醛糖还原酶抑制剂改善链脲佐菌素引起的AD样病变及其机制研究

发布时间：2018-05-15 15:18

本文选题：AD + STZ　；参考：《华中科技大学》2013年硕士论文

【摘要】：研究背景阿尔茨海默病（Alzheimer's disease, AD）是导致老年人群痴呆最重要的原因，其特征性的病理改变为聚集于神经细胞外的老年斑（Senile plaque，SP）和细胞内的神经原纤维缠结（Neurofibrillary tangle, NFT）以及进行性的学习记忆障碍。糖尿病患者AD发病危险性比普通人群明显升高，且糖尿病可通过多种途径引起神经元病理和认知功能损伤。随着老化和糖代谢失调，多元醇通路和醛糖还原酶（Aldose reductase, AR）明显激活，但AR是否参与AD病理过程以及抑制AR活性能否改善AD相关的神经病理改变目前仍不清楚。目的探讨醛糖还原酶抑制剂是否能改善链脲佐菌素（Streptozotocin, stz）引起的AD样病理改变及其可能的机制。材料与方法为探讨醛糖还原酶抑制剂对stz引起的AD样病变的影响极其作用机制，我们选用3月龄Sprague Dawley（SD）大鼠（体重约为300±30g）进行双侧脑室注射stz（Intracerebroventricular-streptozotocin, icv-stz,3mg/kg）建立AD样动物模型。造模成功后根据分组用不同的试剂对实验动物进行连续3周的灌胃处理。实验动物分为四组，分别为：（1）空白对照组，侧脑室注射人工脑脊液，生理盐水灌胃；（2）stz组，侧脑室注射stz，生理盐水灌胃；（3）stz+zop组，，侧脑室注射stz，醛糖还原酶抑制剂zopolrestat灌胃（50mg/kg·day）；（4）stz+sob组，侧脑室注射stz，醛糖还原酶抑制剂sorbinil灌胃（25mg/kg·day）；每组动物数量均为8-10只。模型建立一月后用免疫印迹法检测动物海马tau蛋白磷酸化程度和tau蛋白磷酸化相关蛋白激酶表达水平，用试剂盒检测相应脑区组织细胞氧化应激相关指标超氧化物歧化酶（Superoxide Dismutase, SOD）活力和丙二醛（MaleicDialdehyde, MDA）含量，并用Morris水迷宫实验评估动物的空间学习记忆能力。结果 1.醛糖还原酶抑制剂改善stz引起的空间记忆能力障碍。水迷宫实验表明，侧脑室注射stz不影响大鼠空间学习能力，但严重损害大鼠空间记忆能力；醛糖还原酶抑制剂显著改侧脑室注射stz引起的空间记忆障碍。 2.醛糖还原酶抑制剂降低stz诱导的tau蛋白过度磷酸化。免疫印迹结果表明，侧脑室注射stz引起大鼠海马tau蛋白多个位点磷酸化程度加强，醛糖还原酶抑制剂降低icv-stz大鼠海马tau蛋白在这些位点的磷酸化水平。 3.醛糖还原酶抑制剂通过丝裂原活化蛋白激酶（mitogen-activated protein kinase,MAPK）途径改善stz引起的AD样病变。免疫印迹结果显示，侧脑室注射stz引起大鼠海马MAPK途径的C-Jun基末端激酶（C-Jun N-terminal kinase, JNK）和激活细胞外调节蛋白激酶（extracellular regulated protein kinase, ERK1/2）磷酸化水平升高，提示其活性增强；两种醛糖还原酶抑制剂则不同程度地减弱上述激酶的磷酸化程度。此外，stz组大鼠海马糖原合酶激酶-3（glycogen synthase kinase-3, GSK-3）在serine9位点磷酸化程度加强，提示其活性减弱，说明侧脑室注射stz可能不通过GSK-3影响tau蛋白磷酸化。 4.氧化应激不参与stz引起的大鼠AD样病理改变。模型建立后一个月，与对照组相比，stz组大鼠脑部SOD活力和MDA含量均无显著差异，说明侧脑室注射stz此时并不引起大鼠脑部氧化应激，stz诱导的AD样病变可能不是由氧化应激介导的。此外，醛糖还原酶抑制剂对大鼠脑部SOD活力和MDA含量亦无影响。结论 1.醛糖还原酶抑制剂对stz诱导的AD样病变有改善作用。 2.醛糖还原酶可能通过MAPK通路改善stz诱导的AD样病变。
[Abstract]:Research background
Alzheimer's disease (AD) is the most important cause of dementia in the elderly. Its characteristic pathological changes are the senile plaque (Senile plaque, SP) and the intracellular neurofibrous tangles (Neurofibrillary tangle, NFT) and progressive learning and memory disorders. The pathogenesis of diabetes mellitus patients is AD. The risk is significantly higher than that of the general population, and diabetes can cause pathological and cognitive impairment of neurons through a variety of pathways. With aging and disorder of glucose metabolism, the polyol pathway and aldose reductase (Aldose reductase, AR) are obviously activated, but whether AR participates in the pathological process of AD and whether the inhibition of AR activity can improve the neuropathology of AD related neuropathology. The change is still unclear.
objective
To investigate whether aldose reductase inhibitors can improve the AD like pathological changes induced by Streptozotocin (STZ) and its possible mechanism.
Materials and methods
In order to investigate the effect of aldose reductase inhibitor on AD like lesions caused by STZ, we selected 3 month old Sprague Dawley (SD) rats (weight about 300 + 30g) to establish AD like animal models by injecting STZ (Intracerebroventricular-streptozotocin, ICV-STZ, 3mg/kg) into bilateral ventricles of the brain (Intracerebroventricular-streptozotocin, ICV-STZ, 3mg/kg). The experimental animals were divided into four groups for 3 weeks. The experimental animals were divided into four groups: (1) blank control group, lateral ventricle injection of artificial cerebrospinal fluid, saline irrigation, group STZ, lateral ventricle injection of STZ, saline irrigation; (3) stz+zop, lateral ventricle injection of STZ, aldose reductase inhibitor zopolrestat gavage (50mg/kg day) (4) group stz+sob, side ventricle injection of STZ, aldose reductase inhibitor Sorbinil gavage (25mg/kg. Day), each group of animals were 8-10. After a month, the model was established by immunoblotting to detect the degree of phosphorylation of tau protein and the expression level of phosphorylation related protein kinase of tau protein in animal hippocampus, and the corresponding brain tissue cells were detected by the kit. The activity of Superoxide Dismutase (SOD) and the content of malondialdehyde (MaleicDialdehyde, MDA) were measured by oxidative stress, and the spatial learning and memory ability of animals was evaluated by the Morris water maze test.
Result
1. aldose reductase inhibitor improved the spatial memory ability disorder caused by STZ. The water maze test showed that the injection of STZ in the lateral ventricle did not affect the spatial learning ability of the rats, but seriously damaged the spatial memory ability of the rats, and the aldose reductase inhibitor significantly altered the spatial memory impairment caused by the injection of STZ in the lateral ventricle.
2. aldose reductase inhibitor reduced the excessive phosphorylation of tau protein induced by STZ. The results of immunoblotting showed that the degree of phosphorylation of multiple sites of tau protein in hippocampus of rats was enhanced by injection of STZ in the lateral ventricle, and the phosphorylation level of tau protein at these sites was reduced by aldose reductase inhibitor in ICV-STZ rats.
3. aldose reductase inhibitors improve AD like lesions caused by STZ through the mitogen activated protein kinase (mitogen-activated protein kinase, MAPK) pathway. The immunoblotting results showed that the injection of STZ in the lateral ventricle caused the C-Jun base kinase (C-Jun N-terminal kinase,) and the activation of extracellular regulated protein kinase in the hippocampal MAPK pathway of the rat. Acellular regulated protein kinase, ERK1/2) increased the phosphorylation level, suggesting that the activity of the two aldose reductase inhibitors decreased the degree of phosphorylation of the above kinase to varying degrees. In addition, the phosphorylation of glycogen synthase kinase -3 (glycogen synthase kinase-3, GSK-3) in the hippocampus of the STZ group was enhanced, suggesting that the degree of phosphorylation in the loci was enhanced. Its activity decreased, suggesting that STZ injected into the lateral ventricle might not affect the phosphorylation of tau protein through GSK-3.
4. oxidative stress did not participate in AD like pathological changes in rats induced by STZ. One month after the establishment of the model, there was no significant difference in the activity of SOD and the content of MDA in the brain of the rats of the control group, indicating that the lateral ventricle injection of STZ did not cause oxidative stress in the rat brain at this time, and the AD like lesion induced by STZ may not be mediated by oxidative stress. In addition, the aldehyde group was not induced by oxidative stress. There was no effect of sugar reductase inhibitor on SOD activity and MDA content in brain of rats.
conclusion
1. aldose reductase inhibitors can improve AD induced lesions induced by STZ.
2. aldose reductase may improve the STZ induced AD like lesion through the MAPK pathway.

【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R749.16

【共引文献】