骨形成蛋白2在神经干细胞诱导分化中的作用

神经干细胞的多向分化潜能 ,使其成为替代治疗的内源性和外源性潜在细胞源 ,为治疗神经系统退行性疾病和中枢神经系统损伤带来了希望。神经干细胞的定向诱导分化 ,是当前神经干细胞研究领域的难点和热点。生长因子TGF beta超家族成员BMP2在骨发育形成中的重要作用已为许多研究所证实。近年来国内外对BMP2在神经系统发育中的作用进行了广泛研究 ,证实BMP2在诱导神经干细胞分化中发挥重要的作用 ,表现为一种多效性神经诱导因子。本文对近年来国际上关于BMP2诱导神经干细胞分化的研究做一综述     

脂肪干细胞经低浓度骨形成蛋白2或骨形成蛋白7短期诱导后软骨及骨基因的表达

目的：探讨脂肪干细胞经低浓度骨形成蛋白2、骨形成蛋白7短期诱导后向软骨细胞和骨细胞方向的分化情况。 方法：无菌切取成年新西兰大白兔皮下脂肪,胶原酶消化法体外分离培养脂肪干细胞,分为3组：骨形成蛋白2组加入含0.1 g/L维生素C、10 mmol/L β-甘油磷酸钠、10 μg/L骨形成蛋白2的诱导培养基培育15 min,然后按18×104个细胞/孔接种,再培育4~14 d;骨形成蛋白7组培养方法基本相同,仅将骨形成蛋白2更换为骨形成蛋白7;对照组同法加入单纯培养基进行培育。 结果：与对照组比较,骨形成蛋白2组、骨形成蛋白7组可上调脂肪干细胞数达1.78~1.79倍,上调蛋白含量达1.15~1.95倍,上调碱性磷酸酶活性达32~40倍。与对照组比较,诱导15 min培育4 d时,骨形成蛋白2组runx-2基因表达提高1.9倍,骨桥素基因表达提高2.2倍,双聚糖基因表达提高1.3~1.7倍;骨形成蛋白7组仅双聚糖基因表达提高1.3~1.7倍,不影响runx-2、骨桥素基因的表达。与对照组比较,诱导15 min培育14 d时,骨形成蛋白2组runx-2、骨桥素、双聚糖及aggrecan基因表达无变化;骨形成蛋白7组runx-2基因表达下调1.8倍,骨桥素基因表达下调5.0倍,双聚糖基因表达下调1.7倍,aggrecan基因表达有所提高。 结论：经短期诱导后,再培养4 d骨形成蛋白2刺激runx-2和成骨基因的表达,14 d时骨形成蛋白7下调这些基因的表达,却上调蛋白多糖聚合体基因的表达。     

戊四氮点燃癫(癎)大鼠海马巢蛋白和骨形成蛋白-4的表达研究

目的观察巢蛋白(nestin)和骨形成蛋白4(BMP4)基因在戊四氮(PTZ)点燃癫大鼠海马中的表达,并探讨两者与癫发病机制的关系。方法将81只成年雄性SD大鼠随机分为实验组(n=54)和对照组(n=27)。实验组采用PTZ点燃癫大鼠,按点燃中的不同时相点,又随机分为9组。用免疫组化技术、地高辛标记特异性寡核苷酸探针原位杂交组织化学技术,观察海马nestin和BMP4表达的变化。结果nestin阳性细胞在PTZ注射后3d开始出现在齿状回、CA3区和CA1区,到7d达到高峰,以后逐渐减少。BMP4在PTZ注射后7d开始增多,在点燃后1d达到高峰,以后逐渐减少,主要分布在齿状回、CA3区和CA1区。结论PTZ点燃可引起海马内星形胶质细胞增生、活化和神经发生,这可能是癫海马组织胶质化、神经元可塑性的病理基础;BMP4可能在PTZ癫形成过程中起重要作用。     

室管膜前下区神经干细胞向神经元分化中骨形成蛋白2及DLX5的作用*

背景：目前神经干细胞应用的最大障碍还在于分化的调控,而对干细胞分化调控机制尚知之甚少。室管膜前下区是目前公认的神经干细胞富集区之一。在此区的神经干细胞可以长距离迁移到嗅球而保持神经干细胞不分化,最后在嗅球分化为中间神经元。骨形成蛋白2及DLX5在室管膜前下区神经干细胞向嗅球迁移分化过程中起着重要作用。目的：研究室管膜前下区神经干细胞的构筑及迁移特点,以及目前国内外有关骨形成蛋白2及DLX5在此区神经干细胞迁移分化中的作用,希望对神经干细胞的分化调控机制有一定的认识。方法：由第一作者利用中文检索词“神经干细胞,室管膜前下区,骨形成蛋白2,DLX5”及英文检索词“neural stem cells,SVZa,BMP-2,DLX5”,在PubMed数据库(http://www.ncbi.nlm.nih.gov/PubMed)、中国期刊全文数据库(www.cnki.net/index.htm)、万方数据库(http://www.wanfangdata.com.cn)中检索1997-01/2009-01关于骨形成蛋白2、DLX5在室管膜前下区神经干细胞向神经元分化中作用的文献。排除内容陈旧或重复文献。结果与结论：初检得到121篇文献,中文86篇,英文35篇。最后对符合标准的28篇文献作进一步的分析。结果提示,室管膜前下区神经干细胞具有其独特细胞构筑和长距离迁移的特点,骨形成蛋白2及DLX5在其迁移分化过程中起着重要作用,但其具体作用机制仍不清楚。     

喹硫平对脂多糖损伤后海马神经干细胞的保护作用

目的：探讨喹硫平（QUE）对脂多糖（LPS）损伤后海马神经干细胞（NSCs）活性的作用及增殖情况的影响,并初步研究胞外信号调节激酶（ERK ）信号通路在其中的作用。方法建立体外大鼠海马NSCs的LPS损伤细胞模型,分为对照组（Sham组）、LPS组、LPS＋ QUE组（包括0．5μmol／L、1μmol／L和2μmol／L三个不同剂量组）,作用48 h后,采用WST －8试剂检测细胞活性,蛋白质印迹（Western Blot）法检测磷酸化胞外信号调节激酶1／2（pERK1／2）的表达水平,5－溴脱氧尿嘧啶核苷（BrdU ）检测细胞增殖情况。并在培养基中添加ERK磷酸化抑制剂U0126,以进一步明确ERK信号通路在其中的作用。结果（1）细胞活力：与Sham组[吸光度值（0．371±0．027）]相比,LPS组（0．251±0．034）细胞活力显著下降（P ＜0．01）,而 LPS＋ QUE 1μmol／L 组（0．311±0．018）和 LPS＋ QUE 2μmol／L组（0．343±0．021）均显著抑制了LPS对其活力的影响（与LPS组相比,P＜0．05）。（2）West‐ern Blot结果显示,LPS组的pERK1／2表达水平（0．313±0．124）明显低于Sham组（1．417±0．141）及LPS＋QUE 1μmol／L组（0．681±0．098）组和LPS＋QUE 2μmol／L组（0．954±0．119）（P＜0．05）,而LPS组与LPS＋QUE 0．5μmol／L组（0．368±0．123）的pERK1／2表达水平接近。（3）BrdU 染色结果显示,LPS组的BrdU阳性细胞数百分比（23．098±2．153）％明显低于Sham组（40．388±2．910）％, LPS＋QUE 1μmol／L 组（28．742±1．536）％和 LPS＋ QUE 2μmol／L 组（31．369±2．313）％（P ＜0.05）。（4）U0126可抑制QUE（1μmol／L和2μmol／L）的上述作用。结论 QUE能抑制LPS导致的NSCs损伤,这种作用与调节ERK1／2的磷酸化有关。     

海马神经干细胞不同传代方法的比较

背景：体外培养神经干细胞,在悬浮培养时由于自身增殖特性会形成球,传代时将会面临如何将细胞球分离成单细胞的问题。 目的：寻求理想的大鼠海马神经干细胞传代方法,以获得大量可增生的神经干细胞以供研究。 方法：分离新生1 d SD大鼠海马神经干细胞,原代培养至五六天时,分别用机械吹打法、胰蛋白酶、TrypLE和Accutase消化法分离神经干细胞球。之后每7 d传代1次,连续传代3次。分别于每次传代后第1天和传代后第4天计数活细胞比例和细胞球数目,实验重复3次。 结果与结论：神经干细胞球经3种酶消化后获得的均是单细胞;经机械吹打后既有单个细胞,也有小细胞球分布于培养液中。在酶消化法中,Accutase消化法传代后神经干细胞的活细胞比例明显高于胰蛋白酶消化(P < 0.01)和TrypLE消化法 (P < 0.05)。同时,Accutase消化法传代后新形成的细胞球数目也较其余各组多(P < 0.01)。提示在实验条件下,Accutase消化法能够较好地将神经干细胞球分离成存活率较高、能快速形成新的克隆球的单个细胞,是较为理想的神经干细胞分离传代方法。     

Noggin参与海人酸损伤后成年大鼠海马颗粒下区颗粒细胞增殖

目的 探讨侧脑室注射海人酸(KA)致大鼠海马损伤后Noggin的表达变化及其与颗粒细胞增殖的关系.方法 健康雄性SD大鼠32只采用随机数字表法分为实验组(16只)及对照组(16只).对照组又分为生理盐水对照组和空白对照组,各8只.实验组大鼠侧脑室注射KA,生理盐水对照组注射等剂量生理盐水.空白对照组不作处理.侧脑室注射KA 1周内,尼氏染色检测海马神经元的丢失.免疫荧光染色与原位杂交的方法检测海马齿状回BrdU标记细胞与Noggin mRNA阳性细胞的变化.结果 在侧脑室注射KA致海马损伤后1周,海马CA3、CA4区神经元丢失明显.与生理盐水对照组比较,实验组海马齿状回BrdU阳性细胞升高,差异有统计学意义(P=0.006),其中注射侧较对侧更为明显.海马Noggin mRNA阳性细胞在第3天时升高,第7天时下降.结论 侧脑室注射KA致海马损伤后.成年大鼠海马齿状回颗粒细胞异常增殖可能与Noggin表达波动有关.     

海人酸颞叶癫痫大鼠海马组织中细胞骨架蛋白的差异表达

目的 研究海人酸颞叶癫痫大鼠海马组织中差异表达的细胞骨架蛋白,为阐明癫痫的发病机制提供线索,为新型抗癫痫药物的研发提供分子靶点.方法 利用双向荧光差异凝胶电泳(2D-DIGE)、DeCyder分析软件、基质辅助激光解吸附电离串联飞行时间质谱(MALDI-TOF/TOF-MS)对海人酸诱导颞叶癫痫大鼠海马组织中的差异蛋白进行分离、分析及鉴定.结果 有5个差异蛋白点被鉴定为3种细胞骨架蛋白,其中微管蛋白α-1B和胶质纤维酸性蛋白表达上调,埃兹蛋白表达下调.结论 细胞骨架蛋白表达变化导致的细胞骨架受损可能与癫痫的发生发展相关,可能成为抗癫痫治疗新靶点.     

脑创伤后NGF对神经干细胞Nestin蛋白表达的影响

目的　研究脑创伤后外源性神经生长因子 (NGF)对神经干细胞Nestin蛋白表达的影响及其意义。方法　建立大鼠流体脑创伤模型 ,采用免疫细胞化学及图像分析等方法 ,观察脑创伤后非NGF处理组和NGF处理组Nestin蛋白表达的变化。结果　成年大鼠Nestin阳性细胞主要位于室管膜下组织 ,细胞的形态主要是胶质细胞。脑创伤后Nestin阳性细胞在室管膜下反应性增加 ,以伤后 7d明显 ,同时在创伤区域周围也可见到大量的Nestin阳性细胞 ,并在伤后 14d继续维持其反应性增加。NGF处理组伤后 7dNestin阳性细胞在伤灶周围更加明显 ,为 2 8.7± 3.8,比同时相点的非NGF处理组明显增加 (P <0 .0 1)。结论　外源性NGF能明显促进脑创伤后Nestin阳性细胞数量的增加 ,增强星形胶质细胞对脑创伤的反应并使其表现有神经干细胞的特征 ,参与神经细胞的再生和重塑。     

孕期脉冲电磁场与子代大鼠海马神经干细胞增殖及巢蛋白的表达

背景：电磁场能对机体产生影响,尤其对于神经系统。研究已发现了脉冲电磁场对神经干细胞的影响。 目的：观察产前脉冲电磁场对子代大鼠海马神经干细胞增殖及巢蛋白表达的影响。 方法：选用体质量240~260 g SD雌性大鼠为母鼠,随机分为2组。对照组孕期不给任何干预;产前脉冲电磁场组于怀孕14~20 d,给予脉冲电磁场刺激,3次/d,10 min/次。于雌、雄仔鼠1月龄时每组随机各组6只行脑组织切片,应用免疫组织化学方法检测海马中Nestin蛋白和Brdu阳性细胞的表达。 结果与结论：产前脉冲电磁场组雌雄子代海马Nestin蛋白和Brdu阳性细胞表达均较对照组多(P < 0.001),,且产前脉冲电磁场组雌性子代海马Nestin蛋白和Brdu阳性细胞表达较雄性子代的多,差异具有非常显著性意义(P < 0.001),对照组雌雄子代之间差异无显著性意义(P > 0.05)。结果表明,产前脉冲磁场能引起子代海马神经干细胞数增多及增殖能力增加,这可能是机体对产前脉冲电磁场所致脑损伤的代偿性反应。     

骨形态发生蛋白4体内外诱导脑神经干细胞向胆碱能细胞的分化

目的：了解骨形态发生蛋白－4 (BMP4) 是否具有诱导原代分离培养的大鼠脑神经干细胞（NSCs）向胆碱能细胞分化的效应。方法：将从两月龄大鼠脑海马、纹状体等区域分离的细胞培养于含EGF、bFGF的DMEM/F12培养液中,在光镜下观察细胞的形态特征,并行Nestin细胞化学染色。24h后换成含有BMP4的培养液,培养7d、8d时,行胆碱乙酰转移酶（choline acetyltransferase, ChAT）和神经巢蛋白Nestin双标免疫细胞化学染色及ChAT间接免疫荧光染色,在光镜下观察细胞形态的变化。结果：分离出的大鼠脑海马、纹状体等区的细胞约48%为nestin阳性的NSCs。培养7d、8d时,光镜下见加BMP4组约34%的细胞呈神经元形态特征;免疫双标细胞化学染色见ChAT阳性细胞与Nestin阳性细胞共存,其中ChAT阳性细胞占28%,Nestin阳性细胞占38%;间接免疫荧光染色见呈较强绿色荧光的ChAT阳性细胞较多;FITC标记流式细胞术检测到16％的细胞呈ChAT阳性。而未加BMP4组呈ChAT阳性的细胞约7％,明显少于加BMP4组,且荧光较弱。结论：BMP4可在体外培养条件下诱导大鼠脑神经干细胞向胆碱能细胞分化。     

Gastrodin blocks neural stem cell differentiation into glial cells mediated by kainic acid

Kainic acid can simulate excitatory amino acids in vitro.Neural stem cells,isolated from newborn Wistar rats,were cultured in vitro and exposed to 100-4 000 μM kainic acid for 7 days to induce neuronal cell differentiation,causing the number of astrocytes to be significantly increased.Treatment with a combination of 0.5 mg/L gastrodin and kainic acid also caused the number of differentiated neurons to be significantly increased compared with treatment with kainic acid alone.Experimental findings suggest that gastrodin reduces the excitability of kainic acid and induces neural stem cell differentiation into neurons.     

骨髓源性神经干细胞自体移植对癫(癎)大鼠海马的修复作用

目的 探讨骨髓源性神经干细胞自体移植对癫(癎)大鼠海马的修复作用.方法 雄性SD大鼠随机分为正常对照组、移植组和非移植组.无菌条件下分离大鼠骨髓基质细胞,在特定条件下培养、诱导其分化为神经干细胞;对移植组和非移植组大鼠建立颞叶癫(癎)模型,将诱导分化的神经干细胞自体移植至移植组大鼠右侧海马内,观察移植后1周、2周、4周、8周和16周模型鼠海马的形态学变化.结果 移植组与非移植组海马CA3区锥体细胞数各时间点显著少于正常对照组(均P＜0.01);与非移植组比较,移植组海马CA3区锥体细胞数于移植后第2～16周明显增多(均P＜0.01);移植组各时间段之间差异有统计学意义(均P＜0.01).与正常对照组相比,移植组和非移植组海马损伤侧的Timm染色评分显著增高(均P＜0.01);但移植组移植2周后各时间点评分显著低于非移植组(均P＜0.01);非移植组随制模时间延长评分持续升高.MRI检查显示在神经干细胞移植后1周和2周时低信号改变区比较局限,此后低信号影随着时间的推移逐渐增大.结论 骨髓源性神经干细胞自体移植至癫(癎)大鼠后能够在海马中生存并迁移,具有减轻海马CA3区锥体细胞缺失、抑制海人酸引起的苔状纤维发芽的修复作用.     

Survival of grafted fetal neural cells in kainic acid lesioned CA3 region of adult hippocampus depends upon cell specificity

We hypothesize that the degree of graft cell survival within the damaged CNS correlates with the specificity of donor cells to the region of grafting. We investigated graft cell survival following transplantation of fetal micrografts into the CA3 region of the adult rat hippocampus at a time-point of 4 days after an intracerebroventricular administration of kainic acid (KA). Grafts consisted of 5'-bromodeoxyuridine (BrdU) labeled embryonic day (E) 19 cells from hippocampal fields CA3 and CA1 and E15 and E19 cells from the striatum. Absolute cell survival in these grafts was quantitatively analyzed at 1 month postgrafting, using BrdU immunostaining of serial sections and three-dimensional reconstruction of grafts. Absolute graft cell survival in lesioned CA3 was dramatically greater for cells having hippocampal origin (CA3 cells, 69% cell survival; CA1 cells, 42% cell survival) than those having nonhippocampal origin, such as striatal cells (E15 cells, 12% cell survival; E19 cells, 4% cell survival). This difference is in sharp contrast to survival of these cells in culture, where E19 cells from both hippocampal and nonhippocampal origins exhibited similar survival. Comparison of survival among hippocampal cell types indicated significantly greater survival for cells that are specific to the lesioned area (i.e., CA3 cells) than for those that are nonspecific to the lesioned area (i.e., CA1 cells). Graft cell survival in the intact CA3 region (contralateral to KA administration), however, did not differ either between cells having hippocampal and nonhippocampal origins or between CA3 and CA1 cells (CA3 cells, 26% cell survival; CA1 cells, 33% cell survival; and E15 striatal cells, 20% cell survival). These results underscore the finding that enhanced survival of fetal cell grafts in the lesioned CNS is critically dependent upon the specificity of donor fetal cells to the region of transplantation. Thus, grafting of cells that are specific to the lesioned area is a prerequisite for achieving maximal graft cell survival and integration in the lesioned host CNS.     

红藻氨酸致痫大鼠海马Fos和GFAP的共同表达

目的 研究红藻氨酸（kainic acid,KA)诱导大鼠癫痫发作后海马（hippocampus,HI)内神经元和星形胶质细胞的时空效应性反应变化。方法 大鼠侧脑室内注射KA，用抗即刻早期基因Fos蛋白和抗胶质原纤维酸性蛋白（GFAP）的双重免疫荧光组织化学方法结合激光共聚焦显微镜技术，显示痫性发作后HI同一部位内反应性神经元与星形胶质细胞的分布。结果 KA诱导大鼠癫痫发作，HI内的Fos阳性神经元和GFAP阳性星形胶质细胞明显增多。两分布范围基本一致，且癫痫诱发30min后GFAP开始增多，1h达高峰；1h后Fos阳性产物开始增多；2h达高峰；部分Fos阳性神经元周围有GFAP免疫反应产物包绕，显示反应性神经元（Fos阳性）与反应性星形胶质细胞（GFAP阳性）之间关系密切。结论 HI内的神经元和星形胶质细胞与癫痫发作直接相关且存在相互关系。可能共同参与癫痫的发生及其调节。     

抑制自分泌或旁分泌骨形成蛋白和血小板源性生长因子信号可实现大鼠神经干细胞的长期增殖

Continuous expansion of rat neural stem cell lines has not been achieved due to proliferation arrest and spontaneous differentiation in vitro. In the current study, neural precursor cells derived from the subventricular zone of adult rats spontaneously underwent astroglial and oligodendroglial differentiation after limited propagation. This differentiation was largely induced by autocrine or paracrine bone morphogenetic protein and platelet derived growth factor signals. The results showed that, by inhibiting bone morphogenetic protein and platelet derived growth factor signals, adult rat neural precursor cells could be extensively cultured in vitro as tripotent stem cell lines. In addition to adult rat neural stem cells, we found that bone morphogenetic protein antagonists can promote the proliferation of human neural stem cells. Therefore, the present findings illustrated the role of autocrine or paracrine bone morphogenetic protein and platelet derived growth factor signaling in determining neural stem cell self-renewal and differentiation. By antagonizing both signals, the long-term propagation of rat neural stem cell lines can be achieved.     

Behavior of hippocampal stem/progenitor cells following grafting into the injured aged hippocampus

Multipotent neural stem/progenitor cells (NSCs) from the embryonic hippocampus are potentially useful as donor cells to repopulate the degenerated regions of the aged hippocampus after stroke, epilepsy, or Alzheimer's disease. However, the efficacy of the NSC grafting strategy for repairing the injured aged hippocampus is unknown. To address this issue, we expanded FGF-2-responsive NSCs from the hippocampus of embryonic day 14 green fluorescent protein-expressing transgenic mice as neurospheres in vitro and grafted them into the hippocampus of 24-month-old F344 rats 4 days after CA3 region injury. Engraftment, migration, and neuronal/glial differentiation of cells derived from NSCs were analyzed 1 month after grafting. Differentiation of neurospheres in culture dishes or after placement on organotypic hippocampal slice cultures demonstrated that these cells had the ability to generate considerable numbers of neurons, astrocytes, and oligodendrocytes. Following grafting into the injured aged hippocampus, cells derived from neurospheres survived and dispersed, but exhibited no directed migration into degenerated or intact hippocampal cell layers. Phenotypic analyses of graft-derived cells revealed neuronal differentiation in 3%-5% of cells, astrocytic differentiation in 28% of cells, and oligodendrocytic differentiation in 6%-10% cells. The results demonstrate for the first time that NSCs derived from the fetal hippocampus survive and give rise to all three CNS phenotypes following transplantation into the injured aged hippocampus. However, grafted NSCs do not exhibit directed migration into lesioned areas or widespread neuronal differentiation, suggesting that direct grafting of primitive NSCs is not adequate for repair of the injured aged brain without priming the microenvironment.     

Post-ischemic and kainic acid-induced c-fos protein expression in the rat hippocampus

The c-fos protein is a gene regulatory third messenger involved in long-term responses of cells to various stimuli. It can be used as a marker of neuronal activity. In the present immunohistochemical study the presence of c-fos protein (FP) in the rat brain from 1 h to 14 days after 10 min of cerebral ischemia was compared with that 3 h after an intraventricular injection of kainic acid. The kainic acid injection resulted in staining of dentate hilar cells, granule cells and hippocampal interneurones. The postischemic changes at Day 1 were sporadic CA1 pyramidal cells expressing the FP. At Day 2 FP was expressed with variable intensity in many pyramidal cells in the CA1. At Day 3 many necrotic CA1 pyramidal cells were seen. They did not express the FP, and the expression was less intense and found in fewer cells than at Day 2. At Days 3, 7 and 14 there was increasing gliosis without c-fos expression in the CA1. The study demonstrates a delayed postischemic synthesis of the gene regulatory protein c-fos preceding the necrosis in the selectively vulnerable CA1 region.     

Effects of bone morphogenetic protein-4 on spatial memory and cholinergic expression in the dentate gyrus after fornix-fimbria transection in rats

BACKGROUND: Previous experiments have confirmed bone morphogenetic proteins (BMPs) upregulate cholinergic expression in neurons isolated from the embryonic rat hippocampus and cerebral cortex. Therefore, BMPs could be useful for treating Alzheimer's disease and other neurodegenerative diseases. OBJECTIVE: BMP-4 was infused into the hippocampal dentate gyrus of fornix-fimbria transected rats to test the effects of BMP-4 on cholinergic expression in dentate gyrus neurons, and to observe changes in spatial memory behavior. DESIGN: A randomized controlled animal experiment. SETTING: Department of Neurosurgery and Laboratory for Cell Biology, Institute of Geriatrics, General Hospital of Chinese PLA.MATERIALS: Twenty-seven healthy adult male Sprague Dawley (SD) rats, weighing 250-300 g, were provided by the Laboratory Animal Center of the General Hospital of Chinese PLA. Reagents: BMP-4 (B-2680, Sigma Company) and choline acetyl transferase (ChAT) antibody (AB5042, Chemicon Company) were used in this study. Equipments: a rat stereotaxic instrument (type: SN-2N, Narushige Group, Japan) and Image-prog-plus image analysis software (Media Cybernetics company, USA) were used in this study. The protocol was carried out in accordance with ethical guidelines for the use and care of animals.METHODS: This experiment was performed in the Institute of Geriatrics, General Hospital of Chinese PLA between July 2004 and March 2005. Rats were randomly divided into 4 groups: Alzheimer's disease group (n = 7), normal control group (n = 5), BMP-4-Alzheimer's disease group (n = 8), and model group (n = 7). In the Alzheimer's disease group, the left hippocampal fornix-fimbria of rats was transected to mimic Alzheimer's disease symptoms. In the BMP-4-Alzheimer's disease group, 1 μL BMP-4 (10 mg/L) was perfused into the left dentate gyrus with a microinjector at 1 μL/min. In the model group, 1 μL saline was perfused into the same position by the same method. Twenty-eight days after injection, Morris water maze test was performed in all rats to test spatial memory. Time-to-platform and swim-path length were recorded. Immunohistochemical staining of cholinergic neurons was performed on brain sections containing dentate gyrus. The area covered by ChAT-positive cells was analyzed using an Image-prog-plus image analysis software. MAIN OUTCOME MEASURES: Area covered by ChAT-positive cells in the dentate gyrus. Time-to-platform and swim path-length.RESULTS: Twenty-seven rats were included in the final analysis. In the Alzheimer's disease group, the area covered by ChAT-positive cells was significantly smaller compared with the normal control group (F = 76.03, P < 0.01). The area covered by ChAT-positive cells was significantly larger in the BMP-4- Alzheimer's disease group than in the model group (F = 35.17, P < 0.05), but significantly smaller than in the normal control group (F = 40.17, P < 0.05). Time-to-platform and swim-path length were significantly longer in the Alzheimer's disease group than in the normal control group (F =24.62 and 631.58, respectively, both P < 0.05). Time-to-platform and swim-path length were significantly shorter in the BMP4-Alzheimer's disease group compared with the model group (F = 22.06 and 606.89, respectively P < 0.05).CONCLUSION: Injection of BMP-4 into the dentate gyrus of Alzheimer's disease model rats alleviates central cholinergic system injury and concomitantly improves spatial memory.