by establishing a variety of diabetic complication models and using a variety of substance interventions, the method of immunohistochemical staining and real-time PCR was used to prove that diabetic retinopathy was the first type of vascular injury caused by diabetes. The disease of the factor, zinc supplement has the effect of preventing and protecting the blood vessel damage caused by diabetes, and the possible cause is that the externally-supplemented zinc ion upregulates the endogenous anti-oxidation system, such as MT, Nrf2. Expression and function. This provides a new way for the treatment and prevention of the development of diabetic complications, and also provides the basis and mechanism for the prevention and treatment of diabetic retinopathy.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R587.2;R774.1

【共引文献】