海带低分子量褐藻多糖硫酸酯对糖尿病肾病的治疗作用及机制研究

发布时间：2018-09-12 07:03

【摘要】：糖尿病肾病(DN)是糖尿病严重的微血管并发症之一,是慢性肾衰和终末期肾病的主要诱因之一,是导致糖尿病患者死亡的主要原因。DN作为糖尿病引起的代谢障碍并发症,其发生发展与多种病理过程有关。寻找治疗DN的有效药物,改善患者的生存质量迫在眉睫。低分子量褐藻多糖硫酸酯(LMWF)是从海带中制备的主要由岩藻糖和半乳糖组成的高度硫酸化的杂多糖。LMWF具有多种生物活性,包括抗凝血、抗炎症、抗血管生成、抗氧化、抗肿瘤和抗病毒等活性。多糖及糖复合物作为生命体的重要组成部分,在糖尿病肾病的发生和发展过程中起着重要作用。LMWF作为天然海藻硫酸多糖,很有可能通过对糖尿病肾病发生关键过程中的糖复合物的功能进行干预,抑制糖尿病肾病的发生和发展。本论文采用链脲佐菌素(STZ)诱导的糖尿病肾病模型,研究LMWF治疗糖尿病肾病的作用及其机制。⑴采用STZ诱导糖尿病肾病模型,DN大鼠出现典型的糖尿病肾病症状,尿微量总蛋白(M-TP)和尿白蛋白(u Alb)显著升高。LMWF灌胃给药能够阻止大鼠体重和尿量的减少,显著降低血液和尿液中的各项生化指标,减轻DN大鼠尿液中M-TP和u Alb的水平,减少蛋白尿的发生。减轻DN大鼠的肾脏损伤,保护和维持肾小球的基本结构及功能,进而缓解DN的发生发展。⑵炎症应答与DN的发生发展密切相关。苏木精-伊红(HE)染色显示LMWF能够保护DN大鼠肾脏正常的生理结构,缓解炎症反应和炎症细胞浸润水平。LMWF治疗组大鼠体内P-选择素和选择素依赖的炎症细胞因子的阳性表达不论是在转录水平还是蛋白水平都有明显的下调。表明LMWF能够减缓由P-选择素和炎症细胞因子所介导的炎症反应从而保护DN大鼠的肾脏功能。⑶肾小球基底膜(GBM)是实现肾小球滤过功能的重要元件,而硫酸乙酰肝素蛋白聚糖(HSPGs)是GBM的重要组成部分。乙酰肝素酶(HPSE)能够降解HSPGs中的硫酸乙酰肝素(HS)侧链,破坏肾小球的正常生理结构及功能。LMWF能够降低DN大鼠体内的糖胺聚糖的含量和晚期糖基化终末产物受体(AGER)的表达水平。LMWF还能够维持GBM和肾小球的结构完整性,进而改善肾小球的滤过功能,防止肾小球内的糖胺聚糖的不正常降解,抑制AGER的产生和累积对肾小球造成的损伤。并且,不论是在转录水平还是蛋白水平,LMWF能够下调HPSE及相关生长因子在DN大鼠体内的阳性表达。因此,本实验结果证实,LMWF能够通过抑制HPSE及相关生长因子的表达,维持肾小球的基本结构和功能,以此来缓解DN的发生发展。
[Abstract]:Diabetic nephropathy (DN) is one of the severe microvascular complications of diabetes mellitus, one of the main inducements of chronic renal failure and end-stage nephropathy, and the main cause of death of diabetic patients. DN is a metabolic disorder complication caused by diabetes mellitus. Its occurrence and development are related to various pathological processes. It is urgent to find effective drugs to treat DN and improve the quality of life of patients. Low molecular weight brown algae polysaccharide sulfate (LMWF) is a highly sulfated heteropolysaccharide, mainly composed of fucose and galactose, prepared from kelp. LMWF has a variety of biological activities, including anticoagulant, anti-inflammatory, anti-angiogenic, antioxidant. Antitumor and antiviral activities. As an important component of life, polysaccharide and carbohydrate complex play an important role in the occurrence and development of diabetic nephropathy. It is possible to inhibit the occurrence and development of diabetic nephropathy by interfering with the function of glucose complex in the key process of diabetic nephropathy. In this paper, the diabetic nephropathy model induced by streptozotocin (STZ) was used to study the effect of LMWF on diabetic nephropathy and its mechanism. 1 typical diabetic nephrotic symptoms were found in DN rats induced by STZ. Urinary total protein (M-TP) and urinary albumin (u Alb) were significantly increased. LMWF could prevent the decrease of body weight and urine volume, decrease the biochemical indexes in blood and urine, and reduce the levels of M-TP and u Alb in urine of DN rats. Reduce the incidence of proteinuria. Reducing renal injury in DN rats, protecting and maintaining the basic structure and function of glomeruli, and then alleviating the occurrence and development of DN. 2 inflammatory response is closely related to the occurrence and development of DN. Hematoxylin-eosin (HE) staining showed that LMWF could protect the normal physiological structure of kidney in DN rats. The positive expression of P- selectin and selectin-dependent inflammatory cytokines was significantly down-regulated at both transcription and protein levels in the LMWF treatment group. It is suggested that LMWF can attenuate the inflammatory response mediated by P- selectin and inflammatory cytokines and thus protect the renal function of DN rats. 3 glomerular basement membrane (GBM) is an important component in the realization of glomerular filtration function. Heparin sulfate proteoglycan (HSPGs) is an important component of GBM. Heparanase (HPSE) can degrade the side chain of heparin sulfate (HS) in HSPGs. Destroying the normal physiological structure and function of glomeruli. LMWF could decrease the content of glycosaminoglycan and the expression level of advanced glycosylation end product receptor (AGER) in DN rats. LMWF could also maintain the structural integrity of GBM and glomeruli. Furthermore, glomerular filtration function was improved, glycosaminoglycan in glomeruli was prevented from abnormal degradation, and AGER production and accumulation were inhibited. Furthermore, LMWF could down-regulate the expression of HPSE and related growth factors in DN rats, both at the transcriptional level and at the protein level. Therefore, it is confirmed that LMWF can maintain the basic structure and function of glomeruli by inhibiting the expression of HPSE and related growth factors, so as to alleviate the occurrence and development of DN.
【学位授予单位】：中国科学院研究生院(海洋研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R587.2;R692.9

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