外源性硫化氢对海洛因依赖大鼠海马长时程增强的影响

目的:观察外源性H2S供体NaHS对海洛因依赖大鼠学习记忆能力及海马LTP的影响。方法:SD大鼠随机分成3组:正常对照组、heroin组、heroin+NaHS组。先通过跳台实验检测大鼠学习记忆能力,然后记录高频刺激(HFS)前后在体海马CA1区群体峰电位(PS)变化,诱导长时程增强(LTP)的产生,最后通过Nissl染色观察海马神经元的损伤情况。结果:与对照组比较,heroin组和heroin+NaHS组学习记忆成绩均降低(P<0.05),PS幅值变化率减小(P<0.01),且形态学观察可见海马神经元损伤;与heroin组比较,heroin+NaHS组学习记忆成绩提高(P<0.05),PS幅值变化率增大(P<0.01),海马神经元损伤较轻。结论:(1)海洛因依赖导致大鼠海马神经元损伤,抑制海马CA1区LTP的产生,从而降低正常学习记忆能力;(2)外源性H2S可减轻海洛因依赖对大鼠海马神经元的损伤,易化海马CA1区LTP的产生,改善海洛因依赖导致的正常学习记忆能力的降低。     

外源性硫化氢保护实验性癫痫持续状态大鼠海马神经元作用的研究

目的:为研究外源性硫化氢(H_2S)对实验性癫痫持续状态(status of epilepticus,SE)大鼠海马神经元的保护作用,我们用供体Na HS对氯化锂-匹罗卡品所致幼鼠SE海马神经元的影响,并对SE引起的脑损伤进行靶点干预。方法:用氯化锂-匹罗卡品建立大鼠SE模型,并分为正常+Na HS组,癫痫组,癫痫+Na HS组和癫痫+羟胺组,另设正常组(对照组),每组6只。用比色法测定血浆和海马H_2S浓度,用Real-Time PCR检测海马胱硫醚-β合酶(CBS)基因mRNA表达,用HE染色和Nissl染色观察海马神经元形态。结果:癫痫组血浆和海马组织H_2S浓度和CBS mRNA表达明显低于正常组(P0.01),癫痫+Na HS组血浆和海马组织H_2S浓度和CBS mRNA表达明显高于癫痫组(P0.01),癫痫+羟胺组血浆和海马组织H_2S浓度和CBS mRNA表达显著低于癫痫组(P0.05)。HE染色显示,癫痫组海马CA3区锥体细胞明显减少,细胞层次紊乱,形态不规则;尼氏染色显示,癫痫组海马CA3区尼氏体明显减少,锥体细胞排列紊乱;与癫痫组比较,癫痫+Na HS组海马尼氏体缺失和锥体细胞排列紊乱明显改善。结论:外源性H_2S对实验性癫痫持续状态大鼠海马组织CBS mRNA表达具有上调作用,并提高血浆和海马组织H_2S含量。同时,外源性H_2S对实验性癫痫大鼠海马组织神经元具有保护作用。     

低浓度神经生长因子对癫痫大鼠空间学习记忆能力的影响及机制研究

目的:探讨低浓度神经生长因子(NGF)对戊四氮(PTZ)点燃癫痫大鼠空间学习记忆能力的影响及其可能机制。方法:将SD雄性大鼠随机分为对照组、癫痫模型组和NGF组。采用PTZ慢性点燃SD大鼠癫痫模型,并对模型组大鼠腹腔注射低浓度NGF,大体观察各组大鼠癫痫行为学;应用Morris水迷宫检测大鼠空间学习记忆能力,应用Western Blotting检测各组大鼠海马转录因子CREB、磷酸化的CREB(p-CREB)和突触后蛋白PSD95的表达变化。结果:模型组和NGF组大鼠出现典型癫痫发作的行为学改变,后者经NGF干预后未出现明显改善。模型组大鼠空间学习记忆能力受损,逃避潜伏期延长,目标象限停留时间较短(P<0.05),p-CREB和PSD95表达水平较对照组和NGF组降低(P<0.05);NGF组大鼠空间学习记忆能力改善,其逃避潜伏期变短,目标象限停留时间明显延长,p-CREB和PSD95表达水平接近对照组。结论:PTZ点燃癫痫大鼠的空间学习记忆能力受损;NGF可以通过提高p-CREB和PSD95的表达水平改善癫痫大鼠的空间学习记忆能力。     

Ghrelin对糖尿病大鼠海马神经元凋亡及其认知功能的影响

目的观察Ghrelin对糖尿病大鼠海马神经元凋亡及其认知功能的影响。方法 40只雄性SD大鼠随机均分为对照组、糖尿病组、糖尿病+Ghrelin组和糖尿病+Ghrelin+D-lys3-GHRP-6组,每组10只。建立STZ糖尿病模型,open-field实验排除合并抑郁症的糖尿病大鼠,Morris水迷宫测试学习与记忆能力,RT-PCR检测海马caspase-3mRNA的表达,免疫组化检测海马神经元caspase-3和BCL-xl蛋白表达,原位末端标记法检测海马神经元的凋亡。结果与对照组大鼠相比,糖尿病组和糖尿病+Ghrelin+D-lys3-GHRP-6组学习与记忆能力显著受损(P<0.05),海马部位的caspase-3 mRNA及蛋白表达明显升高(P<0.05),BCL-xl蛋白表达显著下降(P<0.05),海马神经元的凋亡增加了49%(P<0.05)。糖尿病+Ghrelin组学习和记忆成绩明显优于糖尿病组(P<0.05),其海马部位的caspase-3 mRNA及蛋白表达显著下降(P<0.05),BCL-xl蛋白表达明显升高(P<0.05),海马神经元的凋亡减少了42%。结论 Ghrelin对糖尿病大鼠...     

慢性强迫游泳应激抑郁模型大鼠海马钙离子浓度和c-fos表达的改变

目的:观察慢性强迫游泳应激模型大鼠海马区[Ca2+]i和c-fos/Fos的变化,探讨慢性应激抑郁症与海马相关的发病机制。方法:选用雄性成年Wistar大鼠80只,将大鼠随机分为正常对照组(n=19)、急性对照组(n=12)和模型组(n=49),建立慢性强迫游泳应激抑郁模型,通过糖水偏好实验和开场实验对大鼠进行行为学测试。采用荧光分光光度法测定海马内[Ca2+]i浓度,免疫印迹技术和逆转录-聚合酶链式反应检测Fos和c-fos的表达变化。结果:与正常对照组大鼠相比较:(1)模型组大鼠相对糖水消耗量、糖水偏好百分比、直立次数和体重增长率均降低(P0.01,P0.05);(2)模型组大鼠各个时间点海马神经元[Ca2+]i增高(P0.01);(3)模型组大鼠海马Fos在应激后(0.5,1,2,4h)表达增强(P0.01),c-fosmRNA在应激后(0.5,1,2,4h)转录增强(P0.01)。与急性对照组相比较,模型组Fos蛋白表达高峰提前,表达量降低(P0.05)。结论:海马[Ca2']i及c-fos/Fos的表达变化,可能参与了抑郁症的发病过程。     

外源性硫化氢对APP/PS1小鼠tau蛋白磷酸化及对PI3K/Akt/GSK-3β信号通路的影响

目的探讨外源性硫化氢(H2S)对APP/PS1转基因小鼠海马区tau蛋白磷酸化及对PI3K/Akt/GSK-3β信号通路的影响。方法将7月龄APP/PS1小鼠20只,随机分为模型组及硫氢化钠(NaHS)组,每组10只;另取同龄C57BL/6小鼠作为对照组,连续腹腔注射NaHS共6周,每天1次。HE染色检测脑组织病理学改变;TUNEL检测小鼠海马区神经细胞凋亡情况;Morris水迷宫检测各组小鼠的学习与记忆能力;免疫组化检测各组小鼠海马区tau、p-tau(Ser-202)、p-tau(Thr-231)及p-tau(Ser-396)蛋白表达情况;Western blot检测PI3K、Akt、GSK-3β、p-Akt及p-GSK-3β蛋白的表达。结果与模型组相比,NaHS组小鼠脑组织病理损伤明显改善;小鼠海马区神经细胞凋亡数量明显降低;小鼠逃避潜伏期明显缩短,单位时间内目标象限停留时间延长,穿台次数增加;p-tau(Ser-202)、p-tau(Thr-231)及p-tau(Ser-396)蛋白表达明显降低;同时,PI3K、p-Akt蛋白水平增加,而p-GSK-3β蛋白水平降低,差异有统计学意义(P0.05)。结论 NaHS可减少神经细胞凋亡,抑制tau蛋白磷酸化,改善学习记忆能力,其机制可能与调控PI3K/Akt/GSK-3β信号通路活性有关。     

戊四氮诱导癫痫大鼠空间学习记忆受损及海马突触后致密物95表达减少

目的探讨戊四氮诱导癫痫对大鼠空间学习记忆功能的影响及海马突触后致密物95(PSD-95)的表达变化。方法戊四氮(PTZ)腹腔注射诱导慢性癫痫(CEP)模型,采用Morris水迷宫对两组大鼠进行行为学检测,运用免疫组织化学方法观察海马CA1、CA3区PSD-95的表达,反转录聚合酶链反应(RT-PCR)方法检测大鼠海马PSD-95mRNA的表达。结果癫痫组大鼠空间学习记忆能力受损;其海马CA1、CA3区PSD-95免疫阳性产物较对照组明显减少(P<0.05),同时伴有海马PSD-95mRNA表达下降(P<0.01)。结论戊四氮诱导癫痫大鼠空间学习记忆受损可能与海马神经元PSD-95的表达减少有关。     

2000 μW/cm2电磁辐射对大鼠海马NR2A蛋白及其mRNA表达的影响

目的:探讨2000 μW/cm2 电磁辐射对大鼠海马N-甲基-D-门冬氨酸受体亚单位2A(NR2A)蛋白及其mRNA水平表达的影响,揭示电磁辐射对大鼠学习记忆功能的损伤机制.方法:实验分为空白对照组,假辐射组,1 h/d、2 h/d、3 h/d辐射组.将辐射组大鼠固定体位,头部接受功率密度为2000 μW/cm2 的近场辐射,连续辐射30 d.通过Morris水迷宫检测大鼠的空间学习记忆能力,采用免疫组化法和Westernblot法检测大鼠海马组织NR2A蛋白表达的变化,RT-PCR法检测大鼠海马组织NR2A mRNA表达的变化.结果:假辐射组大鼠各项指标与空白对照组相比均无统计学差异(P>0.05);而各辐射组大鼠寻找安全平台的逃避潜伏期较空白对照组明显延长(P<0.05);各辐射组大鼠海马神经元排列紊乱,NR2A阳性细胞比率显著下降,海马组织NR2A蛋白及其mRNA表达水平明显降低(P<0.05).结论:2000 μW/cm2 电磁辐射可导致大鼠学习记忆功能下降,其机制可能与大鼠海马组织NR2A蛋白及其mRNA的表达降低有关.     

颈动脉狭窄影响大鼠认知功能及海马神经元凋亡

目的:研究改善颈动脉狭窄对大鼠认知功能、海马神经元凋亡及bcl-2、Bax蛋白表达的影响.方法:采用SD大鼠制作颈动脉狭窄模型,2周后将颈动脉狭窄解除,4周后各组采用Morris水迷宫检测记忆能力、HE染色观察神经元形态学变化、TUNEL法观察海马神经元凋亡、免疫组织化学检测Bcl-2、Bax蛋白表达.结果:对照组与假手术组比较,大鼠记忆能力明显下降(P<0.01),神经细胞凋亡率明显增高(P<0.01),Bcl-2和Bax免疫阳性细胞数增多(P<0.01),改善狭窄组较对照组记忆能力明显改善(P<0.01),神经细胞凋亡率明显低于对照组(P<0.05),Bcl-2免疫阳性细胞数明显增多(P<0.05),Bax免疫阳性细胞数明显减少(P<0.05).结论:改善颈动脉狭窄可提高大鼠海马Bcl-2蛋白的表达,抑制海马神经细胞凋亡,改善认知功能障碍.     

PTSD大鼠海马CA1区和前额叶皮层突触小泡蛋白的表达

目的:观察创伤后应激障碍(posttraumatic stress disorder,PTSD)大鼠海马CA1区和前额叶皮层(prefrontal cortex,PFC)突触小泡蛋白(synaptophysin)的表达,探讨PTSD大鼠空间记忆损伤的机制。方法:健康成年SD大鼠36只,随机分为正常对照组和模型组,每组18只。模型组采用单次延长应激(single prolonged stress,SPS)构建PTSD大鼠模型。Morris水迷宫实验检测2组大鼠的学习记忆能力,利用免疫组化、Western blot和免疫荧光实验检测海马CA1区和PFC突触小泡蛋白的表达情况。结果:经过Morris水迷宫实验,模型组大鼠从第2天开始逃避平台的潜伏期较对照组均显著延长(P 0.01),目标象限的停留时间均明显降低(P 0.01),穿越原平台位置的次数也明显减少(P 0.01)。在免疫组化、Western blot和免疫荧光实验中,模型组大鼠海马CA1区和PFC突触小泡蛋白的表达较对照组均明显减少(P 0.05或P 0.01)。结论:创伤后应激障碍大鼠空间记忆能力减退,可能与海马CA1区和PFC突触小泡蛋白的表达减少有关。     

Rates of oxygen consumption and of anaerobic glycolysis in renal cortex and medulla of adult and new-born rats and guinea-pigs

1. Rates of oxygen uptake and of anaerobic glycolysis were estimated in slices from the renal cortex and medulla (a) of adult rats and guinea-pigs, (b) of new-born (1-, 5- and 21-day-old) rats and of guinea-pigs of 1, 12, 21, 24 and 120 hr age.2. In the adult rat, Q(O2) values for the cortex were 12.55 +/- 0.20 (22) and for the medulla: 8.56 +/- 0.17 (22) mul./hr.mg dry weight, while in the new-born rat (24 hr old) they were 10.99 +/- 0.46 (12) and 9.33 +/- 0.18 (9) mul./hr.mg dry weight respectively.3. Values for Q(CO2) (N2) (anaerobic glycolysis) in the 14 hr old new-born rat were in the renal cortex 9.65 +/- 0.35 (5) and in the medulla 7.39 +/- 0.43 (5) mul./hr.mg dry weight; while in the adult they were 2.25 +/- 0.08 (16) and 5.76 +/- 0.14 (16) mul./hr.mg dry weight, respectively.4. In the adult guinea-pig values for Q(CO2) (N2) were of the same order as in the adult rat, though the rate of O(2) uptake was for the cortex 8.12 +/- 0.22 (12) and for the medulla 5.02 +/- 0.23 (11) mul./hr.mg dry weight.5. Though the Q(O2) values in the renal cortex and medulla were smaller in the 1 hr old new-born guinea-pig, they were already increasing in the 12 hr old neonate.6. The results are discussed in the light of enzyme changes occurring during the process of maturation of the nephron as indicated by histochemical observations.     

Modes of reinforcement and gender and culture of experimenter and subject: effects of "alien" and external reinforcement for Japanese and American men and women

In this study, we examined external and "alien" reinforcement (ER and AR. respectively) as a factor in social learning, and studied the combined effects of culture and reinforcement mode. A female (Experiment 1) and a male (Experiment 2) experimenters conducted experimental sessions. Both men and women, who grew up in the same culture as the experimenter, participated and performed the experimental task. A three-way interaction effect of experimenter gender, culture, and reinforcement mode was found on task performance. And the effect was more pronounced for a Japanese experimenter. A female and a male experimenters conducted Experiments 3 and 4, respectively; however participants this time were men and women who grew up in different cultures than the experimenter. Results indicated that the pattern of the subject gender and reinforcement mode interaction effect, when the experimenter was Japanese with American subjects, was exactly opposite to that when the experimenter was American. These experiments showed that AR was as effective for social learning as ER, and that the cultural backgrounds of experimenter and subject influenced AR and ER effectiveness.     

Timing and intensity of early fevers and the development of allergies and asthma

BACKGROUND: Early childhood fevers appear to protect against later allergies and asthma. What is not known is the time in which fevers exert this effect and whether the degree of temperature increase is important. OBJECTIVE: We sought to examine the relationship between the time and degree of early fevers and later allergies and asthma. METHODS: Eight hundred thirty-five children from southeast Michigan were enrolled at birth. Clinic records from their first 2 years were abstracted for episodes of fever. At age 6 to 7 years, children underwent allergy testing. We examined fevers occurring within 6-month intervals in the first 2 years of life and outcomes at age 6 to 7 years. The primary outcome measures were allergic sensitization, asthma, asthma with allergic sensitization, and asthma without allergic sensitization. RESULTS: In the unadjusted analysis each episode of fever between 7 and 12 months of age was associated with a lower odds of allergic sensitization (odds ratio [OR], 0.71; 95% CI, 0.54-0.93) and asthma with allergic sensitization (OR, 0.43; 95% CI, 0.21-0.90) at age 6 to 7 years. Likewise, every 1 degrees C increase in the maximum temperature between 7 and 12 months was associated with a lower odds of allergic sensitization (OR, 0.77; 95% CI, 0.61-0.96) and asthma with allergic sensitization (OR, 0.62; 95% CI, 0.40-0.94). After adjusting for potential confounders, each episode of fever between 7 and 12 months was associated with a lower likelihood of asthma with allergic sensitization (adjusted OR, 0.33; 95% CI, 0.11-0.94) at age 6 to 7 years. CONCLUSIONS: Both the timing and intensity of childhood fevers appear to be important factors in the development of allergies and asthma.     

纳米水平分子成像与诊疗一体化研究进展与挑战

分子成像能以非侵入性的方式重现活体细胞的生理功能和生物学过程,提高疾病的早期和特异性诊断水平。纳米颗粒/材料具有物理性质可控性高、易于表面修饰、血液循环时间长和可功能化等优点,在疾病诊断与治疗中显示出巨大潜力。但如何阐明纳米材料多功能间的内在联系、解决其代谢及安全性等关键机制难题、实现纳米颗粒/材料多功能性到临床多功能...