Proliferation and differentiation of neural precursors in hippocampus and dentate gyrus after intracerebral hemorrhage in adult rats

目的:观察成年大鼠脑出血后海马齿状回神经前体细胞的增殖与分化,探讨脑出血后神经前体细胞的变化规律.方法:制作大鼠脑出血模型,5-溴脱氧尿嘧啶核苷(BrdU)腹腔注射标记增殖细胞,用免疫组织化学法检测大鼠海马齿状回BrdU、神经元核抗原(NeuN)、胶质纤维酸性蛋白(GFAP)阳性细胞数的变化.结果:正常组和假手术组大鼠海马齿状回均有少量BrdU阳性细胞,脑出血后大鼠各时间段的BrdU阳性细胞均较正常组和假手术组增加,7d组达到峰值后逐渐下降,28 d组仍高于正常组和假手术组.正常成年大鼠海马齿状回可见少量BrdU/NeuN和BrdU/GFAP双标阳性细胞,脑出血后双标阳性细胞数较正常组增加.结论:脑出血后大鼠海马齿状回神经前体细胞增殖明显,且可以向神经元和神经胶质细胞分化.     

BMP4参与海人酸损伤后成年大鼠海马齿状回颗粒细胞增殖及胶质增生

目的探讨海人酸（KA）侧脑室注射致大鼠海马损伤后骨形成蛋白-4（BMP4）的表达变化及其与颗粒细胞增殖和胶质细胞增生的关系。方法将成年大鼠分为对照组与实验组。侧脑室注射KA7d后,用尼氏染色检测海马神经元丢失,用免疫组织化学与原位杂交的方法检测海马齿状回BMP4mRNA阳性细胞与BrdU标记细胞、GFAP阳性细胞数的变化。结果正常成年大鼠BMP4mRNA阳性细胞主要分布于海马齿状回的门区、颗粒下层、CA3、CAI区。BrdU标记细胞主要分布在齿状回颗粒下层。GFAP阳性细胞主要分布在齿状回、CA3区。在KA侧脑室注射致海马损伤后7d,海马CA3、CA4区神经元丢失明显,BMP4mRNA阳性细胞与BrdU、GFAP阳性细胞均明显增加。结论KA侧脑室注射致海马损伤后,成年大鼠海马齿状回颗粒细胞增殖增强和胶质增生可能与BMP4表达增加有关。     

成年大鼠脑损伤后海马新生神经元功能特点的研究

目的：观察弥漫性脑损伤后海马齿状回新生神经元GAD67和Fos蛋白的表达，探讨海马齿状回新生神经元的功能特点。方法：参考Marmarou方法制作大鼠弥漫性脑损伤模型，采用BrdU标记和免疫荧光组织化学方法并结合激光共聚焦显微镜技术观察海马齿状回中BrdU阳性细胞GAD67的表达和二次致伤后Fos蛋白的表达情况。结果：①成年大鼠弥漫性脑损伤后海马齿状回颗粒细胞层中的BrdU免疫阳性细胞可表达GAD67，而位于亚颗粒增生带的BrdU免疫阳性细胞未见GAD67表达；②在病理刺激下，成年大鼠弥漫性脑损伤后齿状回颗粒细胞层内的BrdU免疫阳性细胞可表达Fos蛋白。结论：弥漫性脑损伤后齿状回颗粒细胞层中的新生神经元不仅可以表达神经活性递质而且能够被病理刺激激活，具有与成熟神经元相似的功能特点。     

怀孕可增加小鼠海马齿状回的细胞增殖和神经发生

目的：观察怀孕对小鼠海马齿状回（DG）和脑室下层（SVZ）的细胞增殖和神经发生的影响。方法：5－溴－2－脱氧尿苷（BrdU)标记新生细胞结合免疫组织化学方法对脑切片进行BrdU、TuJ1及GFAP单标或双标染色。结果：怀孕小鼠齿状回的细胞增殖和神经发生明显高于正常未孕成年雌性小鼠，脑室下层中细胞增殖的数目在两者却无明显差异。在齿状回新生的细胞中大约有80％为新生的神经元，3％－5％为神经胶质细胞。结论：成年小鼠海马齿状回的细胞增殖和神经发生可能因怀孕而显著增多，这些新生的细胞对海马的功能可能有重要的影响。     

氯化锂对成年小鼠海马神经发生的影响

目的：观察氯化锂(LiCl)对成年小鼠海马细胞增殖与神经发生的影响。方法：用5-溴-2-脱氧尿核苷(BrdU)标记新生细胞，免疫组化染色后统计新生细胞数量；应用BrdU与抗微管蛋白单克隆抗体(JuJI)／抗胶质纤维酸性蛋白多克隆抗体(GFAP)双标记，鉴别出BrdU阳性细胞的细胞类型。结果：LiCl组小鼠海马齿状回细胞增殖与神经发生明显强于对照组；新增殖的细胞约有70％为神经元，5％左右为神经胶质细胞。结论：LiCl增强了成年小鼠海马齿状回的细胞增殖与神经发生，这一功能对于中枢神经系统退行性疾病的预防与治疗可能有重要的意义。     

次声激活小胶质细胞抑制成年大鼠海马神经干细胞增殖

目的:探讨次声对成年大鼠海马齿状回颗粒细胞下层(subgranular zone,SGZ)神经干细胞增殖抑制作用的细胞学机制。方法:成年雄性Sprague-Dawley大鼠置于次声压力舱,连续暴露于16 Hz、130 dB次声7 d(2h/d)后,给与小胶质细胞抑制剂米诺环素(50 mg/kg,药物组,n=16)或等体积生理盐水(对照组,n=16),同时设立不经次声作用的正常对照组(n=16);分别于1、3、7和14 d处死大鼠,利用免疫组织化学法以Iba1、OX42标记小胶质细胞,BrdU标记增殖的神经干细胞。结果:小胶质细胞在SGZ区分布较为密集;与正常对照组相比,次声暴露后3 d时OX42免疫反应性明显增强、SGZ区BrdU阳性细胞数目减少最为明显(P0.01);米诺环素可显著改善次声暴露后BrdU阳性细胞数目的减少(P0.01)。结论:小胶质细胞活化参与次声抑制成年大鼠海马SGZ区神经干细胞的增殖。     

跑台运动及周龄对大鼠海马神经发生的影响

目的探讨运动及其周龄对大鼠海马神经发生的影响。方法将40只雄性SD大鼠随机分为7周龄安静对照组、7周龄小强度运动组、9周龄安静对照组和9周龄小强度运动组。腹腔注射BrdU于大鼠,持续注射6d。采用免疫组织荧光染色技术,检测各组大鼠海马齿状回内新生细胞和新生神经元数量。结果各组动物海马齿状回BrdU免疫阳性(BrdU+)细胞数目为:7周龄安静对照组50.66±10.54,7周龄小强度运动组74.21±17.00,9周龄安静对照组37.62±9.02,9周龄小强度运动组46.01±10.82。各组动物海马齿状回BrdU++NeuN+细胞数目为:7周龄安静对照组22.54±6.76,7周龄小强度运动组33.38±8.26,9周龄安静对照组15.26±4.42,9周龄小强度运动组17.61±3.86。结论运动促进海马齿状回神经发生,随着周龄的增长而减弱。     

氯化锂促进不同年龄成年小鼠齿状回细胞增殖与神经发生

目的观察氯化锂(LiCI)对不同年龄成年小鼠齿状回细胞增殖与神经发生的影响。方法以氯化锂喂养动物，用5-溴-2’-脱氧尿核苷(BrdU)标记新生细胞，免疫组织化学染色后统计新生细胞数量；应用BrdU与TuJl／GFAP双标记，鉴别出BrdU阳性细胞的细胞类型。结果不同年龄成年小鼠齿状回的BrdU阳性细胞形态无明显差别，48周龄组阳性细胞的数量明显低于8周龄组；LiCI组小鼠新增殖细胞明显多于对照组，其中约有70％为神经元，4％～5％左右为神经胶质细胞。结论服用LiCI可显著增强成年小鼠齿状回的细胞增殖与神经发生，部分逆转其随年龄增长而逐渐减低的趋势，对于中枢神经系统退行性疾病的预防与治疗可能有重要的意义。     

液化石油气中毒对小鼠齿状回及室管膜下区神经发生的影响

目的:探讨液化石油气急性中毒对小鼠海马齿状回及侧脑室室管膜下区神经发生的影响。方法:选择健康成年昆明小鼠随机分三组,分别为对照组,液化石油气(LPG)高、低剂量中毒组。使用密闭中毒箱行染毒实验。用Morris水迷宫训练测试其空间学习与记忆能力;腹腔注射5-溴脱氧尿苷(BrdU)后通过免疫组织化学方法来显示BrdU阳性细胞。结果:两个中毒组动物的学习记忆能力均弱于对照组(P<0.01),齿状回和室管膜下区内BrdU阳性细胞数目也低于对照组(P<0.01)。结论:液化石油气急性中毒通过抑制齿状回和室管膜下区的神经发生,影响小鼠的学习记忆能力和脑损伤后修复。     

切割穹窿海马伞后海马齿状回内Lhx8的表达变化及其对RGCs向胆碱能神经元分化的影响

目的:明确Lhx8在SD大鼠切割穹窿海马伞后海马齿状回颗粒下层和门区中的表达变化。方法:切割SD大鼠穹窿海马伞,成功制备海马去神经支配动物模型后,通过Western Blot的方法检测切割后第1、3、7、14、21、28 d海马中Lhx8蛋白的表达变化;通过免疫组织化学方法检测切割后第7天海马齿状回颗粒下层和门区中Lhx8阳性细胞的表达定位,并通过免疫荧光化学方法检测Lhx8/ChAT双标阳性细胞的共定位情况;切割SD大鼠穹窿海马伞并制备海马提取液,将其加入至细胞培养液中,模拟体内海马神经再生微环境,检测培养的海马放射状胶质细胞(radial slia cells,RGCs)向胆碱能神经元分化的情况。结果:切割穹窿海马伞后第7 d,Lhx8蛋白表达量较其他各时相点明显增高;海马齿状回颗粒下层和门区中Lhx8阳性细胞数目和光密度也明显高于正常侧,Lhx8/ChAT双标阳性细胞数目也较正常侧增多;体外细胞培养,切割穹窿海马伞侧海马提取液也较正常侧海马提取液更能促进海马放射状胶质细胞向胆碱能神经元的分化。结论:切割穹窿海马伞后,Lhx8表达明显上调,与海马齿状回的胆碱能神经再生有关。     

神经发生对小鼠学习记忆能力的影响

本研究探讨神经发生对学习记忆能力的影响。选择健康成年昆明小鼠随机分7组,分别为生理盐水对照组,酸性成纤维细胞生长因子(aFGF)高、中、低剂量组,甲氨喋呤(MTX)高、中、低剂量组。使用脑立体定位仪行侧脑室埋管手术及侧脑室微量注射。用Morris水迷宫训练测试其空间学习与记忆能力;腹腔注射5-溴脱氧尿苷(BrdU)后通过免疫组织化学方法来显示Br-dU阳性细胞。结果表明,aFGF各剂量组学习记忆能力均强于生理盐水对照组;MTX高剂量组学习记忆能力显著低于生理盐水对照组。免疫组织化学结果显示aFGF各剂量组齿状回内BrdU阳性细胞数目显著高于对照组;而MTX高剂量组齿状回BrdU阳性细胞较之显著减少。结果提示,aFGF和MTX可能通过促进或抑制齿状回的神经发生,从而影响小鼠的学习与记忆能力。     

Involvement of cyclooxygenase-2 in lipopolysaccharide-induced impairment of the newborn cell survival in the adult mouse dentate gyrus

There is growing evidence indicating that neurogenesis in adulthood is influenced by certain types of the central diseases such as neuroinflammation, however, its mechanism is not fully understood. This study was, therefore, designed to examine the effects of lipopolysaccharide (LPS), a bacterial endotoxin known to cause the neuroinflammation, on the neurogenesis in the dentate gyrus of adult mice using the bromodeoxyuridine (BrdU) -pulse chase method. LPS failed to affect the number of BrdU-labeled cells in the dentate gyrus 2 h after BrdU injection, indicating no effects of LPS on the proliferation of the neural stem cells (NSCs). On the other hand, we found that LPS dose-dependently (0.1, 0.5, 1 mg/kg) decreased the number of BrdU-labeled cells 7 and 21 days after BrdU injection. We also observed that LPS increased cell death in the dentate gyrus using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining, suggesting that LPS impaired the survival of newborn cells derived from the NSCs. The double-immunostaining for BrdU and specific cell type markers revealed that LPS did not alter the commitment of the NSCs to the neurons and astrocytes. The systemic injection of indomethacin, a non-selective cyclooxygenase (COX) inhibitor, and NS398, a selective COX-2 inhibitor, but not SC560, a selective COX-1 inhibitor, did not only ameliorate LPS-induced suppression of the newborn cell survival, they fully protected against the LPS effect. Furthermore, the central injection of NS398 also ameliorated LPS-induced suppression of the newborn cell survival in the dentate gyrus. The treatment with LPS increased the expression of COX-2 protein 7 h and 7 days after the injection in the dentate gyrus. These results suggest that LPS impairs the survival of newly generated cells derived from the NSCs in the dentate gyrus without affecting the differentiation fate, and these effects of LPS were mediated presumably by COX-2 expression in the dentate gyrus.     

Ischemia induces cell proliferation and neurogenesis in the gerbil hippocampus in response to neuronal death

We studied hippocampal cellular proliferation and neurogenesis processes in a model of transient global cerebral ischemia in gerbils by labelling dividing cells with 5'-Bromo-2'-deoxyuridine (BrdU). Surrounding the region of selective neuronal death (CA1 pyramidal layer of the hippocampus), an important increase in reactive astrocytes and BrdU-labelled cells was detected 5 days after ischemia. A similar result was found in the dentate gyrus (DG) 12 days after ischemia. The differentiation of the BrdU+ cells was investigated 28 days after BrdU administration by analyzing the morphology, anatomic localization and cell phenotype by triple fluorescent labelling (BrdU, adult neural marker NeuN and DNA marker TOPRO-3) using confocal laser-scanning microscopy. This analysis showed increased neurogenesis in the DG in case of ischemia and triple positive labelling in some newborn cells in CA1. Seven brain hemispheres from gerbils subjected to ischemia did not develop CA1 neuronal death; hippocampus from these hemispheres did not show any of the above mentioned findings. Our results indicate that ischemia triggers proliferation in CA1 and neurogenesis in the DG in response to CA1 pyramidal neuronal death, independently of the reduced cerebral blood flow or the cell migration from subventricular zone (SVZ).     

不同年龄脑出血大鼠海马齿状回神经干细胞增殖与分化差异的比较

BACKGROUND:Cerebral hemorrhage can activate the proliferation and differentiation of neural stem cells in the dentate gyrus of the hippocampus. Through continuous differentiation and proliferation, endogenous neural stem cells can gradually replace aging and damaged neurons, thus protecting the brain structure. OBJECTIVE:To compare the difference of the proliferation and differentiation of neural stem cells in the dentate gyrus of the hippocampus of rats with different ages. METHODS:Ninety-six adult rats and 96 aged rats were randomly divided into normal group (n=18 per group), sham operation group (n=12 per group) and cerebral hemorrhage group (model group, n=66 per group), respectively. Cerebral hemorrhage models were made in the two model groups in which, the rats were subjected to cerebral hemorrhage for 6, 24, 48, 72 hours and 7 days, respectively. Then, brain tissues were collected to measure brain water content. BrdU/NeuN and BrdU/GFAP double staining were performed at 3, 7, 14, 21, 28 days after surgery to calculate the number of positive cells. RESULTS AND CONCLUSION:For both adult and aged rats, the brain water content was significantly higher than that in the normal group and sham operation group (P < 0.05), while in the normal and sham operation groups, the brain water content was significantly lower in the aged rats than the adult rats (P  < 0.05). The number of bilateral BrdU-positive cells in the adult and aged model groups was significantly higher than that in the corresponding normal and sham operation groups (P  < 0.05), and moreover, the positive cell number at the hemorrhage side was significantly higher than that at the opposite side (P < 0.05). In addition, the number of BrdU-positive cells at the hemorrhage side in the adult rats was significantly higher than that in the aged rats at different time after cerebral hemorrhage (P  < 0.05). Results from immunohistochemical double staining showed that the BrdU/NeuN and BrdU/GFAP expression in the hippocampal dentate gyrus of adult rats with cerebral hemorrhage was significantly higher than that of normal adult rats. All these experimental results show that there are a few neural stem cells proliferating in the hippocampal dentate gyrus of normal rats, and the proliferation ability is stronger in the adult rats than the aged rats. Cerebral hemorrhage can significantly strengthen the proliferation of neural stem cells in the dentate gyrus in the adult rats compared with the aged rats.     

Developmental exposure to 3,4-methylenedioxymethamphetamine results in downregulation of neurogenesis in the adult mouse hippocampus

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a powerful releaser of 5-HT and chronic use of this drug can cause depletion of monoamines. Recently, concerns about the risk of adult brain damage due to fetal exposure to MDMA have been raised. We investigated whether developmental MDMA exposure affected adult neurogenesis in C57 black/6 mice. MDMA (1.25 or 20 mg/kg, p.o.) or vehicle was administered daily to the mother from prenatal 6th day to postnatal 21st day. When the offspring were 11 weeks old, they were injected with 5-bromo-2'-deoxyuridine (BrdU) (120 mg/kg, i.p.) once a day for 4 days. After 24 h or 28 days, the animals were killed to count the BrdU-positive cells in the dentate gyrus. At 24 h after the last BrdU injection, the number of BrdU-positive cells in the offspring developmentally exposed to MDMA was significantly lower than that of the control group. At 28 days post-BrdU labeling, BrdU-positive cells in the dentate gyrus of female offspring with developmental exposure to high dose MDMA were significantly fewer compared with the control group. In addition, most BrdU-positive cells were co-labeled with the mature neuronal marker, neuronal nuclei, while a few BrdU-labeled cells were merged with an astrocyte marker. Our results suggest that developmental exposure to MDMA can result in decreases in the proliferation and survival of mature newborn cells in the adult dentate gyrus.     

营养不良可增加幼鼠齿状回颗粒下层的细胞增殖和神经生发(英文)

为了观察营养不良对幼鼠海马齿状回 (DG)和脑室下层 (SVZ)的细胞增殖和神经发生的影响 ,采用 5 -溴 -2 -脱氧尿苷(Brd U)标记结合免疫组织化学方法对脑切片分别进行 Brd U、Tu J1(β tubulin,β微管蛋白 )及 GFAP(胶质纤维酸性蛋白 )反应或双重反应。结果表明 ,营养不良幼鼠齿状回的细胞增殖和神经生发明显高于营养良好的幼鼠而脑室下层的细胞增殖数量在两者却无明显差异。在齿状回 ,新生的细胞中大约有 5 0 %为新生的神经元 ,10～ 2 0 %为神经胶质细胞。本文结果提示 ,幼鼠海马齿状回的细胞增殖和神经生发可能因营养不良而增加 ,这些新生的细胞可能对日后某些海马依赖性行为产生一定的影响     

Proliferation and differentiation of progenitor cells in the cortex and the subventricular zone in the adult rat after focal cerebral ischemia

Progenitor cells in the subventricular zone of the lateral ventricle and in the dentate gyrus of the hippocampus can proliferate throughout the life of the animal. To examine the proliferation and fate of progenitor cells in the subventricular zone and dentate gyrus after focal cerebral ischemia, we measured the temporal and spatial profiles of proliferation of cells and the phenotypic fate of proliferating cells in ischemic brain in a model of embolic middle cerebral artery occlusion in the adult rat. Proliferating cells were labeled by injection of bromodeoxyuridine (BrdU) in a pulse or a cumulative protocol. To determine the temporal profile of proliferating cells, ischemic rats were injected with BrdU every 4 h for 12 h on the day preceding death. Rats were killed 2-14 days after ischemia. We observed significant increases in numbers of proliferating cells in the ipsilateral cortex and subventricular zone 2-14 days with a peak at 7 days after ischemia compared with the control group. To maximize labeling of proliferating cells, a single daily injection of BrdU was administered over a 14-day period starting the day after ischemia. Rats were killed either 2 h or 28 days after the last injection of BrdU. A significant increase in numbers of BrdU immunoreactive cells in the subventricular zone was coincident with a significant increase in numbers of BrdU immunoreactive cells in the olfactory bulb 14 days after ischemia and numbers of BrdU immunoreactive cells did not significantly increase in the dentate gyrus. However, 28 days after the last labeling, the number of BrdU labeled cells decreased by 90% compared with number at 14 days. Clusters of BrdU labeled cells were present in the cortex distal to the infarction. Numerous cells immunostained for the polysialylated form of the neuronal cell adhesion molecule were detected in the ipsilateral subventricular zone. Only 6% of BrdU labeled cells exhibited glial fibrillary acidic protein immunoreactivity in the cortex and subcortex and no BrdU labeled cells expressed neuronal protein markers (neural nuclear protein and microtubule associated protein-2). From these data we suggest that focal cerebral ischemia induces transient and regional specific increases in cell proliferation in the ipsilateral hemisphere and that proliferating progenitor cells may exist in the adult cortex.     

I.c.v. administration of orexin-A induces an antidepressive-like effect through hippocampal cell proliferation

A decrease in orexin-A (OX-A) levels has been reported to be associated with depression. It is also well known that stress and depression can disrupt neurogenesis in the dentate gyrus of the hippocampus; however, it is unclear how OX-A is involved in depression and/or neurogenesis. In the present study, we investigated the effect of i.c.v. administration of OX-A on the forced swimming test (FST), an accepted behavioral screen of antidepressant-like activity, and on the cell proliferation with bromodeoxyuridine (BrdU) in the dentate gyrus at 4 days after i.c.v. administration of OX-A. OX-A administration (140 pmol/mouse) led to a significant reduction in animal immobility in the FST, without affecting spontaneous locomotor activities or serum corticosterone levels. In addition, the number of BrdU-positive cells in the dentate gyrus was significantly increased in OX-A-treated mice in vivo; however, OX-A did not affect the percentage of doublecortin-positive cells in the dentate gyrus. The proliferation of neural progenitor cells derived from rat fetal brain was not affected by OX-A treatment in vitro, and the orexin receptor 1 (OXR1) protein was not expressed in these cells. Treatment with the OXR1 antagonist SB-334867 (30 mg/kg, i.p.) blocked both the OX-A-induced decrease in the immobility of FST and increase in BrdU-positive. Moreover, the OX-A-induced increase in neuropeptide Y (NPY)-positive cells in the hilus of the dentate gyrus was blocked by SB-334867. These results suggest that OX-A induces an antidepressive-like effect, at least in part, via the enhancement of cell proliferation in the dentate gyrus. These effects of OX-A also may be partly relevant to the regulation of the NPY system in the hilus of the dentate gyrus.     

香烟烟雾暴露对未成年小鼠齿状回神经发生和小胶质细胞的影响

为探讨香烟烟雾暴露(cigarette smoking exposure,CSE)对未成年小鼠的神经发生及学习记忆的影响,本研究用亲和组织化学方法,以5-溴脱氧尿苷(5-bromodeoxyuridine,BrdU)和西非单叶豆同工凝集素-B4(Bandeirae SimplicifoliaIsolectin-B4,BSI-B4)分别标记新生细胞和小胶质细胞(microglia,MG),观察了CSE小鼠齿状回内的神经发生及MG数目的变化,并通过Morris水迷宫训练测验其空间学习能力。结果显示:CSE下小鼠齿状回内的神经发生降低,MG数目显著减少;而在水迷宫的学习中,CSE组的逃避潜伏期亦明显长于对照组(P<0.05)。上述结果表明CSE损害了未成年小鼠齿状回内的神经发生,抑制了MG的激活,同时小鼠的空间学习能力与神经发生及激活的MG数量平行变化。此结果提示CSE造成的学习能力降低可能与齿状回神经发生及MG减少有关。