新生小鼠端脑组织神经干细胞诱导分化为胆碱能神经元的研究

目的探讨新生小鼠端脑组织神经干细胞是否能够分化成胆碱能神经元。方法取新生小鼠端脑组织．用无血清方法分离培养神经干细胞；用克隆培养的方法检验培养细胞的干细胞特性；用免疫荧光细胞化学的方法检测神经干细胞标志巢蛋白（nestin）及干细胞诱导分化后神经元标志微管相关蛋白2（MAP2）、星形胶质细胞标志胶质纤维酸性蛋白（GFAP）、胆碱能标志胆碱乙酰转移酶（CHAT）；比较不同的诱导分化条件（5％胎牛血清、5％胎牛血清＋碱性成纤维细胞生长因子）对胆碱能神经元分化的影响。结果从新生小鼠端脑组织分离培养出具有自我更新、扩增能力的神经球；各培养基中神经球均为nestin阳性。诱导分化后均能够产生MAP2阳性神经元、GFAP阳性星形胶质细胞以及ChAT阳性的胆碱能神经元。分化培养中加入碱性成纤维细胞生长因子能够提高胆碱能神经元分化的比例。结论新生小鼠端脑组织神经干细胞能够分化成胆碱能神经元。     

神经干细胞的端粒酶活性与其增殖分化的关系

目的探讨体外培养的神经干细胞端粒酶活性与细胞增殖、分化的关系,以及细胞分化后端粒酶逆转录酶的表达情况。方法采用无血清培养法从新生大鼠脑皮质分离培养神经干细胞；通过免疫荧光细胞染色鉴定神经干细胞；细胞计数法检测细胞的增殖情况；TRAP-ELISA法测定神经干细胞的端粒酶活性：RT-PCR法和Western-blot法测定细胞分化前后的端粒酶逆转录酶的表达。结果从新生大鼠脑皮质分离培养的神经干细胞具有端粒酶活性；体外培养12周内,神经干细胞的端粒酶活性未见变化,细胞的增殖速率亦未见明显不同；神经干细胞分化后端粒酶活性丧失,端粒酶逆转录酶的mRNA和蛋白质也均未见表达。结论在体外培养过程中,大鼠脑神经干细胞的端粒酶活性和细胞增殖速率未见变化；神经干细胞分化后端粒酶活性丧失,可能是由于端粒酶逆转录酶停止表达所致。     

成年小鼠嗅球神经干细胞的培养和鉴定

目的 建立完善的成年小鼠嗅球神经千细胞分离培养和鉴定方法,探索新的成年神经干细胞种子来源. 方法 用无血清方法 分离培养成年小鼠嗅球来源的神经干细胞;用克隆培养、5-溴2-脱氧尿嘧啶核昔(BrdU)整合的方法 检验培养细胞的干细胞特性;用免疫荧光细胞化学的方法 检测BrdU、神经干细胞标记物巢蛋白(nestin)和SOX2、分化的细胞标记物Tuj1、胶质纤维酸性蛋白(GFAP)、04的表达. 结果 从成年小鼠嗅球能够分离、培养出具有自我更新、增殖能力的神经球.构成神经球的细胞呈nestin和SOX2阳性,它们分化后产生TuJ1阳性的神经元、GFAP阳性的星形胶质细胞、04阳性的少突胶质细胞. 结论 成年小鼠嗅球存在神经干细胞,其能够在体外进行培养、增殖、分化.是神经干细胞的新的种子来源.     

碱性成纤维细胞生长因子缓释微球促进神经干细胞生长的体外实验研究

目的 制备一种能够负载足量碱性成纤维细胞生长因子(bFGF)并且能够以理想的速度缓慢释放的载体. 方法 构建负载bFGF的缓释微球,并检测其体外释放过程.将bFGF缓释微球与神经干细胞共培养,以常规多次添加bFGF的神经干细胞培养组作为对照,用AlamarBlue法检测培养细胞的存活情况,ELISA法检测培养上清bFGF含量,定期观察细胞形态学变化,并进行巢蛋白荧光免疫细胞化学染色,检测神经干细胞标记物. 结果 AlamarBlue法检测结果显示,培养3d、5d时bFGF缓释微球组和常规培养组之间细胞增殖率差异有统计学意义(P＜0.05).ELISA法检测结果显示,仅负载bFGF缓释微球组能测量到培养上清中bFGF含量,大致维持在200 pg/mL水平.细胞形态学观察发现bFGF缓释微球组能够在培养第3天即形成神经干细胞球,并且在培养第7天仍保持较好透光度,保持较好的细胞活性.荧光免疫细胞化学染色发现bFGF缓释微球组培养的神经干细胞球巢蛋白染色阳性. 结论 本课题组制作的bFGF缓释微球材料具有较好的生物相容性.缓慢释放的bFGF能够满足神经干细胞生长需要,并且保持神经干细胞自身的细胞特性.该bFGF缓释微球安全有效,可应用于中枢神经系统损伤的在体实验研究.     

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。     

昆明种小鼠胚胎神经干细胞的分离与培养

背景: 对于神经干细胞的分离培养,目前多采用胰蛋白酶对组织细胞予以消化,但消化时间较难把握。 目的：采用胰酶消化与机械分离法相结合的方式对昆明种小鼠胚胎脑神经干细胞进行分离、培养,并进行初步的免疫组织化学检测。 设计、时间及地点：细胞学体外观察,于2006-10/2007-09在广西医科大学基础医学实验室完成。 材料：孕14~16 d的昆明种小鼠由广西医科大学实验动物中心提供。 方法：分离昆明种小鼠胎鼠的脑组织,经胰酶消化加机械吹打后,在加入碱性成纤维细胞生长因子和表皮细胞生长因子的B27无血清DMEM/F12培养基中培养。 主要观察指标：用免疫细胞化学方法鉴定分离的神经干细胞。 结果：培养24 h后,细胞以悬浮方式生长,聚集成团;48 h后形成由数十个细胞组成的细胞球,形态规则,体积大小不等,细胞无突起,形成典型的神经球,可传代扩增。免疫细胞化学染色结果示细胞巢蛋白呈阳性表达。 结论：在含有表皮细胞生长因子、碱性成纤维细胞生长因子的无血清B27培养基条件下,有利于小鼠胚胎神经干细胞的体外培养和传代增殖。     

Mash1在室管膜前下区神经干细胞向神经元分化中的作用

目的研究Mashl在室管膜前下区(SVZa)神经干细胞向神经元分化中的作用。方法体外分离培养新生0 d昆明小鼠的SVZa神经干细胞,原位杂交检测Mashl在SVZa神经干细胞的表达;构建Mashl与绿色荧光蛋白(GFP)正义、反义融合蛋白表达质粒,转染SVZa神经干细胞,GFP活体荧光标记SVZa神经干细胞;采用细胞计数和流式细胞仪检测在Mashl作用下SVZa神经干细胞分化为神经元的比例。结果体外培养的新生0 d昆明小鼠的SVZa神经干细胞Mashl原位杂交检测阳性;Mashl-GFP 组SVZa神经干细胞分化为神经元的比例明显高于空白对照组;Mashl-GFP-组 SVZa神经干细胞分化为神经元的比例明显低于空白对照组。结论体外培养的新生0 d昆明小鼠的SVZa神经干细胞表达Mashl;Mashl可以促进SVZa神经干细胞向神经元方向分化。     

不同体外诱导培养条件下新生鼠基底前脑神经干细胞增殖和分化为神经元的能力*☆

目的：研究神经干细胞的增殖、迁移和分化可为揭示神经系统的发生、发育过程提供可靠依据。观察表皮生长因子和碱性成纤维生长因子在体外刺激新生鼠基底前脑神经干细胞的增殖情况，及其各自诱导神经干细胞分化成神经元的能力。 方法：实验于2005-12/2006-07在广州医学院解剖学教研室完成。①动物：清洁级新生24 h内的SD大鼠30只，实验过程中对动物的处置符合动物伦理学标准。②实验方法：新生鼠在无菌条件下取脑，分离出基底前脑，胰蛋白酶消化，离心过滤制备单细胞悬液，接种于含B27的DMEM/F12培养基培养瓶中，每瓶40~60万个细胞，加入终浓度均为10μg/L的表皮生长因子和碱性成纤维生长因子刺激生长，在体外进行神经干细胞的克隆培养，传代培养过程中加入终浓度为6 mg/L BrdU用于标记神经球，设立3组，各自加入体积分数为0.1的小牛血清、终浓度均为10μg/L的表皮生长因子、碱性成纤维生长因子，对培养得到的神经干细胞进行诱导分化。③实验评估：免疫荧光染色检测神经干细胞巢蛋白抗原的表达，并用BrdU标记和免疫荧光证实其增殖能力。免疫荧光染色检测不同诱导条件下神经干细胞向神经元分化的能力。 结果：①细胞形态观察：从新生鼠基底前脑成功分离出神经干细胞，原代培养呈透亮的圆球形，2~3 d后细胞数目明显减少，部分细胞开始分裂。1周左右培养瓶中出现许多由数十到数百个细胞组成的悬浮生长的细胞球，球中的细胞形态规则，边界清楚，折光性较强，胞浆颜色较深，核/浆比较大。该细胞具有连续增殖能力，可以传代培养。②巢蛋白抗原的表达：传代神经球中的细胞均呈巢蛋白抗原阳性。③BrdU标记检测：克隆球中的细胞均为BrdU阳性，表明克隆球是由不断分裂增殖的细胞组成。④诱导分化结果：在体积分数为0.1小牛血清、终浓度均为10μg/L的表皮生长因子、碱性成纤维生长因子诱导条件下，神经干细胞分化为神经元的比例分别为20%，22%，40%。 结论：①表皮生长因子和碱性成纤维生长因子在体外能够刺激新生鼠基底前脑神经干细胞连续增殖，且具有胚胎源性。②以血清作为对照，碱性成纤维生长因子诱导神经干细胞向神经元分化的能力强于表皮生长因子。     

经枕大池神经干细胞移植治疗大鼠创伤性脑损伤的研究

目的 将神经干细胞经枕大池移植到创伤性脑损伤模型大鼠蛛网膜下腔中并观察其存活、迁移和分化,从而为神经干细胞的体内存活、迁移和分化机理研究和临床应用提供实验依据.方法 体外培养BrdU标记的胚胎神经干细胞并应用免疫荧光细胞化学染色对BrdU、神经干细胞标记物nestin的表达进行鉴定:采用Feeney自由落体撞击法制做大鼠脑损伤模型,伤后24 h将BrdU标记的胚胎神经十细胞经立体定向注射移植到蛛网膜下腔;制作大鼠脑绢织石蜡切片,应用免疫组织化学染色检测BrdU、微管相关蛋白2(MAP2)、胶质纤维酸性蛋白(GFAP)表达;伤前24h、伤后24 h及1、2周行动物运动神经功能评分.结果 免疫荧光检测显示神经球的表面细胞表达nestin及BrdU:免疫组织化学染色检测到脑内损伤灶存在BrdU阳性神经干细胞、MAP2阳性神经元和GFAP阳性胶质细胞;接受神经十细胞移植的大鼠神经运动功能评分的恢复较对照组有明显提高,差异有统计学意义(P<0.05).结论 经枕大池移植到脑损伤大鼠蛛网膜下腔中的神经干细胞能存活且具有远距离迁移能力,并明显有助于脑损伤大鼠神经运动功能的恢复.     

胚胎大鼠脑纹状体和中脑神经干细胞的培养

目的研究大鼠脑不同部位胚胎神经干细胞的增殖分化特性。方法采用无血清培养基分离和培养大鼠脑的纹状体和中脑的神经干细胞,通过巢蛋白(nestin)表达和5-溴脱氧尿嘧啶(5-bromo-2'-deoxyuridine BrdU)染色,鉴定细胞的增殖能力;通过新生神经元、星形胶质细胞和少突胶质细胞的特异性免疫细胞化学染色,鉴定培养细胞的多潜能性。通过酪氨酸羟化酶的染色(tyrosine hydroxylase,TH)鉴定多巴胺神经元。结果二者在体外培养都可增殖成球,并能分化成神经系统3个谱系的细胞。纹状体增殖传代3个月,中脑培养细胞增殖维持3周。中脑干细胞分化TH阳性细胞比例高于纹状体。结论培养的胎鼠脑细胞是神经干细胞。纹状体干细胞增殖能力高于中脑干细胞,中脑干细胞更倾向于分化成TH阳性细胞。     

Dynamic behavior of cells within neurospheres in expanding populations of neural precursors

Large-scale expansion of neural stem and progenitor cells will be essential for clinically treating the large number of patients suffering from neurodegenerative disorders such as Parkinson's disease. Other applications of neural stem cell technology include further research in areas such as neural development or drug testing. Neural stem cells can be grown in vitro as tissue aggregates known as neurospheres, and in the current study, experiments were performed to determine the spatial arrangement and behavior of the cells within the neurosphere structure. A protocol utilizing sulfonated lipophilic fluorescent dyes was developed to effectively label populations of neural stem and progenitor cells without compromising cell density during culture. Cells retained the labels for at least 7 days. Using the labeling protocol, we discovered that the cells within the neurospheres were mobile and, moreover, the cells on the periphery of the neurospheres could migrate into the center of the neurospheres. Most important, the mixing time of two merging neurospheres was observed to be the same order of magnitude as the neural stem cell doubling time (approximately 20 h). This study is the first to show that the neurosphere system is dynamic, and these results will serve as a stepping stone to more in-depth studies of the neurosphere microenvironment.     

Prospective characterization of neural stem cells by flow cytometry analysis using a combination of surface markers

Neural stem cells (NSCs) with self-renewal and multilineage differentiation properties can potentially repair degenerating or damaged neural tissue. Here, we have enriched NSCs from neurospheres, which make up a heterogeneous population, by fluorescence-activated cell sorting (FACS) with antibodies against syndecan-1, Notch-1, and integrin-beta1, which were chosen as candidates for hematopoietic cell-or somatic stem cell-markers. Antigen-positive cells readily initiated neurosphere formation, but cells lacking these markers did so less readily. Doubly positive cells expressing both syndecan-1 and Notch-1 underwent neurosphere formation more efficiently than did singly positive cells. The progeny of sorted cells could differentiate into neurons and glial cells both in vitro and in vivo. These antibodies were also useful for isolating cells from the murine embryonic day 14.5 brain that efficiently formed neurospheres. In contrast, there was no distinct difference in neurosphere formation efficiency between Hoechst 33342-stained side population cells and main population cells, although the former are known to have a stem cell phenotype in various tissues. These results indicate the usefulness of syndecan-1, Notch-1, and integrin-beta1 as NSC markers.     

A comparison of proliferative capacity and passaging potential between neural stem and progenitor cells in adherent and neurosphere cultures

Neural stem and progenitor cells (NSPCs) can be isolated from the fetal or adult brain and expanded in culture for potential use in basic research, drug discovery and cell therapy. In the present study, two culture systems have been commonly used to maintain and expand NSPCs isolated from mammalian CNS: neurosphere and adhesive substrate-bound monolayer culture. NSPCs were isolated from the neuroepithelium of E14 embryonic rat cerebral cortex and maintained and expanded on fibronectin substrates or within neurospheres in serum-free medium. Ultrastructural study under transmission electron microscope revealed similar characteristics of immature morphology of NSPCs in adherent and neurosphere cultures. NSPCs cultured on adherent substrates and within neurospheres shared the properties of self-renewal and multipotency, but little is known about proliferation capacity and passaging potential of adherent NSPCs compared to neurosphere culture. We found that the self-renewal capacity of NSPCs in adherent culture was higher than that in neurosphere culture in the P1 and P3 passages, and reduced after the P5 passage. At the same time, comparative analysis using BrdU incorporation and immunostaining for nestin indicated that NSPCs grew significantly faster in primary cultures on adherent substrates than within neurospheres. Whereas, NSPCs in adherent culture could not maintain such robust growth for more than 6 passages. The growth of NSPCs within neurospheres was slower than that in adherent culture, but increased steadily and could be maintained for more than 10 passages. These data provide useful information for large scale in vitro expansion of NSPCs required by potential drug screening and cell therapy.     

Growth and differentiation of neural stem cells in a three-dimensional collagen gel scaffold

Collagen protein is an ideal scaffold material for the transplantation of neural stem cells. In this study, rat neural stem cells were seeded into a three-dimensional collagen gel scaffold, with suspension cultured neural stem cells being used as a control group. Neural stem cells, which were cultured in medium containing epidermal growth factor and basic fibroblast growth factor, actively expanded and formed neurospheres in both culture groups. In serum-free medium conditions, the processes extended from neurospheres in the collagen gel group were much longer than those in the suspension culture group. Immunofluorescence staining showed that neurospheres cultured in collagen gels were stained positive for nestin and differentiated cells were stained positive for the neuronal marker βIII-tubulin, the astrocytic marker glial fibrillary acidic protein and the oligodendrocytic marker 2’,3’-cyclic nucleotide 3’-phosphodiesterase. Compared with neurospheres cultured in suspension, the differentiation potential of neural stem cells cultured in collagen gels increased, with the formation of neurons at an early stage. Our results show that the three-dimensional collagen gel culture system is superior to suspension culture in the proliferation, differentiation and process outgrowth of neural stem cells.     

A novel fixative for immunofluorescence staining of CD133-positive glioblastoma stem cells

Isolation of glioblastoma stem cells requires incubation of tumor cells in a neural stem cell media. Neurospheres containing these glioblastoma stem cells are formed after approximately a five-day period. These cells can then be analyzed for the presence of stem cell markers. Immunofluorescence staining for these markers can serve as a valuable tool for analyzing the intact neurosphere directly in stem cell media. Here we present the use of a novel fixative (1,4-benzoquinone) for immunoflourescence staining of neurospheres.     

Hepatocyte growth factor promotes neuronal differentiation of neural stem cells derived from embryonic stem cells

We previously reported that hepatocyte growth factor (HGF) promoted proliferation of neurospheres and neuronal differentiation of neural stem cells (NSCs) derived from mouse embryonic brain. In this study, spheres from mouse embryonic stem (ES) cells were generated by floating culture following co-culture on PA6 stromal cells. In contrast to the behavior of the neurospheres derived from embryonic brain, addition of HGF to the growth medium of the floating cultures decreased the number of spheres derived from ES cells. When spheres were stained using a MAP-2 antibody, more MAP-2-positive cells were observed in spheres cultured with HGF. When HGF was added to the growth and/or differentiation medium, more MAP-2-positive cells were also obtained. These results suggest that HGF promotes neuronal differentiation of NSCs derived from ES cells.     

Isolation of neural stem cells from the forebrain of deceased early postnatal and adult rats with protracted post-mortem intervals

Neural stem cells were isolated from deceased early postnatal and adult rats with varying post-mortem intervals. Animals were killed by deep anesthesia and stored in a refrigerator at 4 degrees C for 1-6 days before use. Neurospheres were obtained from the forebrain tissue, including the lateral ventricle in the early postnatal rats, and from the striatal wall of lateral ventricle, including the subventricular zone (SVZ) in adult rats. The number of neurospheres obtained in the primary culture from early postnatal animals was much larger than that from the adult rats. There was no significant difference in the population of neurospheres between the living and the deceased animals at least within 2 days after death. A few neurospheres were still obtainable at 6 days after death in early postnatal animals, but almost no neurospheres were obtained at 5 days after death in the adult rats. The differentiation capacity of neural stem cells in neurospheres was similar between the deceased and the living animals. The rich vascular bed in the SVZ of the lateral ventricle suggests that the vascular architecture might be in part responsible for the survival of the neural stem cells in the deceased animals. Neurosphere cells derived from deceased adult rats survived and differentiated mainly into glial cells in the host spinal cord tissue after transplantation into the injured spinal cord. Therefore, the neural stem cells from deceased animals express the same phenotypes as those from living animals in terms of neurosphere formation, proliferation, and differentiation at least 2 days after death. The neural stem cells from cadavers have great significance in terms of their clinical use as homografts for CNS regeneration.     

人类神经干细胞的长期培养和传代

目的 探讨人类神经干细胞的体外培养条件及其传代的方法。方法 采用机械方法从胎脑中分离神经细胞，应用N2培养基进行培养，bFGF和EGF刺激细胞扩增；传统方法和对神经球切割的方法进行传代培养；应用免疫组织化学染色对培养的细胞及其分化的细胞进行鉴定。结果 从胎脑当中成功培养出人类的神经干细胞，培养条件下呈悬浮状态生长，形成神经球，绝大多数的细胞表达波形蛋白和Musashil两种神经干细胞的标志物；这种细胞可分化为神经元和星型胶质细胞，早期的培养有少量的少突胶质细胞；在这种培养条件下，神经干细胞生长速度较慢，而采用切割神经球的方法保持了细胞间的，神经干细胞可获得较大的扩增速度。结论 在体外的培养条件下，可从胎脑组织中培养出神经干细胞，它可做为中枢神经系统疾病移植治疗的潜在细胞来源。     

神经干细胞原代培养方法的优化

目的 探讨低浓度胰酶不同消化分离时间对体外培养新生大鼠海马NSCs增殖与凋亡的影响.方法 取出生24 h内SD大鼠海马组织,以1.25 g/L胰酶37℃分别消化5、10、15、20和25min(依次为A～E组),获得单细胞悬液后进行培养.通过台盼蓝染色计数、细胞形态观察和神经球数目比较不同消化时间对NSCs活力和生长的影响;用5-溴-2脱氧尿嘧啶核苷(BrdU)标记法检测NSCs的增殖能力;用免疫荧光细胞化学法检测BrdU、nestin的表达:用Annexin V-FITC/PI染色和流式细胞仪检测细胞凋亡率.结果 原代和传代培养的NSCs都能快速增殖并形成神经球;免疫荧光染色结果显示神经球细胞均表达NSCs特异性标志物nestin;所获得的细胞能将BrdU结合到细胞核中;各组培养3、5、7 d后,C组(消化15 min)NSCs成球数最多,BrdU标记克隆率最高,细胞凋亡率最低,与其他组比较差异有统计学意义(P<0.05).结论 体外分离培养的新生大鼠海马NSCs具有增殖能力,1.25 g/L胰酶在不同消化时间对NSCs增殖能力和凋亡率的影响有所不同,消化时间过长或过短都会抑制NSCs增殖,诱导NSCs凋亡,且消化时间越长NSCs的凋亡率越高.

Abstract：

Objective To study the influence of digestion times of low concentration trypsin on the proliferation and apoptosis of neural stem cells (NSCs) in the hippocampus of neonate rats.Methods Hippocampus of neonatal rats (within 24 h) were taken out, and treated with trypsin at 1.25g/L concentration and 37 ℃ for 5, 10, 15, 20 and 25 minutes; unicellular suspension was then successfully got and primary culture and subculture were performed. Effects of trypsinization on cell viability and growth of NSCs were compared by observing the cell morphology and Trypan blue staining.The 5-bromodeoxyuridine labeling was performed to assess the self-renewing and proliferative activities of NSCs. Fluorescence immunocytochemistry was carried out to examine the expressions of BrdU and nestin. Apoptosis was measured by Annexin V-FITC/PI assay and flow cytometry. Results Primary and passage culture of NSCs enjoyed rapid proliferation and formation of neurospheres. The neurosphere cells expressed NSCs specific marker nestin by immunofluorescence; all the neurosphere cells could incorporate BrdU into the nucleus; of the neurospheres obtained from the 3rd, 5th and 7th d, those digested for 15 rain enjoyed the highest level of NSCs neurospheres, the highest BrdU labeled clone and the lowest cell apoptosis as compared with those digested for 5, 10, 20 and 25 min (P<0.05). Conclusion The NSCs isolated from the hippocampus of neonatal rats have the ability of proliferation in vitro. And 1.25 g/L concentration of trypsin with digestion times could positively change the proliferative and apoptosis capacity of NSCs: too short or long digestion times can inhibit the proliferation of NSCs and induce the apoptosis of NSCs; the longer the digestion time, the higher the apoptosis of NSCs.