【作者】 刘立新；

【导师】 刘好文；

【作者基本信息】 河北医科大学 ， 神经病学， 2004， 硕士

【摘要】 目的: 2型糖尿病的发生，在国外占整个糖尿病比例的85%-95%，而国内报道亦在90%以上。因此，研制2型糖尿病的动物模型对其发病机制及其慢性并发症的研究具有重要的意义。目前国内糖尿病的研究多采用大剂量链尿菌素（streptozoticin STZ）（约60mg/kg）一次腹腔注射诱导的糖尿病大鼠模型，而该模型是一更类似于人类1型糖尿病的动物模型。在国外2型糖尿病的研究中，多采用遗传相关模型，但在这种模型中遗传因素起主导作用，这也不与临床相符。近20年来，随着对2型糖尿病发病机制研究的深入，我们逐渐认识到，2型糖尿病的发生是首先发生了胰岛素抵抗，然后胰岛功能失代偿，导致血糖升高即糖尿病发生。在这一理论的指导下，近几年我们建立了2型糖尿病的动物模型。本研究的目的在于：制备发病过程类似人类2型糖尿病的大鼠模型，并在不同的时期测定其坐骨神经电生理及腓肠神经和背根神经节的病理改变，以观察其周围神经病变特点，同时观察降糖药物对其电生理及病理改变的影响。方法: 用高糖高脂饲料喂养Wistar大鼠一月，诱导胰岛素抵抗，然后用亚致病剂量的STZ（约30mg/kg）腹腔注射，诱发高血糖。注射STZ后1个月，测定血糖和血浆胰岛素，<WP=4>根据血糖大于7.8mmol/L并伴有胰岛素敏感性降低这两个标准判断大鼠是否患有糖尿病，再将成膜的大鼠分为两组，糖尿病组和治疗组（给大鼠美吡达5mg/kg.d）,两组均继续喂以高糖高脂饲料（治疗组仍喂给高糖高脂饮食是以便更好地观察美吡达的作用），分别于注射STZ后1个月、注射后2个月、注射后4个月每组随机抽取一定数量的大鼠做肌电图观察电生理改变，并每组处死大鼠两只以观察腓肠神经及背根神经节的病理改变。结果: 1高糖高脂饲料喂养大鼠1个月后，大鼠血糖较常规饲料喂养组有所升高，但没达到糖尿病水平，并出现了高胰岛素血症和胰岛素抵抗、高脂血症；2注射STZ后，大鼠血糖升高，约1月后升高的血糖稳定（约为11.17±5.06mmol/L，常规饲料喂养组为4.06±0.29mmol/L,p<0.01），血浆胰岛素水平较STZ注射前有所降低，但仍较常规饲料喂养组为高（STZ注射组29.38±6.69uIU/ml,常规饲料喂养组为19.47±1.44 uIU/ml,p<0.05）,胰岛素抵抗和高血脂依然存在。3其神经病变特点：3.1电生理改变为糖尿病组大鼠坐骨神经运动潜伏速率、运动传导速度及动作电位的振幅均较常规饲料喂养组为低。其中运动潜伏速率为30.52±6.43m/s vs 45.5±5.00m/s,p<0.05，运动传导速度为39.66±8.21m/s vs 61.13±9.64m/s,p<0.05，动作电位波幅为20.50±5.74mv vs 32.67±7.55mv.p<0.05；3.2病理改变为糖尿病大鼠腓肠神经有髓神经纤维的数目、有髓神经纤维的总截面积和纤维数密度均较正常对照组减少。其中有髓神经纤维数目为110±25 vs 149±16,P<0.05，纤维总截面积为29423.96±5302.57 vs 40704.85±2068.00 p<0.01,纤维数密度为1573.40±356.99 vs <WP=5>2117.66±229.72 p<0.01。从腓肠神经锇酸染色的纵切面可看出有髓神经纤维有脱髓鞘改变。而背根神经节的神经细胞数目各组均无明显改变（可能与我们实验时间短有关）；4糖尿病大鼠应用降血糖药物美吡达后，血糖降低，坐骨神经运动潜伏速率、运动传导速度及动作电位的波幅均较糖尿病组明显改善，病理改变亦减轻。结论：1 Wistar 大鼠通过高糖高脂饲料喂养加小剂量STZ腹腔注射可成功诱导出2型糖尿病模型，成功率较高,约70%。2这种方法制备的动物模型具有中度高血糖、血浆胰岛素升高、胰岛素抵抗、高血脂等特点，是研究2型糖尿病及其各种慢性并发症的理想模型。3动物模型具有典型的周围神经病变特点：末梢神经运动潜伏速率及传导速度减慢，动作电位的波幅降低，末梢有髓神经纤维数目减少，神经纤维横截总面积和神经纤维数密度明显减少。4因条件所限我们的实验时间较短,但我们仍可看到应用降糖药物不仅可以降低血糖，而且可能对于减少糖尿病慢性并发症的发生或减轻糖尿病慢性并发症的程度起重要的作用。更多还原

【Abstract】 Objective: The incidence of type 2 diabetes mellitus is proportion 85%-90% of all diabetes in external.While in internal it has been reported over 90%. So ,It may have momentous significance for investigations of diabetic pathogenesis and chronic complications to develop the rat model of type 2 diabetes mellitus.At present,In internal the research of diabetes mostly adopt that a greatly dosage STZ(60mg/kg) intraperitoneal injection once to induce a rat model of diabetes.But this model closely simulates the human type 1 diabetes mellitus.In external,the reseach of diabetes mostly adopt a heredity model. But in this model the hereditary factor is a leading role. This does not agree with clinic. In recently 20 years , along with deepgoing of pathogenesis research of type 2 diabetes we gradually recognize that the happen of type 2 diabetes is a result of insulin resistance firstly ,then the function of pancreas will decompemsate and lastly haperglycemia is produced. In guiding of this theory , We build the rat model of type 2 diabetes in recent years.This study was aimed at developing a rat model that closely <WP=7>simulates the metabolic abnormalities of the human type 2 diabetes mellitus.In different period,we measure the electrophysiologic change of sciatic nerve and observe the pathologic developing of peripheral nerve .At the same time ,we observe the affection of the drug to electrophysiology and pathology.Methods：Female Wistar rats were fed with the diets enriched with sucrose(20% w/w) and lard (15% w/w) to induce insulin resistance. Hyperglycemia was developed by intraperitoned injection in these rats with 30mg/kg streptozotocin(STZ) after 1 month on the diets. After 1 month of STZ injection, Glucose and plasma insulin were measured. The rats were accepted as diabetic in the light of their blood glucose exceeded 7.8mmol/L after 1 month of STZ injection and their insulin sensitiveness dropped. Then , the model rats were divided into two groups: diabetes mellitus group and treatment group (the rats were fed with mindiab 5mg/kg. d). The two groups continue to feed with the diets enriched sucrose and lard. After 1, 2, 4 month of STZ injection , respectively, we ramdomly sample some rats in every group to observe the electrophysioloyic changes, and two rats of every group were put to death to observe the pathology developing of sutal nerve and dorsal root ganglion meurons.Results: 1 Blood glucose levels increased in response to diets but did not reach diabetes. Insulin levels increased <WP=8>and insulin resistance was confirmed, with hyperlipidemia. 2 After STZ injection hyperglycemia was developed, and after 1 month of STZ injection the hyperglycemia was steady [(11.17±5.06)mmol/L VS (4.06±0.29)mmol/L in controls,p<0.01] and plasma insulin decreased but was higher than the control [(29.38±6.69)ulu/ml vs (19.47±1.44)ulu/ml in controls, p<0.05]. Insulin resistance and hyperlipidemia still existed. 3 The characteristics of nerve system: 3.1 In those diabetic rats, the motor latent velocity and conduction velocity of sciatic nerve were slower, and the waves of action potential were lower than the controls [(30.52±6.43)m/s vs (45.5±5.00)m/s, p<0.05. (39.66±8.21)m/s vs (61.13±9.46)m/s ,p0.05. (20.50±5.74)mv vs (32.67±7.55)mv ,p<0.05.]. 3.2 Pathomophological study and compute image analysis of sural nerve and dorsal root ganglion .The number and area of myelin sheath, myelin sheath area percentage were smaller than the control group and treatment group[110±25 vs 149±16,p<0.05; 29423.96±5302.57 vs 40704.85±2068.00 p<0.01; 1573.40±356.99 vs 2117.66±229.72 p<0.01]. 4 Blood glucose of treatment group decreased , the motor latent velocities , conduction velocities and wave of action potential were improving , the---- pathological change was lighter than diabetes group.Conclusion: 1 The novel rat model which is similar to human type 2 diabetes is induced by way of feeding w更多还原