食品中晚期糖基化终末产物的生物毒性评价

发布时间：2018-04-28 01:26

本文选题：晚期糖基化终末产物 + 羧甲基赖氨酸　；参考：《江南大学》2016年博士论文

【摘要】：晚期糖基化终末产物(Advanced glycation end products,AGEs)是还原糖(如葡萄糖)的活性羰基与蛋白质、脂肪以及核酸的自由氨基经非酶促反应形成的一系列结构稳定的化合物的总称。近年来,与体内AGEs水平相关的慢性疾病受到越来越多的关注。食物在热加工过程中产生大量AGEs,使得饮食成为体内AGEs的重要环境来源。目前关于外源性AGEs对生物体健康影响的研究不多且存在争议。因此本论文以AGEs的代表性生物标志物羧甲基赖氨酸(Nε?(Carboxymethyl)lysine,CML)纯品为研究材料,以健康成年大鼠和幼年大鼠为研究对象,探究CML对生物体健康的影响,以便明确评价外源性AGEs的生物毒性。首先,本论文系统考察了普通饮食条件下长期摄入游离态CML(60mg/kg体重/天)对健康成年SD大鼠组织的影响。研究发现大鼠各组织中结合态CML含量有所增加,其中肝脏、肾脏、心脏及肺中结合态CML含量增加显著(P0.05),脾脏和胰腺中结合态CML含量变化不明显;同时血清中尿素氮(blood urea nitrogen,BUN)、肌酸酐(creatinine,CREA)、谷丙转氨酶(alanine aminotransferase,ALT)及谷草转氨酶(aspartate aminotransferase,AST)水平显著升高(P0.05),证实大鼠肝肾功能受到损伤。不过大鼠的空腹血糖水平(fasting blood glucose,FBG)及能量消耗方面未受到明显影响。此外利用GC-TOF/MS技术对这些成年大鼠的血液和尿液进行了代谢组学分析,发现内源性代谢物3-羟基癸酸和胍基琥珀酸水平上升,进一步表明健康成年大鼠的肝肾功能发生了损伤;同时这些成年大鼠体内的能量代谢、碳水化合物代谢及氨基酸代谢也发生了紊乱。其次,本论文系统考察了高脂饮食条件下长期摄入游离态CML(60mg/kg体重/天)对健康成年SD大鼠组织的影响。研究发现大鼠主要组织(肾脏、心脏、肺、胰腺和肌肉)中结合态CML含量均有不同程度地增加,尤其是胰腺(与普通饮食相比);不过脾脏和肝脏中结合态CML含量无显著变化;同时大鼠FBG水平、血清低密度脂蛋白胆固醇(low-density lipoprotein cholesterol,LDL-C)及能量消耗水平均显著升高(P0.05)。首次提出了外源性游离态CML与组织中蛋白可能的结合方式是共价键结合。此外利用GC-TOF/MS技术对这些成年大鼠的血液和尿液进行了代谢组学分析,发现内源代谢物胍基琥珀酸水平上升、同时花生四烯酸水平下降,表明这些成年大鼠肾功能受损;甲硫氨酸亚砜水平的上升表明大鼠体内氧化应激水平升高;同时这些成年大鼠体内的氨基酸代谢及脂类代谢也发生了紊乱。最后,本论文系统考察了摄入添加不同剂量游离态CML(低剂量1.5g CML/kg饲料,中剂量4.5 g CML/kg饲料,高剂量13.5g CML/kg饲料)的普通饲料对健康幼年SD大鼠组织的影响。研究发现随着游离态CML摄入剂量的增加,大鼠各组织中结合态CML含量和尿蛋白含量呈剂量依赖性增加,血清总蛋白(total protein,TP)和白蛋白(albumin,ALB)水平以及肝脏脏器系数呈剂量依赖性下降,证实幼年大鼠肝肾功能受到影响;同时血液系统发生紊乱。不过幼年大鼠FBG水平及能量消耗方面未受到明显影响。此外利用GC-TOF/MS技术对摄入高剂量游离态CML的健康幼年大鼠的血液和尿液代谢物进行了代谢组学分析,发现高剂量组幼年大鼠的内源性代谢物乙酰-5羟色胺酸水平上升,表明这些幼年大鼠体内氧化应激水平升高;同时这些幼年大鼠体内的核苷酸代谢、氨基酸代谢、脂类代谢、辅因子及维生素代谢、碳水化合物代谢、转录及能量代谢等也发生了紊乱。基于以上研究结果,本论文认为普通饮食条件下长期摄入大量游离态CML会对健康大鼠的肝肾功能造成影响,尤其是成年大鼠肝肾功能会发生损伤;高脂饮食会影响健康成年大鼠的血糖水平,而大量游离态CML的摄入会加速血糖水平的上升。无论何种饮食,长期摄入大量游离态CML都会使健康大鼠体内的氧化应激水平升高,从而可能会对一系列慢性疾病的产生与发展(包括2型糖尿病)造成潜在风险。本论文的研究为人们了解长期摄入富含AGEs食品的潜在风险提供了基础理论参考,这对于人们改善不良的饮食习惯有积极的指导意义。
[Abstract]:Advanced glycosylation end products (Advanced glycation end products, AGEs) are a series of structural stable compounds formed by the active carbonyl of reducing sugar (such as glucose) and proteins, fat, and free amino groups of nucleic acids by non enzymatic reactions. In recent years, more and more attention has been paid to the chronic diseases associated with the level of AGEs in the body. Food produces a large number of AGEs during hot processing, making diet an important source of AGEs in the body. At present, there are few and controversial studies on the effects of exogenous AGEs on the health of organisms. Therefore, this paper uses AGEs's representative biomarker, carboxymethyl lysine (N? (Carboxymethyl) lysine, CML), as a research material. Healthy adult rats and young rats were studied to investigate the effects of CML on the health of the organisms so as to make a clear evaluation of the biological toxicity of exogenous AGEs. First, the effect of long intake of free CML (60mg/kg weight / day) on the tissues of healthy adult SD rats under normal diet was systematically investigated. The content of the binding state of CML in the liver, kidney, heart and lung increased significantly (P0.05), and the content of binding state CML in the spleen and pancreas was not significantly changed, and the serum urea nitrogen (blood urea nitrogen, BUN), creatinine (creatinine, CREA), alanine aminotransferase (alanine aminotransferase,) and glutamic aminotransferase were also found in the spleen and pancreas. Partate aminotransferase, AST) increased significantly (P0.05) and confirmed that the rat liver and kidney function was damaged. However, the fasting blood glucose level (fasting blood glucose, FBG) and energy consumption in rats were not significantly affected. In addition, the blood and urine of these adult rats were metabolized by GC-TOF/MS technique. The increased levels of 3- hydroxy decanic acid and guanidic succinic acid in the source metabolites further indicate that the liver and kidney function of healthy adult rats have been damaged, and the energy metabolism, carbohydrate metabolism and amino acid metabolism in these adult rats are also disturbed. Secondly, this paper examines the long-term intake of free diet under high fat diet. The effect of state CML (60mg/kg weight / day) on the tissue of healthy adult SD rats. It was found that the binding state CML content in the main tissues of the rats (kidney, heart, lung, pancreas and muscle) increased in varying degrees, especially in the pancreas (compared with the common diet), but there was no significant change in the CML content in the spleen and liver, and the level of FBG in rats. Serum low density lipoprotein cholesterol (low-density lipoprotein cholesterol, LDL-C) and energy consumption level were significantly increased (P0.05). It was first proposed that the combination of exogenous free CML and protein in tissue was covalent bond. In addition, the metabolic group of the blood and urine of these adult rats was carried out by GC-TOF/MS technology. It was found that the level of endogenous metabolite guanidic succinic acid increased and the level of four arachidic acid decreased, indicating that the renal function of these adult rats was impaired; the rise of methionine sulfoxide level indicated that the level of oxidative stress in the rats increased; at the same time, the metabolism of ammonia acid and lipid metabolism in these adult rats was also disturbed. Finally, In this paper, the effects of diet supplemented with different doses of free CML (low dose 1.5g CML/kg feed, medium dose of 4.5 g CML/kg feed and high dose 13.5g CML/kg feed) on the tissue of healthy young SD rats were investigated. The study found that with the increase of free CML intake dose, the binding state CML content and urine protein in the tissues of rats were added. The levels of the serum total protein (total protein, TP) and albumin (albumin, ALB) and the liver organ coefficient decreased in a dose-dependent manner. The liver and kidney function of young rats were affected, and the blood system was disturbed. However, the level of FBG and the energy consumption of young rats were not significantly affected. The metabolomics of blood and urine metabolites of healthy young rats with high dose of free CML was analyzed by GC-TOF/MS technique. The increase of endogenous metabolite acetyl -5 HT in young rats of high dose group showed that the levels of oxidative stress in these young rats increased; and the nucleus of these young rats Glucoside metabolism, amino acid metabolism, lipid metabolism, cofactor and vitamin metabolism, carbohydrate metabolism, transcription and energy metabolism have also been disturbed. Based on the above results, this paper suggests that a long intake of free CML in normal diet can affect the liver and kidney function of healthy rats, especially the liver and kidney of adult rats. A high fat diet may affect the level of blood sugar in healthy adult rats, while a large number of free CML intake will accelerate the rise of blood sugar levels. A diet and a long intake of free CML will increase the level of oxidative stress in healthy rats, which may produce and develop a series of chronic diseases. The research in this paper provides a basic theoretical reference for people to understand the potential risks of long term intake of AGEs foods, which has a positive guiding significance for people to improve their unhealthy dietary habits.

【学位授予单位】：江南大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R994.4

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