老年小鼠海马CA1区轴棘突触微细结构的定量分析

目的观察老年小鼠海马CA1区轴棘突触相关结构的改变,为衰老引起的学习记忆减退提供神经解剖学依据。方法利用Golgi染色、超薄连续切片及NIH图像分析系统测量海马CA1区锥体细胞树突棘的密度、树突棘头及突触后致密斑的大小。结果海马CA1第2、3级顶树突的树突棘密度在3月龄组与22月龄组分别为(1.056±0.049)/μm和(0.868±0.038)/μm;穿孔型突触的比率3月龄与22月龄组分别为12.7%和19%。结论老年小鼠海马CA1区锥体细胞树突棘的减少、穿孔型突触比率的增加可能是衰老引起学习记忆减退的形态学基础。     

快速老化小鼠P8海马神经元突触结构与功能可塑性

目的从海马神经元突触结构与功能可塑性角度探讨阿尔茨海默病(AD)认知功能缺损的可能原因。方法以10月龄快速老化小鼠(SAMP)8为AD模型,同月龄抗快速老化小鼠(SAMR)1为正常对照,采用Morris水迷宫实验评价动物学习记忆能力,透射电镜观察海马CA1区神经元突触超微结构,在体长时程增强(LTP)记录观察海马前穿通纤维-齿状回(PP-DG)通路神经元突触传递效能。结果与SAMR1比较,SAMP8逃避潜伏期延长(P=0.000),穿越有效区次数减少(P=0.046);海马CA1区神经元突触后致密带变薄(P=0.000),突触间隙增宽(P=0.024),突触界面曲率下降(P=0.000);海马PP-DG通路LTP诱发率(P=0.362)、群峰电位(P=0.900)及潜伏期(P=0.394)差异无统计学意义。结论海马CA1区突触超微结构受损可能是导致SAMP8学习记忆能力下降的原因,CA1区与DG区在AD病理上可能扮演不同角色。     

SAMP8海马CA1区突触素表达及针刺的干预作用

目的观察早老性痴呆模型8月龄快速老化小鼠(SAMP8)海马突触素的表达变化及针刺对其表达的影响。方法将30只SAMP8分成P8组和针刺组,以同月龄抗老化小鼠SAMR1为R1组,采用HE染色法观察各组小鼠海马CA1区锥体细胞形态的改变,以real-time PCR和免疫组织化学法观察各组小鼠海马CA1区突触素基因和蛋白的表达情况。结果 SAMP8海马CA1区的锥体细胞排列、形态及结构都明显受到损伤,针刺对其有改善作用。进一步研究发现P8组海马突触素基因和蛋白的表达量与R1组相比明显减少(P0.05),而针刺能增加其表达量(P0.05)。结论 SAMP8海马突触存在分子和形态学的损伤,针刺可通过增加突触素的表达发挥治疗阿尔茨海默病(AD)的作用。     

mGluR1蛋白诱导海马组织自噬对脑血管痉挛小鼠学习记忆能力的影响

目的探讨小鼠脑血管痉挛(CVS)后代谢型谷氨酸受体1(mGluR1)对神经细胞自噬的影响。方法采用非开颅血管内穿线法制备小鼠CVS模型,随机分为假手术组、模型组、mGluR1拮抗剂LY367385组,于术后10 min侧脑室注射生理盐水或LY367385(500 nmol)5μl,采用Y型电迷宫检测小鼠自主活动及学习记忆能力。分别于SAH术后6、24、48 h 3个时相点取脑组织标本,HE染色观察右侧海马CA1区组织学变化,免疫印迹法检测mGluR1、Beclin-1蛋白表达。结果与对照组比较,模型组小鼠神经功能评分显著降低,随痉挛时间延长,各组小鼠mGluR1、Beclin-1蛋白均有不同程度增强(P<0.05)。与模型组比较,拮抗剂组mGluR1、Beclin-1蛋白表达均有不同程度下调(P<0.05),并且神经功能评分得到改善。结论脑血管痉挛后mGluR1表达增强可通过激活Beclin-1途径诱导小鼠海马区神经细胞自噬。     

老年小鼠突触可塑性和记忆功能变化与nNOS表达的关系

目的 对老年小鼠突触可塑性和记忆能力变化与海马nNOS表达变化之间的关系进行探讨.方法 2月龄(青年)和16月龄(老年)昆明小鼠分别用Y型迷宫测试自发交替和活动能力,离体脑片细胞外观测海马长时程增强(LTP)的变化,免疫组化检测海马nNOS阳性细胞表达的变化.结果 老年小鼠的自发交替的百分率和活动能力较青年小鼠明显下降(P＜0.01),离体海马脑片LTP诱发成功率和群峰电位振幅增大率明显下降(P＜0.01),海马CA1区、齿状回的nNOS阳性细胞的染色强度减弱(P＜0.01).结论 小鼠在衰老过程中会伴有突触可塑性和记忆功能降低,其病理机制和nNOS神经元丧失有关.     

参苓不忘颗粒对去卵巢大鼠海马组织形态学和突触密度的影响

目的 研究参苓不忘颗粒对去卵巢大鼠学习记忆能力、海马CA1区组织形态学和突触密度的影响.方法 用切除两侧卵巢的方法制备大鼠的模型.将Wistar大鼠随机分为5组假手术(Sham)组、去卵巢(OVX)组、已烯雌酚对照(DES)组、参苓不忘颗粒高剂量组(3.6 mg·kg-1·d-1)和低剂量组(1.8 mg·kg-1·d-1).应用Morris水迷宫检测大鼠学习记忆能力;以透射电镜观察海马CA1区神经元的超微结构,统计突触密度的变化. 结果中药参苓不忘颗粒可明显改善去卵巢模型大鼠低下的学习记忆能力,可明显改善模型大鼠脑组织海马CA1区神经元的退行性变化,显著提高海马CA1区的突触密度.结论 参苓不忘颗粒能提高模型大鼠低下的记忆能力,其可能与改善海马CA1区神经元的退行性变化,提高突触密度有关.     

APP5肽类似物P165对糖尿病小鼠海马突触蛋白的影响

目的探讨β-淀粉样前体蛋白（APP）5肽类似物P165对糖尿病小鼠海马神经元α-突触核蛋白（α-Syn）、Shank1和突触后致密物质95（PSD-95）的影响。方法链脲佐菌素腹腔注射诱发DM小鼠模型，P165灌胃治疗。5周后，行灌注固定，海马CA1区α-Syn、Shank1和PSD-95免疫组织化学染色。结果与对照组相比，糖尿病（DM）组α-Syn阳性细胞增多（P〈0.01），胞浆突起深染，Shank1和PSD-95阳性细胞减少，染色浅（P〈0.01）；与DM组相比，P165治疗组α-Syn阳性细胞减少（P〈0.05），胞浆突起染色变浅；Shank1和PSD-95阳性细胞增多（P〈0.05），胞浆突起深染。结论糖尿病小鼠海马神经元存在突触蛋白表达的异常，P165可改善DM小鼠海马神经元突触蛋白的表达。     

D-半乳糖对大鼠海马氨基酸含量及海马CA1区突触结构参数的影响

目的　观察经 D-半乳糖长期处理的大鼠海马氨基酸含量及海马 CA1区突触结构参数的改变。方法　应用反相高效液相法对大鼠海马氨基酸含量进行分析 ,应用透射电镜结合图像分析对突触结构参数进行观察。结果　 (1 ) D-半乳糖可导致模型大鼠天冬氨酸、牛磺酸、γ-氨基丁酸含量降低 ,谷氨酸含量升高 (P<0 .0 5) ;(2 )在突触结构参数中 ,经 D-半乳糖处理的大鼠突触间隙明显增宽、突触后致密物厚度变薄、突触活性区长度缩短 (P<0 .0 5) ,突触界面曲率三组间无差异。结论　 D-半乳糖可改变大鼠海马氨基酸含量 ,并可显著影响大鼠海马突触结构参数     

亚甲蓝对APP/PS1小鼠海马CA1区树突棘密度的保护作用

目的探讨亚甲蓝(MB)对APP/PS1转基因小鼠海马CA1区树突棘密度改变及学习记忆能力改善的影响。方法 APP/PS1小鼠及相同品系的3月龄野生小鼠,随机分为3组,每组10只:正常对照组,为野生小鼠。模型组,为APP/PS1小鼠;治疗组,3月龄的APP/PS1小鼠口服亚甲蓝25 mg·kg-1·d-1;连续用药4个月。待3组小鼠均为7月龄时,跳台实验测试3组小鼠的学习记忆能力;高尔基染色观察各组海马CA1区树突棘密度的变化。结果亚甲蓝治疗组小鼠跳台试验错误次数减少,小鼠跳台试验的潜伏期明显延长(P<0.01);治疗组与模型组相比海马CA1区树突棘密度明显增加(P<0.01),治疗组与对照组无统计学差异(P>0.05)。结论亚甲蓝可能是通过增加海马CA1区树突棘密度来改善APP/PS1小鼠的学习记忆能力。     

丁苯酞对急性酒精中毒小鼠海马γ网络振荡的保护作用

目的研究丁苯酞(NBP)对急性酒精中毒小鼠学习记忆能力、脑内海马CA3区γ网络振荡的保护作用。方法应用场电位记录30只C57BL/6小鼠(3月龄、6月龄、12月龄各10只)急性酒精中毒前后、NBP作用前后的海马γ网络振荡的幅值及频率变化。结果 100 mmol/L无水乙醇使不同月龄(3月龄,6月龄,12月龄)组小鼠海马脑片海马γ网络振荡的能谱分别下降(39. 26±4. 97)%、(53. 85±6. 65)%、(28. 30±13. 68)%,差异显著(P<0. 001)。100μmol/L NBP使不同月龄(3月龄,6月龄,12月龄)组急性酒精中毒小鼠海马脑片海马γ网络振荡的能谱分别上升(57. 37±8. 94)%、(107. 82±18. 67)%、(47. 82±7. 26)%,差异有统计学意义(P<0. 001)。结论 NBP能够有效减轻急性酒精中毒对小鼠海马CA3区神经元造成的损伤,缓解急性酒精中毒对小鼠学习记忆能力的损害,其作用机制可能与NBP对神经元突触传递及线粒体的保护作用有关。     

H5N1禽流感病毒感染孕鼠的研究

目的用H5N1禽流感病毒感染昆明孕鼠,检测病毒在感染孕鼠各组织脏器中的复制及分布情况,并证明病毒能否通过孕鼠的胎盘垂直传染给胎鼠。方法用虎源H5N1亚型禽流感病毒滴鼻感染妊娠10-12 d的昆明孕鼠,观察孕鼠感染后的临床症状。接种病毒后第3、4、5、6和7 d分别处死3只孕鼠,取孕鼠的肺、脑、脾、肾、子宫、胎盘及胎鼠,利用RT-PCR、Real-time PCR和病毒分离方法检测各组织中的病毒核酸和病毒滴度,并进行病理组织学与免疫组织化学检测。结果昆明孕鼠接种病毒后第3 d,即可在肺、脑、脾、肾、子宫及胎盘组织中检测出H5N1禽流感病毒核酸,并从子宫、胎盘分离出H5N1禽流感病毒;感染后第6 d,从胎鼠体内检测到病毒核酸并分离出H5N1禽流感病毒。结论H5N1亚型禽流感病毒可以感染孕鼠,在孕鼠子宫和胎盘复制,感染后期可通过胎盘屏障传给胎鼠。     

Elevated anxiety and antidepressant-like responses in serotonin 5-HT1A receptor mutant mice

The brain serotonin (5-hydroxytryptamine; 5-HT) system is a powerful modulator of emotional processes and a target of medications used in the treatment of psychiatric disorders. To evaluate the contribution of serotonin 5-HT_1A receptors to the regulation of these processes, we have used gene-targeting technology to generate 5-HT_1A receptor-mutant mice. These animals lack functional 5-HT_1A receptors as indicated by receptor autoradiography and by resistance to the hypothermic effects of the 5-HT_1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Homozygous mutants display a consistent pattern of responses indicative of elevated anxiety levels in open-field, elevated-zero maze, and novel-object assays. Moreover, they exhibit antidepressant-like responses in a tail-suspension assay. These results indicate that the targeted disruption of the 5-HT_1A receptor gene leads to heritable perturbations in the serotonergic regulation of emotional state. 5-HT_1A receptor-null mutant mice have potential as a model for investigating mechanisms through which serotonergic systems modulate affective state and mediate the actions of psychiatric drugs.     

Oxygen free radical involvement in acute lung injury induced by H5N1 virus in mice

Background

Acute lung injury is an important cause of death in humans infected with H5N1. It has been found that oxygen free radicals (OFRs) are elevated in lung tissue during influenza virus infections. In this study, we used a mouse model to explore the role of OFRs in acute lung injury caused by H5N1 viral infection.

Methods

Four‐ to six‐week‐old male specific pathogen‐free BALB/c mice were inoculated intranasally with 10⁵ 50% tissue culture infective doses (TCID₅₀) of highly pathogenic A/Chicken/Hebei/108/2002 (H5N1) viruses and were then given 1000 IU of lauric acid modified superoxide dismutase (LA‐SOD) by intraperitoneal injection, starting 2 days post‐infection and continuing for 6 days.

Results

The extent of lung injury and the concentration of OFRs were higher, and the SOD activity was lower in H5N1 virus‐infected mice than that in uninfected control mice on days 3, 6, and 7 post‐inoculation. Weak amelioration of clinical signs, a minor decrease in the total mortality and the extent of lung injury, and the lower OFRs concentration were seen in the LA‐SOD treatment group, but a reduction in lung virus titers was not observed in the LA‐SOD treatment at all time points.

Conclusions

The LA‐SOD treatment has a mild inhibitory effect on H5N1 influenza virus infection in mice. OFRs, therefore, might play an important role in the pathogenesis of acute lung injury induced by H5N1 virus.     

Protective effect of C5a receptor 1 antagonist on ascending urinary tract infection in mice

正Objective To investigate the protective effect of complement 5a receptor 1 (C5aR1) antagonist on ascending urinary tract infection in mice.Methods (1) Female C57BL/6 mice were randomly divided into experimental and control groups:38 mice in each group, and inoculated withE. coliby urethral catheterization to set     

The therapeutic effects of sodium cromoglycate against influenza A virus H5N1 in mice

Objectives

To identify the protective role of sodium cromoglycate in mice during influenza virus infection.

Design

H5N1 virus‐infected mice were treated with the mast cell stabilizer sodium cromoglycate (SCG) to investigate its therapeutic effect.

Sample

The nose, trachea and lungs from mice were collected.

Main outcome measures

Virus replication and host responses were determined by plaque assay, quantitative PCR, immunohistochemistry, and histology.

Results

SCG‐treated mice survived better than did PBS‐treated mice after H5N1 virus infection. Mild pathological changes with fewer inflammatory cell infiltration and fewer virus antigens were observed in the nose, trachea, and lungs of SCG‐treated mice on days 3 and 5 post‐infection. However, no significant changes in viral load in the lungs were detected between SCG‐ and PBS‐treated mice. Furthermore, significantly decreased expression of interleukin‐6, tumor necrosis factor‐a, Toll‐like receptor 3, and TIR‐domain‐containing adapter‐inducing interferon‐b was detected in the lungs of SCG‐treated mice, and no higher expression of interferon‐c was detected.

Conclusion

These results suggest that SCG has therapeutic roles in H5N1 virus‐infected mice by alleviating the inflammatory response rather than inhibition of viral replication in the lungs.     

Haploinsufficiency of Snf5 (integrase interactor 1) predisposes to malignant rhabdoid tumors in mice

Malignant rhabdoid tumor (MRT) is an aggressive, highly lethal cancer of young children. Tumors occur in various locations, including kidney, brain, and soft tissues. Despite intensive therapy, 80% of affected children die, often within 1 year of diagnosis. The majority of MRT samples and cell lines have sustained biallelic inactivating mutations of the hSNF5 (integrase interactor 1) gene, suggesting that hSNF5 may act as a tumor suppressor. We sought to examine the role of Snf5 in development and cancer in a murine model. Here we report that Snf5 is widely expressed during embryogenesis with focal areas of high-level expression in the mandibular portion of the first branchial arch and central nervous system. Homozygous knockout of Snf5 results in embryonic lethality by embryonic day 7, whereas heterozygous mice are born at the expected frequency and appear normal. However, beginning as early as 5 weeks of age, heterozygous mice develop tumors consistent with MRT. The majority of tumors arise in soft tissues derived from the first branchial arch. Our findings constitute persuasive genetic evidence that Snf5, a core member of the Swi/Snf chromatin-remodeling complex, functions as a tumor suppressor gene, and, moreover, Snf5 heterozygotes provide a murine model of this lethal pediatric cancer.     

Nanobodies with in vitro neutralizing activity protect mice against H5N1 influenza virus infection

Influenza A virus infections impose a recurrent and global disease burden. Current antivirals against influenza are not always effective. We assessed the protective potential of monovalent and bivalent Nanobodies (Ablynx) against challenge with this virus. These Nanobodies were derived from llamas and target H5N1 hemagglutinin. Intranasal administration of Nanobodies effectively controlled homologous influenza A virus replication. Administration of Nanobodies before challenge strongly reduced H5N1 virus replication in the lungs and protected mice from morbidity and mortality after a lethal challenge with H5N1 virus. The bivalent Nanobody was at least 60-fold more effective than the monovalent Nanobody in controlling virus replication. In addition, Nanobody therapy after challenge strongly reduced viral replication and significantly delayed time to death. Epitope mapping revealed that the VHH Nanobody binds to antigenic site B in H5 hemagglutinin. Because Nanobodies are small, stable, and simple to produce, they are a promising, novel therapeutic agent against influenza.