神经干细胞-施万细胞-聚乳酸-羟基乙酸共聚物支架移植对脊髓损伤大鼠的影响

目的探讨种植神经干细胞(NSCs)与施万细胞(SCs)的聚乳酸-羟基乙酸共聚物(PLGA)支架移植促进脊髓损伤大鼠神经功能恢复的作用及机制。方法体外培养NSCs 和SCs,以PLGA 为支架移植入大鼠T8 半横断脊髓损伤处。实验动物随机分为PLGA组、PLGA+NSCs 组和PLGA+NSCs+SCs 组。术前和术后进行皮层运动诱发电位(CMEPs)检查及BBB评分;然后在同侧或对侧进行T6再次半横断,并进行CMEPs 检测及BBB 评分。结果CMEPs 的恢复率及波幅在PLGA+NSCs+SCs 组最高。移植后,大鼠BBB 评分逐渐改善;在移植后第2 周及以后,PLGA+NSCs 组和PLGA+NSCs+SCs 组的BBB 评分显著高于PLGA 组(P<0.001)。同侧再次半横断后,CMEPs 消失, BBB 评分快速恢复;对侧再次半横断后,大鼠双下肢完全瘫痪。结论种植NSCs 和SCs 的PLGA支架移植有利于脊髓损伤功能重建,再生轴突可能形成了功能性连接;但是同侧再生轴突对脊髓功能的恢复作用有限。     

乙交酯-丙交酯共聚物-细胞复合体移植治疗脊髓损伤

目的:观察神经干细胞、许旺细胞和组织工程支架材料乙交酯-丙交酯共聚物于大鼠髓内共移植后的生物相容性,及其对大鼠损伤脊髓形态和功能的修复作用。方法:实验于2005-05/2006-09在首都医科大学附属北京市神经外科研究所损伤修复实验室完成。①实验材料:健康成年雌性Wistar大鼠36只,随机数字表法分为单纯支架组、神经干细胞 支架复合体组、神经干细胞 许旺细胞 支架复合体组,12只/组。乙交酯-丙交酯共聚物由中科院化学研究所医用高分子材料中心提供。②实验方法:各组大鼠均建立脊髓T9半横断损伤模型。神经干细胞 许旺细胞 支架复合体组取2×1010L-1的许旺细胞、神经干细胞各10μL接种于乙交酯-丙交酯共聚物支架内,神经干细胞 支架复合体组取2×1010L-1的神经干细胞10μL接种于乙交酯-丙交酯共聚物支架内,单纯支架组取10μLDMEM培养液置于乙交酯-丙交酯共聚物支架内,于脊髓缺损处分别植入对应的复合物。③实验评估:应用电镜观察乙交酯-丙交酯共聚物支架的降解及轴突的再生状况;应用BBB评分和电生理技术检测大鼠脊髓功能性的恢复情况。结果:36只Wistar大鼠均进入结果分析。①行为学观察结果:移植术后4,12周,神经干细胞 支架复合体组、神经干细胞 许旺细胞 支架复合体组大鼠的后肢运动功能BBB评分均好于单纯支架组(P<0.01),其中神经干细胞 许旺细胞 支架复合体组尤为明显。②神经电生理检查结果:在脊髓半横断损伤后即刻,所有动物的体感诱发电位和运动诱发电位波幅都明显减低甚至消失。移植术后4周,神经干细胞 支架复合体组、神经干细胞 许旺细胞 支架复合体组大鼠的体感诱发电位和运动诱发电位波幅均有所恢复;至移植术后12周恢复明显。单纯支架组移植术后4,12周体感诱发电位和运动诱发电位波幅无明显变化。③电镜观察结果:扫描电镜下,随着时间的延长各组植入的乙交酯-丙交酯共聚物逐渐降解。透射电镜下,各组植入材料正中横断面可见新生的无髓及有髓神经纤维,至12周时神经干细胞 许旺细胞 支架复合体组最明显。结论:乙交酯-丙交酯共聚物在大鼠损伤的脊髓内具有良好的生物相容性;其与神经干细胞、许旺细胞共移植能够明显促进脊髓半横断损伤大鼠的脊髓轴突再生,并改善肢体的运动功能。     

人牙髓细胞复合不同孔径羟基磷灰石/磷酸三钙支架材料的生物学行为

背景:有文献表明,通过组织工程的方法将人牙髓细胞复合羟基磷灰石/磷酸三钙多孔支架材料修复牙缺损具有可行性.然而究竟多大孔径的支架材料最有利于人牙髓细胞的生长及分化,至今尚无定论.目的:观察人牙髓细胞复合不同孔径羟基磷灰石/磷酸三钙支架材料后黏附、增殖和分化等生物学行为.方法:人牙髓细胞接种至3种不同孔径的羟基磷灰石/磷酸三钙材料上,采用荧光显微镜以及扫描电镜检测细胞在材料表面的黏附生长情况,然后通过细胞的黏附率实验与MTT比色法观察人牙髓细胞在材料表面的黏附与增殖特性.不同孔径的羟基磷灰石/磷酸三钙支架复合人牙髓细胞后分别用生长培养基和矿化诱导液培养,于接种后第4,7,10天检测碱性磷酸酶活性.结果与结论:人牙髓细胞在3种不同孔径支架材料表面和孔隙内均能顺利黏附并增殖.其中100～300 μm组支架材料黏附率最高,MTT结果显示接种3 d后300～500 μm组能较好地促进细胞增殖.培养10 d后,复合在100～300 μm和300～500μm材料上的人牙髓细胞,其碱性磷酸酶活性显著高于500-700 μm组.提示与500～700 μm孔径相比,孔径为100～300μm和300～500 μm的羟基磷灰石/磷酸三钙材料能更好地促进人牙髓细胞黏附、增殖和分化.     

促红细胞生成素促进脊髓损伤大鼠移植神经干细胞存活和迁移

背景:如何有效促进移植入脊髓损伤组织内的神经干细胞存活和迁移,是目前神经修复研究的重点。目的:观察促红细胞生成素对脊髓损伤大鼠移植神经干细胞存活、增殖和迁移的影响。方法:将60只SD大鼠随机分为3组,均制备脊髓横断损伤模型。造模7d,神经干细胞移植组和促红细胞生成素组于脊髓损伤处移植BrdU标记的神经干细胞7μL(1×109L-1),脊髓损伤对照组移植DMEM/F12培养基;促红细胞生成素组腹腔内注射促红细胞生成素5000U/kg,1次/d,连续注射7d,其余两组注射等量生理盐水。于细胞移植后8周取损伤脊髓组织。结果与结论:造模2周后,神经干细胞移植组和促红细胞生成素组BBB评分明显高于脊髓损伤对照组(P<0.05),造模4周后,促红细胞生成素组BBB评分明显高于神经干细胞移植组(P<0.05)。免疫荧光染色显示促红细胞生成素组大鼠损伤脊髓组织BrdU阳性细胞数量及迁移距离均大于神经干细胞移植组(P<0.05)。说明促红细胞生成素能促进损伤脊髓组织原位移植的神经干细胞的存活与迁移,加速神经功能修复。     

神经营养素-3基因修饰骨髓间充质干细胞的明胶海绵圆柱体支架移植促进大鼠全横断脊髓损伤部分结构和功能修复的研究

目的:探讨神经营养素-3(NT-3)基因修饰骨髓间充质干细胞(MSCs)的明胶海绵圆柱体支架移植对大鼠全横断脊髓损伤部分结构和功能修复的影响。方法:选取15只SD大鼠,随机分成3组:①NT-3基因修饰MSCs联合明胶海绵圆柱体支架移植组(NT-3-MSCs组);②MSCs联合明胶海绵圆柱体支架移植组(MSCs组);③单纯明胶海绵圆柱体支架移植组(control组)。在脊髓全横断后施行上述支架移植,在一定时间点比较3组动物功能恢复情况及其脊髓损伤区的结构变化。结果:NT-3-MSCs组BBB功能评分、移植的MSCs存活数、神经丝蛋白-200(NF-200)阳性纤维计数和平均空洞面积均优于其余组别(P<0.05)。结论:NT-3基因修饰MSCs联合明胶海绵圆柱体支架移植能够促进大鼠脊髓损伤部分结构和功能的修复,为临床治疗脊髓损伤提供实验依据。     

NEP1-40基因修饰的神经干细胞移植对脊髓损伤大鼠行为学恢复的影响

目的通过与单纯的神经干细胞移植进行比较,探讨NEP1-40基因修饰的神经干细胞移植对脊髓损伤大鼠行为学恢复的影响。方法从孕18 d的Sprague-Dawley（SD）大鼠胚胎大脑皮质中分离获得原代神经干细胞,体外培养及传代后采用巢蛋白免疫荧光染色进行鉴定。采用已成功构建的慢病毒载体将NEP1-40基因导入第3代神经干细胞内建立NEP1-40基因修饰的神经干细胞。将30只SD大鼠在第9胸椎水平进行脊髓右侧半切后随机分为3组,每组各10只,伤后第7天在损伤局部分别植入细胞培养液（损伤组）、神经干细胞（NSC组）及NEP1-40基因修饰的神经干细胞（NEP1-40-NSC组）。另取10只仅行第8~10胸椎椎板切除,设置为假手术组。细胞移植前和移植后8周通过Basso-Beattle-Bresnahan（BBB）运动功能评分及网格测试评价神经功能恢复情况。结果细胞移植后8周,BBB测试及网格测试结果显示：损伤组大鼠BBB评分最低且网格摔倒次数最多,单纯神经干细胞移植组BBB评分较之增高且网格摔倒次数减少（P〈0.01）,而NEP1-40基因修饰的神经干细胞移植组BBB评分最高且网格摔倒次数最少,和前两组相比差异均有统计学意义（P〈0.01）。结论 NEP1-40基因修饰能进一步提高单纯神经干细胞移植对于大鼠脊髓损伤后行为功能恢复的治疗效果,为研究神经干细胞移植治疗脊髓损伤提供了新的思路和实验依据。     

促红细胞生成素促进脊髓损伤大鼠移植神经干细胞存活和迁移

背景：如何有效促进移植入脊髓损伤组织内的神经干细胞存活和迁移,是目前神经修复研究的重点。目的：观察促红细胞生成素对脊髓损伤大鼠移植神经干细胞存活、增殖和迁移的影响。方法：将60只SD大鼠随机分为3组,均制备脊髓横断损伤模型。造模7d,神经干细胞移植组和促红细胞生成素组于脊髓损伤处移植BrdU标记的神经干细胞7μL（1×109L-1）,脊髓损伤对照组移植DMEM/F12培养基;促红细胞生成素组腹腔内注射促红细胞生成素5000U/kg,1次/d,连续注射7d,其余两组注射等量生理盐水。于细胞移植后8周取损伤脊髓组织。结果与结论：造模2周后,神经干细胞移植组和促红细胞生成素组BBB评分明显高于脊髓损伤对照组（P〈0.05）,造模4周后,促红细胞生成素组BBB评分明显高于神经干细胞移植组（P〈0.05）。免疫荧光染色显示促红细胞生成素组大鼠损伤脊髓组织BrdU阳性细胞数量及迁移距离均大于神经干细胞移植组（P〈0.05）。说明促红细胞生成素能促进损伤脊髓组织原位移植的神经干细胞的存活与迁移,加速神经功能修复。     

绿色荧光蛋白标记的大鼠神经干细胞移植于损伤脊髓后的迁移和存活

目的观察神经干细胞在体内的迁移和存活。方法体外培养胎鼠脊髓神经干细胞,用表达绿色荧光蛋白(GFP)的慢病毒载体进行转染,以乙交酯-丙交酯共聚物(PLGA)为支架移植入大鼠T9半横断脊髓损伤处。移植后1个月在荧光显微镜下观察神经干细胞在脊髓内的迁移,并计算其存活率。结果神经干细胞表达强烈的绿色荧光。细胞移植后1个月,在损伤脊髓的头端和尾端都可见GFP阳性细胞,计算出的存活率为(1.4911±0.0313)%。结论GFP标记的神经干细胞移植入大鼠损伤脊髓后向脊髓组织内迁移并有少数存活。     

体外转染绿色荧光蛋白基因的肌源性干细胞移植修复大鼠脊髓损伤

背景:肌源性干细胞易于提取、分离及扩增,在特定条件下可分化为骨、软骨、肌肉等中胚层组织细胞,还可以跨胚层分化为神经细胞等,是组织工程临床用于脊髓损伤修复的理想种子细胞.目的:观察肌源性千细胞移植对脊髓半切损伤大鼠运动功能的修复作用.方法:40只成年SD大鼠随机数字表法分为移植组和对照组,每组20只.均进行脊髓半切损伤,伤后9 d,移植组于伤处移植体外转染绿色荧光蛋白基因的大鼠肌源性干细胞,而对照组仅注射等量PBS,于移植后1,2,3,4周用斜板实验和BBB评分测大鼠的运动功能,同时进行损伤脊髓取材、快速冰冻切片进行荧光显微镜观察.结果与结论:所有大鼠脊髓半切损伤手术均成功.术后无动物死亡.肌源性干细胞移植后1周,移植组与对照组均有所恢复,斜板实验和BBB评分差异无显著性意义(P>0.05;2～4周移植组恢复明显较好,斜板实验和BBB评分显著高于对照组(P<0.05),移植组后肢活动与前后肢活动的协调性明显优于对照组.荧光显微镜观察经诱导分化和基因标记的肌源性干细胞在损伤脊髓组织局部生长良好,并且有沿着脊髓神经束向头尾两侧迁移的趋势.提示脊髓半切损伤大鼠经肌源性于细胞移植后能在损伤脊髓组织局部长期存活并明显改善其运动功能,肌源性干细胞移植对脊髓半切损伤大鼠有修复作用.     

神经干细胞移植治疗脊髓损伤

背景:研究已证实神经干细胞能促进脊髓损伤大鼠神经功能的恢复,但对移植细胞在体内的增殖、分化、迁移的研究有限。目的:观察神经干细胞移植对脊髓损伤大鼠后肢运动功能修复的影响。方法:SD大鼠制成T10脊髓全横断损伤模型,于造模成功后1周采用局部微量注射法。随机数字表法分为3组:损伤对照组仅打开椎管暴露脊髓;移植对照组:注射10μLDMEM/F12培养液;细胞移植组:造模后移植浓度为1.0×109L-1的神经干细胞悬液10μL。移植后通过不同时间点BBB行为评分、病理组织学、免疫荧光技术评价大鼠脊髓功能修复情况及移植细胞在体内的存活、迁移、分化。结果与结论:在体外成功建立SD大鼠海马源性神经干细胞培养体系;移植对照组、细胞移植组大鼠随着时间延长BBB评分均不同程度提高,从移植后2周起细胞移植组大鼠评分明显高于移植对照组(P<0.05);神经干细胞移植后能够在体内继续存活、迁移并且分化为NF-200、GFAP表达阳性的神经元及星形胶质细胞。提示神经干细胞移植治疗脊髓损伤是一种有效的方法。     

Local delivery of FTY720 and NSCs on electrospun PLGA scaffolds improves functional recovery after spinal cord injury

Spinal cord injury (SCI) is a common issue in the clinic that causes severe motor and sensory dysfunction below the lesion level. FTY720, also known as fingolimod, has recently been reported to exert a positive effect on the recovery from a spinal cord injury. Through local delivery to the lesion site, FTY720 effectively integrates with biomaterials, and the systemic adverse effects are alleviated. However, the effects of the proper mass ratio of FTY720 in biomaterials on neural stem cell (NSC) proliferation and differentiation, as well as functional recovery after SCI, have not been thoroughly investigated. In our study, we fabricated electrospun poly (lactide-co-glycolide) (PLGA)/FTY720 scaffolds at different mass ratios (0.1%, 1%, and 10%) and characterized these scaffolds. The effects of electrospun PLGA/FTY720 scaffolds on NSC proliferation and differentiation were measured. Then, a rat model of spinal transection was established to investigate the effects of PLGA/FTY720 scaffolds loaded with NSCs. Notably, 1% PLGA/FTY720 scaffolds exerted the best effects on the proliferation and differentiation of NSCs and 10% PLGA/FTY720 was cytotoxic to NSCs. Based on the Basso, Beattie, and Bresnahan (BBB) score, HE staining and immunofluorescence staining, the PLGA/FTY720 scaffold loaded with NSCs effectively promoted the recovery of spinal cord function. Thus, FTY720 properly integrated with electrospun PLGA scaffolds, and electrospun PLGA/FTY720 scaffolds loaded with NSCs may have potential applications for SCI as a nerve implant.

Spinal cord injury (SCI) is a common issue in the clinic that causes severe motor and sensory dysfunction below the lesion level.     

神经干细胞移植治疗脊髓损伤

背景：研究已证实神经干细胞能促进脊髓损伤大鼠神经功能的恢复,但对移植细胞在体内的增殖、分化、迁移的研究有限。目的：观察神经干细胞移植对脊髓损伤大鼠后肢运动功能修复的影响。方法：SD大鼠制成T10脊髓全横断损伤模型,于造模成功后1周采用局部微量注射法。随机数字表法分为3组：损伤对照组仅打开椎管暴露脊髓;移植对照组：注射10μLDMEM/F12培养液;细胞移植组：造模后移植浓度为1.0×109L-1的神经干细胞悬液10μL。移植后通过不同时间点BBB行为评分、病理组织学、免疫荧光技术评价大鼠脊髓功能修复情况及移植细胞在体内的存活、迁移、分化。结果与结论：在体外成功建立SD大鼠海马源性神经干细胞培养体系;移植对照组、细胞移植组大鼠随着时间延长BBB评分均不同程度提高,从移植后2周起细胞移植组大鼠评分明显高于移植对照组（P〈0.05）;神经干细胞移植后能够在体内继续存活、迁移并且分化为NF-200、GFAP表达阳性的神经元及星形胶质细胞。提示神经干细胞移植治疗脊髓损伤是一种有效的方法。     

高压氧联合神经干细胞移植治疗大鼠脊髓损伤

背景：单纯神经干细胞移植已应用于对受损脊髓组织的修复。目的：以神经干细胞移植同时应用高压氧治疗大鼠脊髓损伤,观察联合作用对脊髓损伤大鼠运动功能恢复的影响。方法：雌性SD大鼠60只,以半切法制成胸段脊髓半横断大鼠模型。随机分成单纯损伤组、神经干细胞移植组及高压氧治疗组,每组20只。伤后第4周取材行病理切片苏木精-伊红染色及BrdU免疫组织化学染色,第8周取材行辣根过氧化物酶示踪,透射电镜观察轴突的再生情况,通过体感诱发电位观察神经电生理恢复情况。造模后1,2,4,6,8周进行BBB评分和斜板实验等运动功能检测。结果与结论：观察伤后4周病理切片,单纯损伤组未见神经轴索通过,神经干细胞移植组可见少量神经轴索样结构,高压氧治疗组可见较多神经轴索样结构。BrdU的阳性细胞数及辣根过氧化物酶阳性神经纤维数,高压氧治疗组最多,神经干细胞移植组次之,单纯损伤组最少,且各组之间差异有显著性意义（P〈0.05）。透射电镜下神经干细胞移植组、高压氧治疗组正中横断面可见新生的无髓及有髓神经纤维。高压氧治疗组大鼠体感诱发电位的潜伏期短于神经干细胞移植组,波幅高于神经干细胞移植组（P〈0.05）,明显优于单纯损伤组（P〈0.01）。伤后4周神经干细胞移植组、高压氧治疗组大鼠后肢运动功能均有较明显恢复,高压氧治疗组较神经干细胞移植组恢复快（P〈0.05）;单纯损伤组亦有所恢复,但程度较轻。提示神经干细胞移植对于脊髓损伤大鼠后肢功能的恢复有促进作用,联合应用高压氧有协同效果。     

Development of poly(lactide‐co‐glycolide) scaffold‐impregnated small intestinal submucosa with pores that stimulate extracellular matrix production in disc regeneration

The pore size and microstructure of scaffolds influences cell attachment, migration, proliferation and ingrowth, but the optimal pore size of scaffolds for disc tissue formation is not clearly understood. We developed porous poly(lactide‐co‐glycolide) (PLGA) scaffolds with various pore sizes for nucleus pulposus (NP) cell cultures and examined the effects of pore size on cell ingrowth and extracellular matrix (ECM) synthesis. High cell density in the small pores of scaffolds promotes collagen synthesis and cell migration through interconnected pores. Scaffolds with large pores exhibited slower cell proliferation and collagen synthesis. Guided by these results, we investigated a novel, biodegradable, synthetic/natural hybrid scaffold composed of PLGA and small intestinal submucosa (SIS) (PLGA–SIS) with the proper pore size for NP regeneration. We tested the morphological and physical properties of PLGA–SIS scaffolds and initial cell attachment and ECM production of NP in scaffolds. The mechanical and degradable properties of the PLGA–SIS scaffold were superior to those of SIS sponge and were similar to the properties of PLGA scaffold. NP cells grown on PLGA–SIS scaffold exhibited higher initial cell adhesion and ECM production than those grown on pure PLGA scaffold in a biological assay. In conclusion, this study suggests that a proper pore size of scaffolds is critical in NP regeneration, and that PLGA–SIS scaffolds with suitable pores might be useful as substrates for tissue‐engineered biodiscs. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of pore sizes of PLGA scaffolds on mechanical properties and cell behaviour for nucleus pulposus regeneration in vivo

This study investigated the influence of pore sizes of poly(lactic‐co‐glycolic acid) (PLGA) scaffolds on the compressive strength of tissue‐engineered biodiscs and selection of the best suitable pore size for cells to grow in vivo. PLGA scaffolds were fabricated by solvent casting/salt‐leaching with pore sizes of 90–180, 180–250, 250–355 and 355–425 µm. Nucleus pulposus (NP) cells were seeded on PLGA scaffolds with various pore sizes. Each sample was harvested at each time point, after retrieval of PLGA scaffolds seeded with NP cells, which were implanted into subcutaneous spaces in nude mice at 4 and 6 weeks. MTT assay, glycosaminoglycan (GAG) assay, haematoxylin and eosin (H&E) staining, safranin O staining and immunohistochemistry (for collagen type II) were performed at each time point. As the pores became smaller, the value of the compressive strength of the scaffold was increased. The group of scaffolds with pore sizes of 90–250 µm showed better cell proliferation and ECM production. These results demonstrated that the compressive strength of the scaffold was improved while the scaffold had pore sizes in the range 90–250 µm and good cell interconnectivity. Suitable space in the scaffold for cell viability is a key factor for cell metabolism. Copyright © 2014 John Wiley & Sons, Ltd.     

Pore size regulates cell and tissue interactions with PLGA-CaP scaffolds used for bone engineering

A common subject in bone tissue engineering is the need for porous scaffolds to support cell and tissue interactions aiming at repairing bone tissue. As poly(lactide-co-glycolide)-calcium phosphate (PLGA-CaP) scaffolds can be manufactured with different pore sizes, the aim of this study was to evaluate the effect of pore diameter on osteoblastic cell responses and bone tissue formation. Scaffolds were prepared with 85% porosity, with pore diameters in the ranges 470-590, 590-850 and 850-1200 μm. Rat bone marrow stem cells differentiated into osteoblasts were cultured on the scaffolds for up to 10 days to evaluate cell growth, alkaline phosphatase (ALP) activity and the gene expression of the osteoblast markers RUNX2, OSX, COL, MSX2, ALP, OC and BSP by real-time PCR. Scaffolds were implanted in critical size rat calvarial defects for 2, 4, and 8 weeks for histomorphometric analysis. Cell growth and ALP activity were not affected by the pore size; however, there was an increase in the gene expression of osteoblastic markers with the increase in the pore sizes. At 2 weeks all scaffolds displayed a similar amount of bone and blood vessels formation. At 4 and 8 weeks much more bone formation and an increased number of blood vessels were observed in scaffolds with pores of 470-590 μm. These results show that PLGA-CaP is a promising biomaterial for bone engineering. However, ideally, combinations of larger (-1000 μm) and smaller (-500 μm) pores in a single scaffold would optimize cellular and tissue responses during bone healing.