冈田酸诱导大鼠海马神经元Tau 蛋白过度磷酸化

目的研究蛋白磷酸酯酶抑制剂冈田酸(OA)对海马神经元微管相关蛋白(Tau)磷酸化的影响,建立Tau过度磷酸化的大鼠模型。方法实验随机分为正常组、二甲基亚砜(DMSO)对照组、OA模型组。模型组又分为OA12h、24h、48h和2周组。OA模型组大鼠海马CA1区背侧定向注射1.5μl溶于10%DMSO的OA,DMSO对照组注射1.5μl10%DMSO溶液。通过Bielschowski染色、免疫组织化学染色、蛋白免疫印迹分别观察海马神经元形态的改变和磷酸化Tau的表达水平;检测蛋白磷酸酶2A(PP2A)的活性,了解其动态变化与Tau磷酸化的关系。结果OA模型各组与正常组和DMSO对照组比较,Bielschowski染色示海马神经元胞体和突起着色较深,欠均匀,部分神经元轴丘处浓染成斑块状,但各模型组均未见到老年斑和神经元纤维缠结样改变;免疫组织化学染色示模型组海马神经元Thr231和Ser199202磷酸化Tau蛋白表达增加,与DMSO对照组相比具有显著意义(P<0.05);蛋白免疫印迹提示OA可引起Tau蛋白Thr231、Ser396和Ser199/202位点发生磷酸化,且不同位点磷酸化的稳定性不同,注射OA48h后PP2A的活性明显降低,其变化与Tau蛋白Thr231和Ser396位点的磷酸化改变相一致。结论海马CA1区背侧单次注射OA可诱导建立神经元Tau蛋白过度磷酸化的大鼠模型。     

去铁敏对大鼠星型胶质细胞谷氨酸毒性的保护作用

目的:观察去铁敏对谷氨酸所致星型胶质细胞损伤的保护作用。方法:建立原代培养的星型胶质细胞谷氨酸毒性模型,采用免疫组化、Hoechst染色检测细胞形态及核固缩情况。CCK-8法检测细胞活力。生化法检测羟自由基、MDA变化。用显微荧光测量技术监测神经元内钙信号的动态变化。结果:随着谷氨酸浓度的增加细胞损伤也逐渐加重。与对照组相比,去铁敏处理后细胞对0.5,1.0,5.0mmol/L谷氨酸损伤形态保持良好;细胞核固缩率减少,分别为(10.44±5.03)%,(7.93±5.04)%和(11.01±3.73)%(P0.05);细胞活力下降减轻,分别为(94.72±2.20)%(P0.05),(82.49±1.94)%和(67.94±5.55)%(P0.01)。去铁敏处理后羟自由基水平下降,为10.17±1.79(P0.01)。MDA水平下降,为7.36±1.47(P0.01)。去铁敏预处理后钙离子增高的幅度及出现钙离子变化的细胞数较对照有明显减少。结论:去铁敏能减轻谷氨酸导致的星型胶质细胞损伤,能减少谷氨酸导致的星型胶质细胞内钙浓度的升高及自由基水平,这可能是去铁敏保护作用的机理之一。     

D-serine对阿尔茨海默病模型小鼠海马区tau蛋白过度磷酸化的影响

目的:探讨D-丝氨酸(D-serine)对阿尔茨海默病(AD)模型小鼠海马区tau蛋白过度磷酸化的影响。方法:42只SPF级昆明小鼠随机分为6组:Control组、Saline组、Aβ组、Aβ+D-serine组、Aβ+DAAO组、Aβ+BE组;每组7只动物。AD模型组小鼠双侧海马CA1区微量注射Aβ1-42造模,之后连续10 d分别腹腔注射生理盐水,D-serine(30 mg/kg),D-氨基酸氧化酶(DAAO)(30 mg/kg),苯甲酸钠(BE)(30 mg/kg)。采用免疫组织化学以及Western Blot方法检测各组小鼠海马区IL-1β、p-MAPT(S404)、p-GSK3β以及DCX表达的具体变化。结果:与Control组相比,Aβ组小鼠海马区IL-1β以及p-MAPT(S404)蛋白表达明显增多(P 0. 01),而p-GSK3β以及DCX蛋白表达明显减少(P 0. 01);而与Aβ组相比,Aβ+D-serine组IL-1β以及p-MAPT(S404)蛋白表达明显减少(P 0. 01); p-GSK3β以及DCX蛋白表达明显增多(P 0. 01)。结论:D-serine可以改善Aβ1-42诱导的AD模型小鼠海马区tau蛋白过度磷酸化以及神经损伤。     

App17肽对Tau蛋白超磷酸化表达的影响

目的 通过对Ｔａｕ蛋白磷酸化在脑内分布的观察,研究Ａｐｐ１７肽对糖尿病小鼠脑神经元Ｔａｕ蛋白磷酸化的影响。方法 用链脲佐菌素（ｓｔｒｅｐｔｏｚｏｔｉｏｎ,ＳＴＺ）诱发小鼠糖尿病模型,并皮下注射Ａｐｐ１７肽对糖尿病小鼠进行治疗,４周后取脑组织做ＡＴ－８、Ｔａｕ－１、蛋白磷酸酯酶（ＰＰ－２Ｂ）脱磷酸后的Ｔａｕ－１免疫组织化学染色。结果 糖尿病小鼠脑内ＡＴ－８阳性反应神经元广泛分布于压后颗粒皮层、海马、丘脑、下丘脑等倍位,胞浆深染,而正常小鼠及Ａｐｐ１７肽保护的糖尿病小鼠脑内阳性反应细胞仅在海马和压后颗粒皮层表达,阳性细胞数目少,染色淡;用Ｔａｕ－１单染正常小鼠脑及Ａｐｐ１７肽治疗的糖尿病小鼠脑的压后颗粒皮层及海马阳性反应神经元数目多,糖尿病小鼠只有用ＰＰ－２Ｂ脱磷酸后阳性反应神经元数目及染色程度才与正常组接近。结论     

胆固醇代谢障碍影响ob/ob小鼠室管膜下区神经发生

目的 检测胆固醇对ob/ob肥胖小鼠神经干细胞(NSCs)增殖和分化能力的影响,探讨肥胖引起中枢神经系统功能障碍的可能机制。方法 选取4月龄ob/ob和野生型(WT)小鼠各6只,运用细胞增殖抗原(Ki67)和双皮质素(DCX)免疫荧光染色检测ob/ob小鼠侧脑室室管膜下区(SVZ)神经发生水平;分离培养18只4月龄ob/ob和WT小鼠SVZ的NSCs,运用BrdU掺入实验和β-Ⅲ-微管蛋白(Tuj1)免疫荧光染色检测NSCs的自我更新和分化能力。运用基质辅助激光解飞行时间质谱(MALDI-MS)分别检测3只ob/ob和WT小鼠脑组织的脂质分布,并分析胆固醇(ST)含量和胆固醇合成相关基因的表达变化。体外培养15只WT新生鼠(P0)SVZ的NSCs,并通过电穿孔法转染胆固醇合成限速酶3-羟基-3-甲基-戊二酰辅酶A还原酶(Hmgcr)的小干扰RNA(siRNA),验证敲减效率,并通过BrdU掺入实验和Tuj1免疫荧光染色检测Hmgcr基因敲减对NSCs的影响。结果 与WT小鼠相比,ob/ob小鼠SVZ部位Ki67⁺和DCX⁺细胞数量均显著下降(...     

奥美沙坦对ob/ob小鼠血浆脂联素水平影响的研究

目的 观察ob/ob小鼠不同组间血浆脂联素浓度的变化以及奥美沙坦干预后脂联素浓度的变化.方法 以ob/ob小鼠为对象,分为三组:①ob/ob小鼠空白组;②ob/ob小鼠高脂组;③ob/ob小鼠奥美沙坦组,①喂以普通饲料;②③喂以高脂饮食,10周后,早期动脉粥样硬化成模后,给与①②组安慰剂及③组奥美沙坦分别进行干预,10...     

神经生长因子预处理阿尔茨海默病大鼠海马神经原磷酸化Tau蛋白的变化

背景：神经生长因子能够促进胆碱能神经元的分化,决定轴突的生长,并可参与损伤神经的再生和功能修复。 目的：进一步验证神经生长因子预处理对拟阿尔茨海默病模型大鼠脑内神经原纤维缠结和磷酸化Tau蛋白表达的影响。 方法：将3-5月龄雄性Wistar大鼠随机分为3组：模型组将冈田酸微量注射至拟大鼠海马CA1区建立拟阿尔茨海默病大鼠模型;预处理组于造模前将神经生长因子注射至侧脑室;对照组用同样方法注入等体积的二甲亚砜作为对照。通过Morris水迷宫观察上述大鼠的行为学变化,分别用改进的Bielschowsky染色观察海马CA1区神经原纤维缠结,用免疫组织化学和免疫印迹法观察海马区磷酸化Tau蛋白表达的变化。 结果与结论：拟阿尔茨海默病模型组大鼠出现认知、学习记忆能力减退;与对照组比较,模型组海马CA1区出现较多神经原纤维缠结, 而且磷酸化的Tau蛋白表达增多;神经生长因子预处理组大鼠的上述症状明显改善。提示神经生长因子预处理可以显著改善拟阿尔茨海默病模型大鼠的学习记忆能力,抑制神经原纤维缠结的形成,减少磷酸化Tau蛋白的表达。     

小热休克蛋白家族和自噬相关蛋白 在自发性2型糖尿病db/db小鼠海马组织中的表达

目的观察自发性2型糖尿病db/db小鼠海马组织中小热休克蛋白家族(sHSPs)及自噬相关蛋白表达情况。方法正常db/m小鼠作为对照组,糖尿病db/db小鼠作为模型组,各10只。观察其体质量,空腹血糖(FBG);real-time PCR检测海马组织中小热休克蛋白家族、自噬相关基因mRNA的表达;Western blot检测HSPB8、BAG3、LC3、P62蛋白表达。结果 1)db/db小鼠体质量、空腹血糖均明显高于db/m小鼠(P0.01)。2)小热休克蛋白1-10(heat shock protein family B [small] member 1-10,HSPB 1-10)基因mRNA在小鼠海马组织中均有表达;其中HSPB1、HSPB3、HSPB5、HSPB6和HSPB8 db/db组明显低于db/m组(P0.05);HSPB2、HSPB9和HSPB10 db/db组高于db/m组(P0.05);而在db/db小鼠中LC3表达高于db/m组(P0.01),而P62反之(P0.01)。3)较db/m组,db/db组HSPB8、BAG3、LC3-Ⅱ蛋白表达均增高(P0.01),相反P62蛋白表达减低(P0.05)。结论 1)10种sHSPs均在小鼠海马组织中表达,但表达特点有所不同。2)8周龄糖尿病小鼠海马组织中存在HSPB8蛋白表达增强,且自噬激活。     

2型糖尿病模型db/db小鼠海马NOS阳性神经元变化

目的　观察人类 2型糖尿病模型———C5 7BL/KsJdb/db(db/db)小鼠海马NOS阳性神经元变化。方法　糖尿病组 :6周龄C5 7BL/KsJ(db +db +)小鼠 5只 ,尾静脉空腹血糖高于 11.1mmol/L且肥胖。对照组 :非糖尿病小鼠C5 7BL/KsJ(?+) 5只 ,尾静脉空腹血糖低于 6 .0mmol/L体重正常 ,于 30周龄 (成模第 6月末 )时 ,灌注固定取脑 ,以NADPH d组化法显示海马NOS阳性神经元。结果　与正常对照组相比 ,糖尿病组小鼠海马齿状回NOS阳性神经元密度显著减少 (P <0 0 1)。结论　糖尿病时NOS阳性神经元数量减少 ,NO的合成降低表明NO可能参与糖尿病中枢神经系统功能障碍     

去势雌性大鼠海马区Tau蛋白Alzheimer样磷酸化的变化

目的:探讨去势雌性大鼠海马区Tau蛋白Alzheimer样磷酸化的变化。方法:建立大鼠双侧卵巢切除(OVX)模型, 分别于术后1周、2周、3周、4周和8周取大鼠海马组织,Western blot检测Tau蛋白的磷酸化程度。结果:OVX组去势后4周和8周在海马区的PHF-1位点异常磷酸化Tau蛋白显著高于假手术组(P<0.01),而相同时间点和相同区域的Tau-1位点非磷酸化Tau蛋白的水平显著低于假手术组(P<0.01)。结论:卵巢切除可导致雌性大鼠海马区Tau蛋白Alzheimer样过度磷酸化。     

Up-regulation of the endocannabinoid system in the uterus of leptin knockout (ob/ob) mice and implications for fertility

The levels of the endocannabinoids anandamide and 2-arachidonoylglycerol (2-AG) are under the negative control of leptin in the rodent hypothalamus. As leptin and endocannabinoids play opposite roles in the control of reproduction, we have investigated whether the impaired fertility typical of leptin-defective ob/ob mice is due, in part, to enhanced uterine endocannabinoid levels. We found that levels of both anandamide and 2-AG in the uterus of ob/ob mice are significantly elevated with respect to wild-type littermates, due to reduced hydrolase activity in the case of anandamide, and to reduced monoacylglycerol lipase and enhanced diacylglycerol lipase activity in the case of 2-AG. Furthermore, the process mediating endocannabinoid cellular uptake was also impaired in ob/ob mice, whereas the levels of cannabinoid and anandamide receptors were not modified. Although ineffective in wild-type mice, treatment of ob/ob mice with leptin re-established endocannabinoid levels and enzyme activities back to the values observed in wild-type littermates. Finally, treatment of ob/ob females with the CB1 receptor antagonist SR141716A did not improve their fertility, and inhibition of endocannabinoid inactivation with the endocannabinoid uptake inhibitor OMDM-1 in wild-type females did not result in impaired fertility.     

Temperature preference of genetically obese (ob/ob) mice

Genetically obese (ob/ob) and lean mice selected their preferred ambient temperature in a thermal gradient. Preferred ambient temperature was defined as that ambient temperature which the mice selected for sleep during daylight hours. Lean mice selected a temperature of 31.2 degrees C which resulted in a body temperature (36.7 degrees C) not greatly different from the pretest body temperature of 36.4 degrees C. Obese mice selected 29.4 degrees C which resulted in a body temperature of 36.8 degrees C, 1.8 degrees C above the pretest body temperature of 35.0 degrees C. These data indicate that obese mice select an ambient temperature that results in a body temperature no different from that of lean mice. The selection by obese animals of an ambient temperature significantly lower than that of lean mice but which results in the same body temperature may reflect an effect of adiposity on heat loss. There is no evidence of a diminished thermoregulatory set-point in obese mice.     

Amelioration of non-alcoholic steatohepatitis and glucose intolerance in ob/ob mice by oral immune regulation towards liver-extracted proteins is associated with elevated intrahepatic NKT lymphocytes and serum IL-10 levels

Non-alcoholic steatohepatitis (NASH) is a common cause of cryptogenic cirrhosis in the Western world. In an animal model of NASH, leptin-deficient ob/ob mice present with alterations in number and function of hepatic NKT and peripheral CD4 lymphocytes. Oral immune regulation is a method to alter the immune response towards orally administered antigens. To determine the effect of oral immune regulation towards liver-extracted proteins on the metabolic disorders in ob/ob mice, ob/ob mice and their lean littermates were orally administered liver extracts from wild-type or ob/ob mice or bovine serum albumin for 1 month. The effect of treatment on hepatic fat content was measured by magnetic resonance imaging (MRI) and using a histological steatohepatitis grading scale. Glucose tolerance was measured by an oral glucose tolerance test (GTT). T lymphocyte subpopulations were assessed by flow cytometry analysis. Induction of immune regulation by oral presentation of liver-extracted proteins resulted in a significant 18% reduction of the hepatic fat content in ob/ob mice fed with either wild-type or ob/ob liver extracts for 1 month. The MRI signal intensity index in treated mice decreased to 0.48 and 0.51, respectively, compared with 0.62 in BSA-fed controls (p = 0.037 and p = 0.019, respectively), while the histological steatohepatitis score decreased in both treated groups to 2.0, compared with 2.4 in BSA-fed controls (p = 0.05). A significant improvement in GTT was noted in treated ob/ob mice. These changes were accompanied by a marked increase in the intrahepatic NKT lymphocyte population in mice fed with proteins extracted from both wild-type and ob/ob mice (46.96% and 56.72%, respectively, compared with 26.21% in BSA-fed controls; p < 0.05) and a significant elevation in serum IL-10 levels. Oral immune regulation towards liver extracted proteins in leptin-deficient mice resulted in a marked reduction in hepatic fat content and improved glucose tolerance. This effect was associated with a significant increase in the intrahepatic NKT lymphocyte population and serum IL-10 levels, suggesting a Th1 to Th2 immune shift. Immune regulation towards disease-associated antigens holds promise as a new mode of therapy for NASH.     

Upregulated Expression of AQP 7 in the Skeletal Muscles of Obese ob/ob Mice

Aquaporin (AQP) is suggested to be regulated by leptin through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway. AQP7 and AQP9 are membrane proteins with water and glycerol channels, the latter of which is essential for triglyceride synthesis. We conjectured that the expression of AQP7 and AQP9 would be altered in the skeletal myofibers in obese leptin deficient ob/ob mice as compared with that of wild mice. RNA and protein levels were studied in the quadriceps femoris muscles of ob/ob and wild mice. Real time quantitative RT-PCR analysis showed that mouse AQP7 mRNA levels in skeletal muscles were significantly higher in ob/ob mice than in wild mice (P<0.01), whereas mouse AQP9 mRNA level was not different between the two groups (P>0.05). Histologically the type 1 myofibers of ob/ob mice contained numerous lipid droplets in oil red O stain samples. Immunohistochemical staining of ob/ob mouse muscles revealed enhanced expression of AQP7 at myofiber surface membranes, while AQP9 expression appeared to be similar to that of wild mice. The findings suggest that the upregulated expression of AQP7 in ob/ob mouse muscles facilitates the secretion of glycerol from myocytes.     

肥胖小鼠脂肪组织中炎症因子的表达

目的 探讨肥胖对小鼠脂肪中炎症因子分泌的影响及其作用的分子机制。方法 随机选取20只Lepob/ob肥胖小鼠作为研究对象,同窝野生型C57BL/6 J小鼠作为对照组。测定小鼠体重、脂肪重量、血糖、葡萄糖耐量和胰岛素耐量;HE染色观察白色和褐色脂肪细胞的状态,并对脂肪细胞直径进行统计学分析;Western blotting检测诱导型一氧化氮合酶(iNOS)、核因子κB（NF-κB）、蛋白激酶B（Akt）和p-Akt的蛋白表达;Real-time PCR分析白色和褐色脂肪中CC-趋化因子配体2(CCL2)、CD44、集落刺激因子2(CSF2)、胶质纤维酸性蛋白（GFAP）、Iba1、白细胞介素(IL)-1α、IL-6、IL-7、JUN和S100β mRNA的表达。结果 与对照组相比,Lepob/ob 小鼠的体重随年龄的增长而显著增加（P<0.001）,白色脂肪重量、皮下脂肪重量及血糖显著升高（P<0.01,P<0.01,P<0.01）,葡萄糖耐量较低（P<0.001）并产生胰岛素抵抗（P<0.001）;脂肪细胞直径显著增大,且各个脂肪组织均有巨噬细胞浸润灶出现;脂肪细胞内Janus蛋白酪氨酸激酶2(JAK2)、p-JAK2、iNOS、NF-κB、Akt和p-Akt蛋白表达均显著升高（P<0.05）;CCL2、CD44、IL-1α、IL-6、IL-7、JUN和S100β mRNA表达均显著升高。 结论 肥胖诱导小鼠脂肪组织中炎症因子显著表达,促使细胞分泌传导紊乱,导致炎症级联发生。     

Behavioral response of the genetically obese (ob/ob) mouse to heat stress: effects of naloxone and prior exposure to immobilization stress

Genetically obese (ob/ob) mice, which possess abnormally elevated levels of pituitary β-endorphin and adrenocorticotropin exhibited less grooming, rearing and jumping during a five min exposure to different levels of heat stress compared to their lean littermate controls (ob/?). Naloxone had a diametrically opposite effect on rearing in these animals, particularly when exposed to low heat stress; it enhanced rearing in ob/ob mice and suppressed the rearing response in ob/? mice. Naloxone enhanced jumping in both the ob/ob mice and the ob/? mice. This effect was slightly, although not significantly, stronger in the obese mice. Finally, exposure to 10 min of immobilization stress before testing at 46°C, enhanced grooming and suppressed jumping in ob/ob and ob/? mice. Naloxone pretreatment reversed the effect of immobilization stress in ob/ob mice but not in their lean littermate controls. The data is discussed in terms of the differential involvement of pituitary endorphins in the behavioral response of ob/ob and ob/? mice to stress.     

Paradoxical Effects of Partial Leptin Deficiency on Bone in Growing Female Mice

Morbidly obese, leptin‐deficient ob/ob mice display low bone mass, mild osteoclast‐rich osteopetrosis, and increased bone marrow adiposity. While partial leptin deficiency results in increased weight, the skeletal manifestations of partial leptin deficiency are less well defined. We therefore analyzed femora and lumbar vertebrae in growing (7‐week‐old) female C57BL/6 wildtype (WT) mice, partial leptin‐deficient ob/+ mice, and leptin‐deficient ob/ob mice. The bones were evaluated by dual energy absorptiometry, microcomputed tomography and histomorphometry. As expected, ob/+ mice were heavier, had more white adipose tissue, and lower serum leptin than WT mice, but were lighter and had less white adipose tissue than ob/ob mice. With a few exceptions, cancellous bone architecture, cell (osteoblast, osteoclast, and adipocyte), and dynamic measurements did not differ between WT and ob/+ mice. In contrast, compared to WT and ob/+ mice, ob/ob mice had lower cancellous bone volume fraction, and higher bone marrow adiposity in the femur metaphysis, and higher cancellous bone volume fraction in lumbar vertebra. Paradoxically, ob/+ mice had greater femoral bone volume than either WT or ob/ob mice. There was a positive correlation between body weight and femur volume in all three genotypes. However, the positive effect of weight on bone occurred with lower body weight in leptin‐producing mice. The paradoxical differences in bone size among WT, ob/+, and ob/ob mice may be explained if leptin, in addition to stimulating bone growth and cancellous bone turnover, acts to lower the set‐point at which increased body weight leads to a commensurate increase in bone size. Anat Rec, 298:2018–2029, 2015. © 2015 Wiley Periodicals, Inc.     

凋亡细胞在db/db自发性糖尿病小鼠颌下腺的分布

目的:观察凋亡细胞在db/db糖尿病小鼠颌下腺中的分布。方法:选取3、4、6、8、10月龄db/db糖尿病小鼠及相应月龄的dh/m~(?)小鼠颌下腺,应用TUNEL标记方法染色后进行图像分析.统计凋亡细胞在颌下腺组织中分布的细胞阳性率。结果:随着糖尿病的发展,颌下腺组织出现腺体萎缩及颗粒曲管数目减少,实质细胞排列不整齐,呈簇状堆集,纤维及血管增多。凋亡细胞在对照组及糖尿病组颌下腺中均有分布,糖尿病组凋亡细胞阳性率高于对照组。糖尿病组与对照组凋亡细胞阳性率随月龄增大均呈增加趋势。结论:db/db糖尿病可导致颌下腺组织萎缩及实质细胞形态学改变;凋亡细胞阳性率在糖尿病组随疾病发展而增加显著。这与糖尿病腺体萎缩和功能受损相一致。