链脲佐菌素型糖尿病模型大鼠股骨头坏死的血脂、凝血代谢及组织病理学变化

背景：糖尿病性股骨头坏死的病理机制和病变特征至今尚未阐明。有研究证实，骨坏死与低纤溶状态有关，高脂血症是引起股骨头缺血性坏死的重要诱因。 目的：拟观察糖尿病股骨头缺血性坏死模型大鼠的血脂、凝血代谢及组织病理学变化。 设计、时间及地点：随机对照动物实验，于2006-04/2007-10在西安交通大学医学院第二附属医院骨科教研室及西安交通大学医学院病理教研室完成。 材料：选用12周龄SD大鼠100只，适应性喂养2周后，精确称重，按性别抽取24只(雌雄各半)作为空白对照组，其余76只行速发型糖尿病大鼠模型制备。 方法：模型组大鼠将60 mg/kg链脲佐菌素腹腔快速推入，建立速发型糖尿病大鼠模型，使动物进食及饮水时双后腿负重，模拟人类髋关节生理状态。对照组24只给予腹腔针刺，不注入任何液体。 主要观察指标：两组大鼠分别于造模成功后第4，8，12，18周麻醉后分批处死，对照组每次随机处死6只，模型组每次处死18只，进行大体形态、组织病理学、血脂及凝血指标检测。 结果：造模成功后模型组大鼠日渐消瘦，食欲旺盛，饮水量增加，体质量逐渐下降。模型组大鼠电镜下均可见骨小梁表面成骨细胞减少，活性降低；光镜下观察，与同期对照组比较，自造模第4周后空骨陷窝计数显著增加(P < 0.01)。与同期对照组相比，模型组大鼠造模后第8，12，18周活化部分凝血活酶时间、凝血酶原时间及凝血酶时间显著缩短(P < 0.05~0.01)，纤维蛋白原水平显著升高 (P < 0.05~0.01)，血清总胆固醇、三酰甘油浓度显著升高(P < 0.01)，高密度脂蛋白显著降低 (P < 0.05~0.01)。 结论：糖尿病可引起长期骨质疏松、高脂血症、血液高凝状态，这些因素共同作用下将会最终导致糖尿病股骨头缺血性坏死的发生。     

链脲佐菌素剂量对C57BL/6J小鼠糖尿病神经病理性疼痛诱导效应的影响

目的观察不同剂量链脲佐菌素(STZ)对C57BL/6J小鼠糖尿病神经病理性痛诱导效应的影响,探讨其量效关系及最佳剂量。方法雄性C57BL/6J小鼠85只,随机分为正常对照组(n=10)和A～E 5个实验组(n=15,STZ腹腔注射剂量分别为80、100、120、140、160mg/kg),对照组腹腔注射等体积柠檬酸缓冲液。观察各组血糖、机械痛阈值、热刺痛阈值和28d生存率的变化,分析其与STZ剂量的关系。结果 A～E各组糖尿病成模率均>86.7%。C组神经病理性疼痛成模率(66.7%)均高于其余各组;E组28d生存率(46.7%)与A、B组间均存在显著差异(P<0.05)。结论 C57BL/6J小鼠腹腔注射STZ以120mg/kg为最佳剂量。     

链脲佐菌素所致高血糖对大鼠缺血性脑损伤的影响

目的 研究链脲佐菌素所致糖尿病性高血糖（ＨＧ）对大鼠缺血性脑损伤的影响。方法 链脲佐菌素引起糖尿病４周的大鼠造成１０ｍｉｎ前脑缺血,观察缺血后脑组织的病理改变和癫痫发作情况。结果 在海马ＣＡ１区和下脚区,ＨＧ组与正常血糖（ＮＧ）组动物脑神经元损伤程度相似。然而,ＨＧ组动物有严重的顶叶皮质神经元坏死和“额外脑结构损伤”。ＨＧ组中４２．１％的动物脑缺血后出现癫痫发作,血浆葡萄糖浓度低于１２ｍｍｏｌ／Ｌ     

实验性慢性糖尿病大鼠局灶性脑缺血再灌注模型的制作

目的建立合适的实验性慢性糖尿病大鼠局灶性脑缺血再灌注模型,并比较分析影响模型制备成功的因素。方法140只体质量为180～220g的雄性Wister大鼠禁食12h后,于腹腔内一次性注射链脲霉素55mg/kg,普通饮食饲养42～47d,在饲养过程中每7d饮水中给予2次庆大霉素(6.4×104U/只)。选择体质量为240～310g、血糖水平13.5～25.6mmol/L的成模实验性慢性糖尿病大鼠制作脑缺血再灌注模型;另选择70只体质量为240～310g的同种雄性大鼠制作单纯脑缺血再灌注模型作为对照。采用Longa线栓法制作糖尿病脑缺血再灌注及单纯脑缺血再灌注大鼠模型,并用Longa神经功能评分标准,比较两组大鼠模型制备成功率,分析两组大鼠模型制备失败及死亡原因。结果(1)糖尿病模型制备:慢性糖尿病大鼠模型制备成功标准为血糖水平>13.5mmol/L,糖尿病组模型制备成功90只;淘汰50只,其中因衰竭而死亡19只,血糖水平未达标31只。在实验过程中,糖尿病组大鼠的血糖水平升高、体质量降低,与对照组相比差异有显著性意义(P<0.05或P<0.01)。(2)脑缺血再灌注模型制备:单纯脑缺血再灌注组大鼠神经功能评分低于糖尿病脑缺血再灌注组(P<0.05)。两组模型制备成功大鼠的大体标本与组织病理学变化相近,仅程度略有不同;糖尿病脑缺血再灌注组大鼠仅脑组织中线结构移位时     

上皮膜蛋白1在实验性糖尿病大鼠模型中额叶皮质血—脑屏障上的表达

目的测定不同时间点实验性糖尿病大鼠额叶皮质血—脑屏障(BBB)上皮膜蛋白1(EMP1)的表达。方法选成年健康雄性Sprague-Dawley大鼠随机分为链脲佐菌素(STZ)诱导糖尿病组(STZ组)和对照组(CON组),每组分为2w、4w、8w 3个亚组,采用免疫组织化学法检测EMP1的表达。结果STZ大鼠与CON大鼠比较,4w组中STZ大鼠上EMP1的表达显著增多(P0.01),2w组和8w组中差异无统计学意义;EMP1的表达在STZ大鼠各亚组之间及CON大鼠各亚组之间比较差异无统计学意义(P0.05)。结论 EMP1在实验性糖尿病大鼠额叶皮质BBB上的表达改变,在模型建立成功后4w时表达显著增加。     

偏侧帕金森病猴模型纹状体的质子磁共振波谱研究

目的观察偏侧帕金森病（PD）猴模型纹状体质子磁共振波谱（1H-MRS）的变化,探讨1H-MRS对PD的早期诊断价值。方法对4只恒河猴经右侧颈内动脉注射1-甲基4-苯基1、2、3、6-四氢吡啶（MPTP）制备偏侧PD猴模型前后的双侧纹状体进行1H-MRS检测,对比分析制模术前和术后猴双侧纹状体N-乙酰基天门冬氨酸（NAA）/肌酸复合物（Cr）和胆碱复合物（Cho）/Cr比值的变化。结果4只猴均成功制备成偏侧PD猴模型。偏侧PD猴模型MPTP毁损侧对侧纹状体NAA/Cr和Cho/Cr比值较制模术前无明显改变（P〉0.05）;但偏侧PD猴模型MPTP毁损侧纹状体NAA/Cr比值较制模术前和对侧明显降低（P〈0.05）,Cho/Cr比值较制模术前和对侧明显增高（P〈0.05）。结论H-MRS能够早期发现偏侧PD猴模型纹状体的代谢和生化改变,间接反映偏侧PD猴模型纹状体的神经细胞病理学改变,有助于PD的早期诊断。     

细胞间粘附分子-1在慢性糖尿病大鼠局部脑缺血再灌流损伤中的作用

目的探讨ICAM-1在糖尿病脑缺血再灌流损伤中的作用.方法采用线栓法脑缺血再灌注模型,比较糖尿病及正常大鼠缺血再灌注后脑内ICAM-1的表达、炎性细胞浸润及梗塞大小.结果糖尿病大鼠缺血再灌注组脑组织受到的缺血损害明显重于正常缺血再灌注大鼠组;糖尿病缺血大鼠脑内微血管内皮细胞ICAM-1的表达以及炎性细胞浸润程度明显高于正常缺血对照组(P＜0.05).结论糖尿病可加重局灶性脑缺血再灌流损伤并增强炎性反应的程度.超负荷血糖条件下ICAM-l可能是加重糖尿病脑缺血再灌流损伤的机制之一.     

Aβ1-42和thiorphan联合颅内给药建立恒河猴AD模型工作记忆无改变

目的观察Aβ_(1-42)和thiorphan联合颅内给药后恒河猴工作记忆是否发生改变。方法Wisconsin训练猴笼内用延迟反应的方法测试恒河猴的工作记忆,比较猴子在给药前后的10 s、30 s、60 s的正确应答率。结果给药前后恒河猴10 s、30 s、60 s的正确应答率无改变。结论Aβ_(1-42)和thiorphan联合颅内给药建立恒河猴AD模型,50 d内尚未观察到恒河猴工作记忆发生改变。     

侧脑室注射链脲酶素导致大鼠脑内能量代谢障碍和视空间记忆障碍

目的探讨脑内胰岛素／胰岛素受体信号系统功能紊乱与认知障碍的关系。方法采用2次双侧侧脑室注射链脲酶素（streptozotocin,STZ）方法建立大鼠模型。建模后21d检测大鼠线粒体呼吸链酶复合物和ATP酶活性;利用高效液相法检测大鼠海马ATP、ADP和AMP水平;Morris水迷宫检测视空间记忆障碍。结果STZ组大鼠脑内琥珀酸脱氢酶（succinate dehydrogenase,SDH）、细胞色素C氧化酶（cytochrome-oxydase,CCO）、Na^＋-K^＋ATPase、Ca^2＋-Mg^2＋-ATPase活性以及ATP和ADP水平与生理盐水对照组相比差异有统计学意义（P〈0．05）。Morris水迷宫实验中,STZ组大鼠平均潜伏期、平均路径长度、撤台后2min内经过平台次数与生理盐水对照组相比差异均有统计学意义（P〈0．05）。结论脑内胰岛素／胰岛素受体信号系统功能紊乱可导致与散发性老年性痴呆相似的脑内能量代谢障碍和视空间记忆障碍。     

恒河猴颞叶癫痫模型的建立

目的 应用立体定向方法单侧海马内注射海人酸,建立恒河猴颞叶癫痫模型,并评价其生物学特性.方法 通过立体定向手术,恒河猴右侧海马注射海人酸,观察恒河猴行为学、神经电生理、影像学、组织病理及超微结构改变.结果 海人酸注射后恒河猴出现典型的颞叶癫痫发作表现,脑电图表现为棘波、慢波、棘慢波、尖波发放.MRI、MRS可见海马硬化的表现,组织学标本显示颞角扩大、海马硬化,HE染色可见神经元缺失、胶质细胞增生、瘢痕萎缩,电镜显示神经元固缩、血脑屏障破坏、星形细胞肿胀、细胞器受损.结论 立体定向单侧注入海人酸后恒河猴癫痫发作明显,其行为学、神经电生理、影像学、神经病理改变符合颞叶内侧型癫痫表现,可作为癫痫模型.     

Primate models of separation-induced depression

Nonhuman primates have been shown to demonstrate behavioral and physiologic reactions to social separation that suggest symptoms of clinical depression. Although care must be taken in the use of animal models of psychopathology, it can be argued that in the case of certain affective disorders, including depression, nonhuman primate response to separation meets the criteria for validity. A variety of social, environmental, and genetic factors can influence the separation response in terms of intensity and specific types of symptomatology, and through the use of experimental manipulations, the relative importance of these and other variables in mediating depressive reactions have been studied. The effects of catecholamine depleting drugs (such as AMPT) as well as therapeutic agents on separation-induced depression in monkeys are being studied in an effort to determine underlying mechanisms of depression and particularly how neurochemical factors may interact synergistically with environmental and psychosocial factors in determining severity and nature of depressive reactions to separation.     

Axonal transport of the molecular forms of acetylcholinesterase in rats at the onset of diabetes induced by streptozotocin

During the development of streptozotocin-induced diabetic neuropathy in the rat, the axonal transport of 4 acetylcholinesterase molecular forms was studied by measuring their accumulation on both sides of transected sciatic nerves. Our results indicate that both the anterograde and retrograde axonal transport of all these forms remain normal between 2 and 5 weeks after the induction of diabetes by streptozotocin injection.     

Giant axonopathy in streptozotocin diabetes of rats

Summary The ultrastructure of peripheral sensory nerves was investigated in adult Wistar rats suffering from experimental diabetes mellitus 6 and 10 weeks after the injection of streptozotocin. Giant axons were seen in sections from the nerves of streptozotocintreated rats; some contained masses of neurofilaments, others were predominantly filled with ill-defined vesicles. At the swollen axons, the myelin sheath was thinned or absent. In other regions, large intramyelinic vacuoles were observed. A number of nerve fibers broke down completely and underwent Wallerian degeneration. This was accompanied by Schwann cell proliferation and formation of Büngner bands. Concomitantly with axonal degeneration, nerve regeneration started from intact internodes. The pathomorphology of streptozotocin diabetic neuropathy closely resembles that of some toxic distal axonopathies. This points to a common metabolic basis of giant axonopathies of different etiology.     

Spatial distribution of glucose hypometabolism induced by intracerebroventricular streptozotocin in monkeys

Intracerebroventricular injection of streptozotocin (icv-STZ) in rodents induces cellular and behavioral features mimicking Alzheimer's disease (AD). However, the effect of icv-STZ in terms of regional cerebral glucose metabolism has not yet been examined in vivo. Given that regionally specific hypometabolism of glucose is a consistent neuroimaging marker in early AD, we monitored 18F-deoxyglucose uptake using a high-resolution micro-PET after icv-STZ in non-human primates. Two cynomolgus monkeys (Macaca fascicularis) received STZ (2 mg/kg), and another two were given normal saline as controls, at the cerebellomedullary cistern (CM) three times (day 1, 7, and 14). FDG-PET, as well as MRI for structural evaluation, was performed immediately before, six weeks after, and 12 weeks after the first icv injection. In the STZ group, FDG uptake decreased significantly in comparison to the pre-injection baseline, at the precuneus, the posterior cingulate, and medial temporal cortices. Increase in sulcal markings suggesting brain atrophy was observed by MRI at six weeks post-injection. The structural changes normalized at 12 weeks, but the reduced FDG uptake persisted at the same loci. The cortical distribution of glucose hypometabolism was similar to that at early stages of AD patients. The findings demonstrate that the effect of icv-STZ is regionally specific, lending further support for the method as a model of AD pathogenesis.     

Expression and distribution of kinin B1 receptor in the rat brain and alterations induced by diabetes in the model of streptozotocin

A role for kinin B1 receptors was suggested in the spinal cord and peripheral organs of streptozotocin (STZ)-diabetic rats. The present study aims at determining whether B1 receptors are also induced and over-expressed in the brain of STZ-rats at 2, 7, and 21 days post-treatment. This was addressed by in situ hybridization using the [35S]-UTPalphaS-labeled riboprobe and by in vitro autoradiography with the radioligand [125I]-HPP-des-Arg10-Hoe 140. In control rats, B1 receptor mRNA was found widely distributed in many brain regions. Low mRNA levels were found in thalamus and hypothalamus (7-12 nCi/g) while high mRNA signals were detected in cortical regions and hippocampus (18-29 nCi/g). In diabetic rats, B1 receptor mRNA was markedly increased in hippocampus, temporal/parietal cortices and amygdala at 2 and 7 days (+88 to +150%). Low densities of B1 receptor binding sites were detected in all analyzed regions in control rats (0.18-0.37 fmol/mg tissue). In diabetic rats, B1 receptor binding sites were significantly increased in hippocampus, amygdala, temporal/parietal, and perhinal/piriform cortices (+ 55 to + 165 %) at 7 days only. Results highlight an early but transient and reversible up-regulation of B1 receptors in specific brain regions of STZ-diabetic rats. This may offer the advantage of reducing putative central side effects with B1 receptor antagonists if used for the treatment of diabetic complications in the periphery.     

Pre-training Catechin gavage prevents memory impairment induced by intracerebroventricular streptozotocin in rats

Objective:

To evaluate the effects of Catechin (CAT) on memory acquisition and retrieval in the animal model of sporadic alzheimer’s disease (sAD) induced by intracerebroventricular (icv) injection of streptozotocin (STZ) in passive avoidance memory test.

Methods:

Thirty adult rats were divided into 5 experimental groups (n=6). Animals were treated by icv saline/STZ (3 mg/kg) injection at day one and 3 after cannulation. The STZ+CAT group received 40 mg/kg CAT by daily gavages for 10 days, after icv STZ treatment and before training. The step-through latency (STL) and time spent in the dark compartment (TDC) were evaluated to examine the memory acquisition and retrieval. All tests were performed in Qom University of Medical Sciences, Qom, Iran, from April to December 2013.

Results:

The STZ treatment significantly decreased STL and increased the number of entries to the dark compartment on the training day. It also increased TDC, on day one and 7 after training. Pre-training gavage of CAT reversed the STL significantly (p=0.027). The CAT treatment also decreased the TDC in both early and late retrieval, in respect to STZ group.

Conclusion:

This data suggests that CAT as an antioxidant could improve both memory acquisition and retrieval in the animal model of sAD.According to reports in 2012, there are more than 35 million people living with dementia worldwide.1 Alzheimer’s disease (AD), which is characterized by amyloid (Aβ) plaque accumulation, is the most common forms of dementia, and results in memory loss and cognitive impairment.2 The pathological features of AD include Aβ peptide misfolding that form neurotic plaques on the neurons and intracellular neurofibrillary tangles composed of hyperphosphorylated tau protein.3 There are many reports indicating elevated oxidative stress in the brain of patients with mild cognitive impairment or AD.4 Oxidative stress may be the first feature in the brain of AD patients,5,6 which appears even before Aβ deposition.7,8 Transgenic mice bearing a mutant amyloid precursor protein (APP) similarly showed oxidative stress before Aβ deposition.9 The Aβ plaque formation is suggested to be an effort by the cell to protect itself against oxidative stress.10 The Aβ metabolism increases reactive oxygen species (ROS) and decreases adenosine triphosphate production in mitochondria.11 The secretion, oligomerization, and aggregation of Aβ is the result of its ROS sequestering activity and leads to destruction of cellular integrity.12 Other consequences of cellular oxidative damage include cell cycle aberration and tau hyperphosphorylation, leading to the formation of neurofibrillary tangles.13Polyphenolic flavonoids are neuroprotective against oxidative stress14 and possess potent radical scavenging15 and anti-inflammatory activities.16 Catechin (CAT) protects cultured mesencephalic neurons against 6-hydroxydopamine treatment,17 and also prevents primary hippocampal neurons from Aβ toxicity.18 Epicatechin gallate and epigallocatechin gallate was found to increase the activity of oxygen radical species-metabolizing enzymes, superoxide dismutase and catalase, in mouse striatum.19 The CAT is also capable of inhibiting lipid peroxidation induced by iron ascorbate in brain mitochondrial membranes.20 Evidence suggests that damages caused by Aβ can be undermined by antioxidants such as vitamin E21 or polyphenols.22 There are reports that CAT is more effective than vitamin E and C for the destruction of free radicals.15 So these antioxidants could be the major candidates for the prevention and treatment of AD. In this study, we evaluated the effects of CAT as a potent antioxidant on memory acquisition in the animal model of sporadic AD (sAD) induced by intracerebroventricular (icv) injection of streptozotocin (STZ) in passive avoidance memory test.     

Primate models of movement disorders of basal ganglia origin.

Movement disorders associated with basal ganglia dysfunction comprise a spectrum of abnormalities that range from the hypokinetic disorders (of which Parkinson's disease is the best-known example) at one extreme to the hyperkinetic disorders (exemplified by Huntington's disease and hemiballismus) at the other. Both extremes of this movement disorder spectrum can be accounted for by postulating specific disturbances within the basal ganglia-thalamocortical 'motor' circuit. In this paper, Mahlon DeLong describes the changes in neuronal activity in the motor circuit in animal models of hypo- and hyperkinetic disorders.     

The effect of streptozotocin diabetes on platelet function in rats.

Streptozotocin diabetes in rats induced alterations in platelet aggregation. These could be ascribed to both intrinsic and extrinsic factors. A pronounced increase in thrombin induced platelet aggregation and serotonin release, observed in citrated plasma as well as in platelet suspension indicated an intrinsic anomaly of platelet function. A diminution of ADP induced platelet aggregation in diabetic plasma which could be reversed by washing and a similar influence of diabetic plasma on normal platelets was clearly indicative of the influence of a plasma factor. These anomalies were observed to occur rapidly after the onset of diabetes, but before the development of retinal vascular changes. In view of the considerable speculation about the relationship between abnormal platelet function and the development of diabetic vascular disease, this model would appear to be uniquely suitable for further study of this problem.