高压氧治疗创伤性脑损伤的效用及机制研究

目的:研究高压氧(HBO)对大鼠创伤性脑损伤(TBI)治疗效用并观察脑组织星形胶质细胞活化及胶质细胞源性神经营养因子(GDNF)和神经生长因子(NGF)表达的变化以探讨作用机制。方法:SD雄性大鼠54只,随机分为3组(n=18):假手术组、TBI组和HBO治疗组。采用Feeney法建立大鼠TBI模型,假手术组只开放骨窗,不予打击。HBO治疗组大鼠于脑损伤后6 h采用动物高压舱,以3ATA压力纯氧治疗60 min。TBI后48 h测量神经功能,然后分离脑组织,其中18只用干湿法测定脑含水量;18只脑组织用于切片,部分进行尼氏染色后作形态学观察,部分进行免疫组织化学染色,检测星形胶质细胞标记物胶质纤维酸性蛋白(GFAP)、波形蛋白(vimentin)与S100蛋白的表达;另18只大鼠取伤侧脑半球,进行Western blot分析,观察GDNF和NGF的表达。结果:HBO治疗能减轻神经功能障碍,降低脑含水量,减少海马部位神经细胞丢失,进一步激活损伤侧皮质与海马部位GFAP、vimentin与S-100阳性表达星形胶质细胞,促进损伤侧脑组织GDNF与NGF的表达。结论:HBO对创伤性脑损伤有较好治疗效果,其机制与上调GDNF和NGF的表达有关。     

神经上皮干细胞的分离培养及其体外分化特性的观察

目的探讨大鼠胚胎神经管神经上皮干细胞的分离培养条件,并观察其在体外的分化特性.方法采用显微解剖、机械吹打、无血清悬浮培养方法分离培养神经上皮干细胞,采用巢蛋白(nestin)免疫细胞化学染色技术检测神经上皮干细胞,用NSE和GFAP免疫组化染色检测并计数神经细胞和神经胶质细胞.结果大鼠胚胎神经管神经上皮干细胞在无血清培养基中可形成大量呈nestin抗原阳性细胞构成的神经球,经传代有血清培养后分化为NSE阳性和GFAP阳性细胞,其中NSE阳性细胞占细胞总数的47.7%,GFAP阳性细胞占细胞总数的39.8%.结论胎鼠神经管神经上皮干细胞在无血清培养中可增殖和传代,在有血清培养中可分化为神经细胞和神经胶质细胞,两者之比为47.7∶39.8.     

电针对脊髓损伤星形胶质细胞增生及其NGF表达的影响

目的研究脊髓损伤后电针治疗对星形胶质细胞增生及其内源性神经生长因子(nerve growth factor,NGF)表达的影响.方法选用成年雌性Wistar大鼠,随机分为3组.A组为正常对照组,B组、C组为下胸段脊髓不完全损伤.B组损伤后不治疗,C组损伤后给予督脉电针治疗.损伤后3 d、1 、2或4周应用免疫组化染色分别观察损伤脊髓胶质原纤维酸性蛋白(glial fibroblast acid protein,GFAP)和NGF表达的变化.结果 B组术后3 d,GFAP阳性细胞明显增多, 2周后开始减少,4周时仍有较多的阳性细胞;C组GFAP阳性细胞明显少于B组,1周时达高峰.脊髓损伤后NGF表达呈逐渐增加的趋势.C组NGF的表达明显高于B组,且一直保持在较高水平.NGF阳性细胞大部分与GFAP阳性细胞形态相似.结论电针治疗能减少星形胶质细胞增生,促进内源性NGF的合成,从而创造了有利于神经再生的微环境.     

人脑老化过程中胶质纤维酸性蛋白的表达变化

目的:研究人脑老化过程中胶质纤维酸性蛋白(GFAP)的表达变化.方法:两例人脑标本,样本一:女性,64岁,生前诊断有血管性淀粉病变;样本二:男性,16岁,死于急性心肌炎,两例标本均于死后12 h取脑,取皮质和海马部位,进行GFAP的常规免疫组化染色进行定量分析.结果:老年脑星形胶质细胞呈明显激活状态,GFAP阳性细胞数目显著增多,胞体增大,突起粗短,刚果红染色可见老年斑周围GFAP阳性细胞成簇聚集;年轻脑GFAP阳性细胞数目少,胞体瘦小,突起细长,未见GFAP阳性细胞成簇聚集.统计学分析表明GFAP阳性细胞数和蛋白质的表达变化在老年脑和年轻脑具有差别显著性(P＜0.Ol) .结论:衰老和血管淀粉样病变在人脑星形胶质细胞的增生和激活过程中具有重要的作用.     

RCMV感染星形胶质细胞对神经干细胞分化的影响

探讨大鼠巨细胞病毒（rat cytomegalovirus,RCMV）感染大鼠星形胶质细胞后,对神经干细胞分化的影响。原代分离培养新生大鼠星形胶质细胞和胚胎海马神经干细胞,将星形胶质细胞感染RCMV后和神经干细胞在Transwell24孔共培养体系下进行共培养,同时设对照组;用免疫荧光染色等方法检测神经干细胞与感染RCMV的星形胶质细胞共培养后,其分化细胞中神经元微管相关蛋白（microtubule-associated protein 2,MAP2）和星形胶质细胞胶质纤维酸性蛋白（glial fibril—lary acidic protein,GFAP）的表达。结果发现,感染RCMV的星形胶质细胞与神经干细胞共培养时,神经干细胞分化减慢,分化成的神经元和星形胶质细胞比率低于对照组,提示星形胶质细胞感染RCMV后可抑制神经干细胞的分化,可能与RCMV影响星形胶质细胞合成和分泌各种营养因子,干扰了神经干细胞的分化进程有关。     

人胚胎干细胞分化为神经干细胞诱导方法的对比研究

目的探讨人胚胎干细胞分化为神经干细胞过程中,经拟胚体（embryonic body,EB）法和直接分化法的不同效率。方法人胚胎干细胞常规培养消化后,分为两组：A组,经EB法分化;B组,添加noggin和ITSFn直接分化法。倒置相差显微镜观察细胞形态变化,RT-PCR检测细胞各阶段标志物,免疫荧光及流式细胞仪观察两组细胞Nestin阳性细胞率。神经干细胞继续分化,免疫荧光、RT-PCR法检测MAP2、GFAP表达。结果RT-PCR检测到OCT4、nestin表达。B组nestin阳性细胞率明显高于A组,差异有统计学意义（P〈0.01）,且诱导周期短于A组。神经干细胞继续分化,得到不同数量的神经元和胶质细胞,MAP2、GFAP分别阳性。结论在体外采用定向分化诱导,人胚胎干细胞不经EB,可直接定向分化为神经干细胞,且诱导效率比EB法高。因此直接分化法是一种经济实用的诱导方法。     

急性酒精中毒合并中度创伤性脑损伤大鼠海马GFAP的表达

目的:观察急性酒精中毒合并中度创伤性脑损伤后大鼠海马星形胶质细胞标记物胶质纤维酸性蛋白(GFAP)表达的变化.方法:健康成年雄性SD大鼠72只,随即机分为4组:假手术组(N组)、急性酒精中毒组(E组)、中度创伤性脑损伤组(T组)和急性酒精中毒合并中度创伤性脑损伤组(E T组).腹腔注射酒精(2.5g/kg)致使大鼠急性酒精中毒,2h后,按改进的Feeney's自由落体硬膜外撞击方法使其合并中度创伤性脑损伤(600g.cm).各组动物术后6h、24h和48h处死.中性红染色观察海马CA1区神经元形态学改变;用免疫组织化学的方法检测海马CA1区GFAP表达变化.结果:与N组和E组相比,T组和E T组GFAP表达显著增多(P＜0.01).术后6h和24h,T组GFAP表达显著高于E T组(P＜0.05);T组和E T组的海马CA1区神经元细胞出现胞体肿胀,排列散乱,但T组上述形态学改变较E T组明显.结论:急性酒精中毒合并中度创伤性脑损伤的早期可通过减少GFAP的表达,抑制星形胶质细胞激活,减少炎症反应发挥保护作用.     

叶酸联合成体神经干细胞治疗创伤性脑损伤大鼠的实验

目的观察叶酸联合成体神经干细胞对创伤性脑损伤大鼠的治疗作用,探讨其可能作用机制。方法 120只Wistar大鼠随机分为6组,正常组,模型组,假手术组,叶酸注射组,成体神经干细胞移植组,成体神经干细胞移植＋叶酸注射组。倒置显微镜下观察神经干细胞形态学变化;流式细胞仪检测神经干细胞表面标记物CD105、CD45、CD44、CD29的表达;免疫荧光法检测神经元特异性烯醇酶（NSE成熟神经元的特异性标志）、胶质纤维酸性蛋白（GFAP胶质细胞的标记物）的表达;平衡木实验检测大鼠运动协调与整和能力;Morris水迷宫实验测试各组大鼠的学习记忆能力;HE染色及Brdu免疫组化实验观察脑组织形态学变化;酶联免疫吸附试验检测大鼠脑组中脑源性神经生长因子（BDNF）、神经生长因子（NGF）的表达;蛋白质印迹法检测脑组织中凋亡相关蛋白BCL-2、Bax、Caspase-3的表达。结果分离所得细胞能在体外传代培养,流式细胞仪检测发现细胞阳性表达CD44、CD29,阴性表达CD105、CD45,细胞经胎牛血清诱导分化后能形成NSE或GFAP阳性细胞。实验表明,叶酸与成体神经干细胞干预创伤性脑损伤大鼠模型后能显著改善其行为学变化,减轻脑组织的炎症反应,恢复受损神经细胞,增加脑组织内BDNF、NGF的含量,上调BCL-2的表达,下调Bax、Caspase-3的表达。结论叶酸联合成体神经干细胞干预创伤性脑损伤大鼠能显著改善中枢神经功能,对维持神经元微环境稳态具有重要的作用。     

产前应激对子代大鼠脑缺血/再灌注后星形胶质细胞的影响

目的：探讨产前应激对雄性子代大鼠大脑中动脉缺血/再灌注后星形胶质细胞的影响。方法：SD孕鼠随机分为有产前应激处理（妊娠第15到21天每日3次限制活动）和无产前应激处理,并对其雄性子代大鼠采用线栓法制备大脑中动脉闭塞（MCAO）模型,共分为产前应激+假手术组、MCAO模型组、产前应激+MCAO组（n=10）,于再灌注后第5天检测脑梗死体积,免疫荧光双标染色检测缺血灶边缘区星形胶质细胞形态及促红细胞生成素肝细胞受体A4（EphA4）和胶质纤维酸性蛋白（GFAP）的共表达情况,并采用Western blot检测EphA4、GFAP和神经蛋白聚糖（Neurocan）蛋白表达。结果：产前应激+MCAO组子代大鼠脑梗死体积百分比、EphA4、GFAP和Neurocan蛋白表达均较MCAO组显著增加（P均<0.05）,且GFAP阳性细胞形态学改变及EphA4/GFAP共表达也较MCAO组明显。结论：产前应激可能改变子代大鼠脑缺血/再灌注后星形胶质细胞上EphA4受体的表达,促进星形胶质细胞活化,产生神经蛋白聚糖。     

Nogo—p4与NgR结合抑制神经干细胞分化为双极形星形胶质细胞的突起生长

目的观察Nogo—p4是否通过与NgR结合的途径对大鼠脊髓来源神经干细胞分化形成双极形星形胶质细胞突起长度产生抑制。方法取4只出生24h内的Wistar大鼠,悬浮培养法培养大鼠脊髓来源的神经干细胞。把神经干细胞分为A、B、C、D四组,A组加入血清,B组加入血清和Nogo—p4,C组神经干细胞经RNA干扰沉默NgR基因后加入血清分化,D组神经干细胞经RNA干扰沉默NgR基因后加入血清和Nogo—p4。分化第7d,GFAP抗体标记星形胶质细胞,使用Image—ProPlus5．0软件测量双极形星形胶质细胞突起长度。结果神经干细胞分化第7d,四组均可形成双极形星形胶质细胞。B组中双极形星形胶质细胞的突起长度明显短于其它各组。A、C、D组中双极形星形胶质细胞的突起长度没有显著差异。结论Nogo—p4经与NgR结合途径显著抑制脊髓来源神经干细胞分化成的双极形星形胶质细胞的突起生长。     

Fimbria–fornix (FF)-transected hippocampal extracts induce the activation of astrocytes in vitro

Hippocampus is one of the neurogenesis areas in adult mammals, but the function of astrocytes in this area is still less known. In our previous study, the fimbria–fornix (FF)-transected hippocampal extracts promoted the proliferation and neuronal differentiation of radial glial cells in vitro. To explore the effects of hippocampal extracts on gliogenesis, the hippocampal astrocytes were treated by normal or ff-transected hippocampal extracts in vitro. The cells were immunostained by brain lipid-binding protein (BLBP), nestin, and SOX2 to assess their state of activation. The effects of astrocyte-conditioned medium on the neuronal differentiation of hippocampal neural stem cells (NSCs) were also investigated. After treatment of FF-transected hippocampal extracts, the number of BLBP, nestin, and Sox-positive cells were obviously more than the cells which treated by normal hippocampal extracts, these cells maintained a state of activation and the activated astrocyte-conditioned medium also promoted the differentiation of NSCs into more neurons. These findings suggest that the astrocytes can be activated by FF-transected hippocampal extracts and these activated cells also can promote the neuronal differentiation of hippocampal NSCs in vitro.     

HBO治疗对急性CO中毒后海马不同分区神经细胞凋亡的作用研究

目的:通过研究高压氧(HBO)治疗急性CO中毒大鼠海马不同分区神经细胞凋亡情况,探讨HBO治疗急性CO中毒的应用及机理。方法:利用雄性SD大鼠,建立急性CO中毒模型。应用免疫组织化学以及免疫荧光的方法,测定在染毒和CO中毒HBO治疗后1 d、3 d、7 d、14 d和21d Bcl-2、caspase-3、Neu N、BAX和MMP-9的表达水平的变化。结果:海马CA3区神经细胞对急性CO中毒与HBO治疗比CA1和CA2区更加敏感;急性CO中毒后,海马各区神经细胞凋亡程度随1 d、3 d、7 d、14 d和21 d时间延长而加重;BAX、caspase-3和Bcl-2等凋亡相关因子的表达水平与MMP-9的变化趋势一致:在1d开始增多,3d达到最大值,7d开始减少,14 d与21 d与正常组类似;CO中毒大鼠进行HBO治疗后,海马各区MMP-9、BAX、caspase-3和Bcl-2的表达水平明显降低;且HBO治疗7 d后,海马各区这些凋亡相关因子的表达降低最为明显。结论:海马CA3区神经细胞对急性CO中毒及HBO治疗敏感;海马神经细胞凋亡可能与神经细胞表达MMP-9降解神经细胞周围的基质,表达BAX、caspase-3和Bcl-2等凋亡相关因子促进凋亡发生有关;HBO治疗可降低MMP-9以及BAX、caspase-3和Bcl-2等凋亡因子的表达,抑制神经细胞的凋亡;HBO治疗7d对神经细胞凋亡的抑制作用最明显。     

Neural stem cells transplanted into intact brains as neurospheres form solid grafts composed of neurons, astrocytes and oligodendrocyte precursors

Neural stem cells (NSCs) are tissue-specific stem cells with self-renewal potential that can give rise to neurons and glia in vivo and in vitro. The aim of this study was to transplant NSCs as whole neurospheres into intact brain and assess the fate and phenotype of their progeny generated in vivo. We isolated NSCs from E14 foetal rat forebrains and cultured them in basic fibroblast and epidermal growth factor-supplemented serum-free medium in the form of neurospheres in vitro. Neurospheres were transplanted into the intact brains of 2 Wistar rats and after a period of 3 weeks, grafted brains were examined immunohistochemically. Neurospheres formed solid grafts that were found in the lateral ventricle and in the velum interpositum under the hippocampus. The majority of cells in the transplanted tissue were identified as beta-III-tubulin(+), NeuN(+), PanNF(+) and synaptophysin(+) neurons and were accumulated throughout the graft centre. GFAP(+) astrocytes were scattered throughout the entire graft and astrocyte processes delimited the outer and perivascular surfaces. A great number of NG2(+) oligodendrocyte precursors was detected. Nestin(+) endothelial cells were found to line capillaries growing in the transplant. These data indicate that nestin(+) NSCs prevailing in neurospheres differentiate following transplantation into nestin(-) neuronal and glial cells which confirms the multipotency of NSCs. Three weeks posttransplantation neuronal and astrocyte cells reached terminal differentiation (formation of synaptic vesicles and superficial and perivascular limiting membranes) while elements of oligodendroglial cell lineage remained immature. Grafting stem cells as non-dissociated neurospheres provide cells with favourable conditions which facilitate cell survival, proliferation and differentiation. However, in the intact brain, grafted neurosphere cells were not found to integrate with the brain parenchyma and formed a compact structure demarcated from its surroundings.     

Lentivirus-mediated microRNA-26a-modified neural stem cells improve brain injury in rats with cerebral palsy

This study is launched to investigate the effect of lentivirus-mediated microRNA-26a (miR-26a)-modified neural stem cells (NSCs) in brain injury in rats with cerebral palsy (CP). The successfully constructed miR-26a lentivirus expression vector and empty vector virus were used to modify NSCs. The model of CP with ischemia and anoxia was established in rats. NSCs and miR-26a-NSCs were stereoscopically injected into the cerebral cortex of the modeled rats, respectively. The survival and migration of NSCs infected with recombinant lentivirus expressing green fluorescence in vivo was observed under a light microscope. The neurobehavioral functions, morphology, and ultrastructure of cerebral cortex and hippocampus, apoptosis of brain cells, expression of apoptosis-related protein caspase-3 and Bax, together with the expression of the glial fibrillary acidic protein (GFAP) in cerebral cortex and hippocampus were determined. Expression of miR-26a in NSCs infected with plVTHM-miR-26a increased significantly. After NSCs transplantation, the neurobehavioral status of CP rats was improved, the degree of brain pathological injury was alleviated, the apoptotic index of cells in cerebral cortex and hippocampus and the expression of the apoptotic protein (caspase-3 and Bax) were decreased, the expression of GFAP were significantly decreased. After miR-26a-NSCs transplantation, these aforementioned results further improved or decreased. Our study suggests that miR-26a-modified NSCs mediated by lentivirus can improve brain injury, inhibit apoptosis of brain cells and activation of astrocytes in CP rats.     

NDRG2与GFAP在不同脑区星形胶质细胞的表达与分布

目的:观察NDRG2(N-myc下游调节基因2)与GFAP(胶质纤维酸性蛋白)在不同脑区星形胶质细胞的表达与分布。方法:利用免疫荧光NDRG2与GFAP双标技术以及Western Blot技术观察皮层、海马及纹状体等不同脑区星形胶质细胞NDRG2和GFAP的表达与分布。结果:免疫荧光结果显示NDRG2阳性细胞广泛而均匀地分布于不同脑区,并与GFAP存在较好的共定位;NDRG2与GFAP标记的星形胶质细胞形态不尽相同。Western Blot结果显示NDRG2在皮层中表达比海马和纹状体多,而GFAP在海马中表达比皮层和纹状体多。结论:NDRG2广泛表达于不同脑区星形胶质细胞,并于GFAP存在较好的共定位。