骨髓间充质干细胞可减轻脑卒中缺血周围皮质小胶质细胞过度激活引起的脑损伤

背景:骨髓间充质干细胞移植治疗缺血性脑卒中取得了较好效果,但其作用机制仍需进行深入研究。目的:探讨骨髓间充质干细胞对缺血周围皮质过度活化的小胶质细胞损伤的影响。方法:将30只8周龄的SD大鼠分为假手术组、模型组、移植组。模型组和移植组采用栓线法阻断大脑中动脉,建立大鼠缺血性脑卒中模型,术后将第3代骨髓间充质干细胞注入到移植组大鼠腹腔内,模型组和假手术组大鼠腹腔内注射相同量的DMEM培养液,各组均隔天注射1次,共持续14 d。术后第7,14天,通过BBB法来评估各组大鼠的运动功能,术后15 d取大鼠脑梗死灶周围皮质并应用免疫组织化学染色法、蛋白印迹法检测活性小胶质细胞标志物Ox-42以及促炎因子肿瘤坏死因子α、白细胞介素6、白细胞介素1β的表达。结果与结论:与假手术组相比,模型组小胶质细胞激活的Ox-42和肿瘤坏死因子α、白细胞介素6、白细胞介素1β表达水平较高,移植组上述指标表达水平较低。与模型组相比,移植组BBB评分明显提高,肢体运动功能有所改善。结果表明,骨髓间充质干细胞抑制梗死灶周围小胶质细胞的过度活化,降低了炎性细胞因子的表达,从而在一定程度上保护了大脑皮质免受伤害,促进了运动...     

骨髓间充质干细胞移植脊髓损伤小鼠运动功能的恢复

背景：研究证实,移植的骨髓间充质干细胞可被定向诱导分化为神经细胞,重建神经环路,促进轴突再生,恢复脊髓功能。 目的：进一步验证骨髓间充质干细胞在脊髓损伤修复中的作用。 方法：C57BL/6小鼠40只随机分为4组,假手术组不打击脊髓;其余小鼠采用重物撞击法建立脊髓损伤模型。损伤后的第7天,治疗组用微量注射器,经眶静脉丛注入骨髓间充质干细胞悬液;对照组注入等量 DMEM培养基;模型组不做处理。通过苏木精-伊红染色法判断脊髓损伤程度。通过免疫细胞化学法鉴定骨髓间充质干细胞分化形成的神经细胞。通过荧光显微镜观察移植细胞生长状态;通过改良Tarlov评分法评价小鼠运动功能恢复程度。 结果与结论：骨髓间充质干细胞诱导分化7 d后的细胞呈NF和神经胶质纤维酸性蛋白阳性表达。模型组小鼠双下肢呈瘫痪状态,假手术组行动正常(P < 0.01)。细胞移植后2周,治疗组小鼠运动功能缺失症状逐渐恢复,对照组小鼠恢复不明显 (P < 0.05);细胞移植4周后,细胞移植组小鼠Tarlov评分与假手术组相比差异无显著性意义(P > 0.05)。说明骨髓间充质干细胞移植可提高脊髓损伤小鼠的运动能力。     

异体骨髓间充质干细胞移植治疗大鼠脊髓损伤

背景:脊髓损伤的修复目前尚无良好的治疗手段,细胞移植能促进神经轴突再生及脊髓功能恢复,为治疗脊髓损伤提供了可能,但因脊髓损伤模型及移植方式不同,其治疗效果并不相同。目的:验证异体骨髓间充质干细胞移植对大鼠脊髓损伤的治疗作用。方法:全骨髓贴壁法分离大鼠骨髓间充质干细胞。健康SD大鼠随机分为3组,细胞移植组、对照组和假手术组。细胞移植组和对照组采用改良Allen重物打击法制造大鼠脊髓损伤模型,假手术组仅暴露脊髓。术后4周,每周进行运动功能评分ELISA检测脊髓损伤组织中脑源性神经营养因子、神经生长因子表达;免疫荧光染色检测脊髓组织中NF200和胶质纤维酸性蛋白表达。结果与结论:与对照组比较,细胞移植组大鼠运动功能明显改善,脊髓组织中脑源性神经营养因子、神经生长因子蛋白含量明显增高(P0.05);移植组大鼠脊髓囊腔较小,NF200表达明显增加,胶质纤维酸性蛋白表达减少。提示异体骨髓间充质干细胞移植能增加损伤脊髓神经生长因子含量,抑制胶质瘢痕形成,促进神经轴突再生,改善大鼠脊髓损伤后运动功能恢复。     

以脑源性神经营养因子等干预视神经损伤大鼠视神经拉伸力学的特性分析

以拉伸力学性能指标研判以人脐血干细胞、脑源性神经营养因子干预视神经损伤动物模型的效果。以钳夹法制备视神经损伤大鼠模型,于视神经损伤大鼠模型造模7 d后,分别以人脐血干细胞、脑源性神经营养因子进行干预治疗,对各组大鼠于造模30 d后取出眶内段视神经进行组织形态观察和拉伸实验。视神经组织形态观察结果表明,视神经损伤动物模型以BDNF干预组一部分神经纤维排列较整齐,胶质细胞可见少量细胞空泡,一部分细胞核排列不规则,但视神经轴突直径改变不明显。视神经损伤动物模型以h UCBSC干预组视神经纤维排列较密集,胶质细胞核增多,多数轴突形态正常。各组动物视神经拉伸实验结果表明,视神经损伤动物模型组视神经的最大载荷、最大应力、最大应变、弹性限度载荷、弹性限度应力小于视神经损伤模型以h UCBSC、以BDNF干预组,差异显著(P0.05),视神经损伤模型以BDNF干预组的最大载荷、最大应力、最大应变、弹性限度载荷、弹性限度应力小于以h UCBSC干预组,差异显著(P0.05)。视神经损伤动物模型以BDNF和以h UCBSC干预后动物视神经的拉伸力学性能指标得到了显著提高。提示,视神经损伤模型大鼠通过BDNF、h UCBSC干预治疗后,具有明显的疗效。     

骨髓间充质干细胞移植脑出血模型大鼠血肿周围轴突生长抑制因子MAG及OMgp的表达*

背景：中枢神经系统损伤后轴突再生困难与损伤灶周围高表达轴突生长抑制因子Nogo-A、MAG、OMgp有关。 目的：观察骨髓间充质干细胞移植对脑出血模型大鼠神经功能恢复及血肿周围轴突生长抑制因子MAG、OMgp表达的影响。 方法：全骨髓贴壁法分离培养大鼠骨髓间充质干细胞,使用立体定向纹状体注入胶原酶法制作大鼠脑出血模型。SD大鼠分为假手术组、脑出血模型组及骨髓间充质干细胞干预组,骨髓间充质干细胞干预组于造模后24 h经尾静脉注射1×107的骨髓间充质干细胞悬液,各组于造模后1,3,7,14 d进行神经功能评分,并在各时间点处死大鼠行免疫组织化学法检测MAG、OMgp的表达情况。 结果与结论：假手术组术后各个时间点均未见明显神经功能缺损;脑出血模型组神经功能缺损术后1 d时即达高峰,14 d时有进一步的恢复;骨髓间充质干细胞干预组神经功能评分在3,7,14 d各个时间点均较模型组明显降低(P < 0.05)。各个时间点模型组及骨髓间充质干细胞干预组血肿周围神经元及胶质细胞MAG、OMgp的表达均较假手术组明显升高,骨髓间充质干细胞干预组较模型组表达均有降低(P < 0.05)。提示骨髓间充质干细胞移植可明显促进大鼠脑出血后神经功能的恢复,其机制可能与下调血肿周围MAG、OMgp的表达有关。      

骨髓间充质干细胞静脉移植脊髓损伤大鼠肿瘤坏死因子α及 白细胞介素1β的表达

背景：研究认为间充质干细胞的营养支持在脊髓损伤治疗中起了主要作用,其同损伤宿主神经组织间的相互作用可导致一些不利于损伤修复的炎症因子表达减少。 目的：观察大鼠骨髓间充质干细胞静脉注射移植对脊髓损伤后肿瘤坏死因子α、白细胞介素1β 表达的影响。 方法：运用改良Allen法制备大鼠T10脊髓外伤性截瘫模型,随机分为对照组和骨髓间充质干细胞移植组,设未损伤脊髓的假手术组做对照。骨髓间充质干细胞移植组、假手术组均接受大鼠骨髓间充质干细胞静脉注射移植,对照组静脉注射等量PBS。 结果与结论：对照组和骨髓间充质干细胞移植组损伤脊髓肿瘤坏死因子α、白细胞介素1β蛋白表达较假手术组有明显增加(P < 0.05);骨髓间充质干细胞移植组与对照组比较, 肿瘤坏死因子α、白细胞介素1β蛋白表达受到明显抑制(P < 0.05)。提示大鼠骨髓间充质干细胞静脉移植后能使损伤脊髓局部的肿瘤坏死因子α、白细胞介素1β表达程度降低。这可能是改变脊髓损伤区的微环境,减少脊髓继发性损伤,促进损伤大鼠运动功能恢复的机制之一。     

骨髓间充质干细胞移植治疗失神经肌萎缩

背景:外科显微镜手术和一些辅助治疗方法均无法通过修复损伤的神经细胞来有效延缓或治疗失神经肌萎缩。研究发现骨髓间充质干细胞具有定向分化潜能,并且在一定环境因素下能对损伤的组织进行修复,由此推测其可以对失神经萎缩肌肉起到一定的修复作用。目的:探讨移植骨髓间充质干细胞是否能够减轻和延缓失神经肌肉组织萎缩。方法:分离培养SD大鼠骨髓间充质干细胞,取第3代骨髓间充质干细胞经BrdU标记后用于移植治疗。将30只SD大鼠分为3组,每组10只,对每只大鼠左后肢进行手术。假手术组只暴露坐骨神经主干,不钳夹神经,移植治疗组、模型对照组钳夹坐骨神经主干后,向其支配的腓肠肌注射骨髓间充质干细胞悬液和不含胎牛血清的DMEM培养液。骨髓间充质干细胞移植后1,2周,采用BBB评分评价各组大鼠左后肢运动功能;骨髓间充质干细胞移植后14 d,取腓肠肌组织进行苏木精-伊红染色和BrdU免疫组化染色。结果与结论:第3代骨髓间充质干细胞BrdU标记为阳性;标记的骨髓间充质干细胞能在移植治疗组失神经损伤的肌肉组织中存活并起修复作用;相对于模型对照组,移植治疗组失神经肌纤维由相互融合重新恢复规整。结果表明移植骨髓间充质干细胞能够减轻和延缓失神经肌肉组织萎缩。     

骨髓间充质干细胞尾静脉移植脊髓损伤大鼠脑源性神经营养因子及神经生长因子的表达

背景：骨髓间充质干细胞移植对脊髓损伤有治疗作用,但其机制尚不完全清楚。 目的：应用免疫组织化学方法观察骨髓间充质干细胞静脉移植损伤脊髓局部脑源性神经营养因子及神经生长因子的表达,分析骨髓间充质干细胞移植治疗大鼠脊髓损伤的作用途径。 方法：运用改良Allen法制备T10脊髓外伤性截瘫大鼠模型,假手术组6只,脊髓损伤组24只随机分为对照组和骨髓间充质干细胞移植组。骨髓间充质干细胞移植组、假手术组接受骨髓间充质干细胞单细胞悬液1 mL(1×10⁶ cells)自大鼠尾静脉缓慢注射移植,对照组静脉注射PBS 1 mL。 结果与结论：脊髓损伤后损伤局部的脑源性神经营养因子、神经生长因子表达增加,骨髓间充质干细胞静脉注射移植后能促进脊髓损伤局部脑源性神经营养因子、神经生长因子更进一步的表达,这可能是促进神经结构及神经功能恢复的因素之一。     

控释胶质细胞源性神经营养因子与骨髓间充质干细胞源神经元样细胞移植可减少脊髓损伤后空洞形成

背景：前期研究发现控释胶质细胞源性神经营养因子与骨髓间充质干细胞源神经元样细胞移植可以有效地促进猕猴脊髓损伤后运动功能的恢复。 目的：验证控释胶质细胞源性神经营养因子联合骨髓间充质干细胞源神经元样细胞移植对猴脊髓损伤后组织结构的保护作用是否优于单纯细胞移植。 方法：将急性重度脊髓损伤模型恒河猴分为3组,联合移植组采用控释神经营养因子+神经元样细胞联合移植,单纯细胞移植组给予神经元样细胞移植,对照组给予磷酸盐缓冲液。制备脊髓组织石蜡标本,苏木精-伊红染色后显微镜下观察空洞形成情况,并应用图像分析系统计算空洞面积。 结果与结论：对照组脊髓结构严重破坏,空洞面积大、累及范围广;单纯细胞移植组脊髓结构保存较好,有小面积空洞,偶有较大空洞形成;联合移植组脊髓结构保存最好,仅存在小面积空洞。组间两两比较差异有显著意义(P < 0.01)。提示与单纯神经元样细胞移植比较,控释胶质细胞源性神经营养因子联合骨髓间充质干细胞源性神经元样细胞移植对脊髓损伤后组织结构的保护作用更佳,可以在更大程度上减少脊髓空洞的形成可能是其作用机制之一。     

控释神经营养因子与细胞移植减少损伤脊髓的胶质瘢痕

背景：前期研究发现控释胶质细胞源性神经营养因子与骨髓间充质干细胞源神经元样细胞联合移植可有效促进猕猴脊髓损伤后运动功能和感觉功能的恢复。 目的：观察控释胶质细胞源性神经营养因子联合骨髓间充质干细胞源神经元样细胞移植抑制猴脊髓损伤后胶质瘢痕形成的作用是否优于单纯细胞移植。 方法：取12只恒河猴,采用改良Allen氏法制作急性重度脊髓损伤模型,随机数字表法分为3组,实验组以控释胶质细胞源性神经营养因子联合自体骨髓间充质干细胞源神经元样细胞移植修复,对照组以自体骨髓间充质干细胞源神经元样细胞移植修复,空白对照组以磷酸盐缓冲液修复。修复后5个月,取出脊髓组织制成石蜡标本,应用免疫组织化学染色显示胶质瘢痕的形态特征、构成特点及瘢痕中神经纤维的再生情况,检测胶质瘢痕面积及胶质纤维酸性蛋白染色的平均吸光度值。 结果与结论：脊髓损伤部位胶质瘢痕由混合性增生的星形胶质细胞和组织细胞构成。空白对照组脊髓胶质瘢痕累及范围广,星形胶质细胞增生显著,神经丝蛋白免疫组织化学染色阴性,胶质瘢痕面积、胶质纤维酸性蛋白染色平均吸光度值高于实验组与对照组(P < 0.05);实验组、对照组脊髓胶质瘢痕累及范围较局限,神经丝蛋白免疫组织化学染色显示有少量神经纤维通过瘢痕区,并且实验组胶质瘢痕面积、胶质纤维酸性蛋白染色平均吸光度值低于对照组(P < 0.05)。结果表明,控释胶质细胞源性神经营养因子联合骨髓间充质干细胞源性神经元样细胞移植可更强抑制脊髓损伤后胶质瘢痕的形成。     

The role of macrophages in optic nerve regeneration

Following injury to the nervous system, the activation of macrophages, microglia, and T-cells profoundly affects the ability of neurons to survive and to regenerate damaged axons. The primary visual pathway provides a well-defined model system for investigating the interactions between the immune system and the nervous system after neural injury. Following damage to the optic nerve in mice and rats, retinal ganglion cells, the projection neurons of the eye, normally fail to regenerate their axons and soon begin to die. Induction of an inflammatory response in the vitreous strongly enhances the survival of retinal ganglion cells and enables these cells to regenerate lengthy axons beyond the injury site. T cells modulate this response, whereas microglia are thought to contribute to the loss of retinal ganglion cells in this model and in certain ocular diseases. This review discusses the complex and sometimes paradoxical actions of blood-borne macrophages, resident microglia, and T-cells in determining the outcome of injury in the primary visual pathway.     

过表达Shootin1的骨髓间充质干细胞移植治疗脊髓损伤

BACKGROUND:Genetic modification by Shootin1 aims to effectively improve neural differentiation of bone marrow mesechymal stem cells (BMSCs) in the injured spinal cord, thereby promoting functional recovery from spinal cord injury after cell transplantation. OBJECTIVE:To explore the nerve regeneration ability of transplanted BMSCs overexpressing Shootin1 in rats with spinal cord injury. METHODS:BMSCs were transfected using adenovirus-Shootin1 for 48 hours. Then, immunofluorescence staining was used to detect Nestin and NeuN expression levels in the transfected cells under in vitro neuronal induction and differentiation. Animal models of spinal cord injury were made in rats using modified Allen’s method. Thirty minutes later, Shootin1-transfected BMSCs and non-transfected BMSCs were respectively injected into the subarachnoid space of the rats in the transfection and non-transfection groups, respectively. Rats in the model group were given no treatment. Five weeks after modeling, spinal cord samples were taken from each rat to make frozen sections for detection of nerve related markers RESULTS AND CONCLUSION:After 48-hour adenoviral transfection, Shootin1 expression was successfully detected in BMSCs. After 7-day in vitro induction, the cell morphology in the three groups varied, and there was no significant difference in the expression of Nestin and NeuN between the transfection and non-transfection groups. Basso, Beattie and Bresnahan scores were higher in the two cell transplantation groups than the model group. Increased expression levels of Nestin, NeuN, GFAP, MAP-2, ChAT and SYN were observed in both two cell transplantation groups, indicating a strengthened ability of nerve regeneration. Our experimental findings further confirm that BMSCs transplantation for spinal cord injury has achieved good outcomes, and Shootin1 protein plays a certain role in nerve regeneration and functional recovery after spinal cord injury. However, Shootin1 overexpression shows no obvious additional effects in combination with BMSCs transplantation, and further studies on the optimization of BMSCs transplantation for spinal cord injury are necessary.     

Prostaglandin E2 changes in the retina and optic nerve of an eye with injured optic nerve.

Changes in arachidonic acid metabolism were studied in the optic nerve, the chorioretina, and in the vitreous following crush injury to the optic nerve of rats. Crush injury led to: (i) a 3.9-fold increase in optic nerve prostaglandin type E2 in vitro production which peaked on day 5 and was followed by a gradual decline, but was still significantly higher than baseline levels by day 12; (ii) a two-fold increase in the chorioretina prostaglandin type E2 in vitro production which peaked on day 1, and resumed baseline levels by day 3; (iii) a 3.5-fold increase in vitreous prostaglandin type E2 levels on day 1 which remained at 1.5-2 times higher than baseline levels for the rest of the study period (12 days). The findings indicate that the pattern of changes in prostaglandin type E2 production by the optic nerve (consisting mostly of white matter) is different from that described for injured brain tissues. The prolonged accumulation of vitreal prostaglandin type E2 in eyes with damaged optic nerve may lead to undesirable effects on the retina beyond those directly manifested in the retina by altered axonal flow in the injured optic nerve.     

Peripheral nerve explants grafted into the vitreous body of the eye promote the regeneration of retinal ganglion cell axons severed in the optic nerve

Summary We have conducted experiments in the adult rat visual system to assess the relative importance of an absence of trophic factors versus the presence of putative growth inhibitory molecules for the failure of regeneration of CNS axons after injury. The experiments comprised three groups of animals in which all optic nerves were crushed intra-orbitally: an optic nerve crush group had a sham implant-operation on the eye; the other two groups had peripheral nerve tissue introduced into the vitreous body; in an acellular peripheral nerve group, a frozen/thawed teased sciatic nerve segment was grafted, and in a cellular peripheral nerve group, a predegenerate teased segment of sciatic nerve was implanted. The rats were left for 20 days and their optic nerves and retinae prepared for immunohistochemical examination of both the reaction to injury of axons and glia in the nerve and also the viability of Schwann cells in the grafts. Anterograde axon tracing with rhodamine-B provided unequivocal qualitative evidence of regeneration in each group, and retrograde HRP tracing gave a measure of the numbers of axons growing across the lesion by counting HRP filled retinal ganglion cells in retinal whole mounts after HRP injection into the optic nerve distal to the lesion. No fibres crossed the lesion in the optic nerve crush group and dense scar tissue was formed in the wound site. GAP-43-positive and rhodamine-B filled axons in the acellular peripheral nerve and cellular peripheral nerve groups traversed the lesion and grew distally. There were greater numbers of regenerating fibres in the cellular peripheral nerve compared to the acellular peripheral nerve group. In the former, 0.6–10% of the retinal ganglion cell population regenerated axons at least 3–4 mm into the distal segment. In both the acellular peripheral nerve and cellular peripheral nerve groups, no basal lamina was deposited in the wound. Thus, although astrocyte processes were stacked around the lesion edge, a glia limitans was not formed. These observations suggest that regenerating fibres may interfere with scarring. Viable Schwann cells were found in the vitreal grafts in the cellular peripheral nerve group only, supporting the proposition that Schwann cell derived trophic molecules secreted into the vitreous stimulated retinal ganglion cell axon growth in the severed optic nerve. The regenerative response of acellular peripheral nerve-transplanted animals was probably promoted by residual amounts of these molecules present in the transplants after freezing and thawing. In the optic nerves of all groups the astrocyte, microglia and macrophage reactions were similar. Moreover, oligodendrocytes and myelin debris were also uniformly distributed throughout all nerves. Our results suggest either that none of the above elements inhibit CNS regeneration after perineuronal neurotrophin delivery, or that the latter, in addition to mobilising and maintaining regeneration, also down regulates the expression of axonal growth cone-located receptors, which normally mediate growth arrest by engaging putative growth inhibitory molecules of the CNS neuropil.     

A direct projection from the nucleus oculomotorius to the retina in rats

The centrifugal projection to the eye has been studied in rats with anterograde and retrograde tracing techniques. As a retrograde tracer Nuclear Yellow (NY) was used. Following NY injections into the vitreous body of the eye, labeled neurons were exclusively found bilaterally in nucleus oculomotorius. The course and termination site of the retinopetal fibers were studied with the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L). Iontophoretic injections of PHA-L in nucleus oculomotorius resulted in labeling of retinopetal fibers which reach the eye via the optic tract and optic nerve. Preterminal arborizations were found in the inner nuclear layer of the retina. In addition, labeled fibers have been observed which seem to terminate within the optic tract and optic nerve. It is suggested that the projection from the nucleus oculomotorius to the retina constitutes a link in the multisynaptic efferent pathway from the visual cortex to the eye, by which the visual cortex can influence the functioning of the retina.     

SD大鼠视网膜中央动脉的应用解剖学研究

目的　为建立稳定可靠的视神经损伤动物模型寻求解剖学依据。 方法　用红色乳胶灌注技术显示正常SD大鼠视网膜中央动脉的来源、分支、分布及其与视神经的关系,并采用体视显微镜摄片测量;明胶墨汁灌注技术显示距眼球后极2.0 mm或6.0 mm处横断视神经后视网膜的血供。 结果　视网膜中央动脉及其分支在视神经鞘内始终与视神经干伴行,视网膜中央动脉起始部到眼球后极的距离为(5.784±0.054)mm;距离眼球后极6.0 mm处鞘内视神经横断组大鼠视网膜单位面积血管数目高于其他部位横断组。 结论　在制备视神经损伤SD大鼠模型时,损伤视神经应在鞘内进行,损伤部位距眼球后极　6.0 mm最佳。     

骨髓间充质干细胞移植治疗急性一氧化碳中毒迟发性脑病大鼠*☆

背景：国内多采用药物治疗和高压氧治疗一氧化碳中毒迟发性脑病,但存在疗程长,见效慢,花费高等问题。 目的：观察骨髓间充质干细胞移植治疗一氧化碳中毒迟发性脑病前后神经元及细胞凋亡的变化。 方法：将SD大鼠抽签随机分为假手术组、对照组与干细胞移植组。制作一氧化碳中毒迟发性脑病模型后,干细胞移植组在造模后第0,3,6,12,24,72小时及1周时脑内注射同种异体骨髓间充质干细胞,对照组不进行细胞移植;假手术组扎闭颈外动脉,用PBS代替细胞悬液。 结果与结论：造模后3,6,12,24 h干细胞移植组脑内神经元核心抗原表达明显高于对照组与假手术组(P < 0.01),干细胞移植各组脑内神经元核心抗原表达无明显差异(P > 0.05)。造模后0,3,6 h干细胞移植组脑内细胞凋亡平均吸光度值明显低于对照组与假手术组及其他干细胞移植组(P < 0.05),且移植后第1周明显低于第2,3,4周(P < 0.05)。提示在一氧化碳中毒迟发性脑病大鼠体内移植间充质干细胞可以增加成熟神经元数量,其机制与减少细胞凋亡有关;移植的最佳时机为发病后0~24 h之间,细胞移植后的积极作用在第1周最明显。关键词：一氧化碳中毒迟发性脑病;骨髓间充质干细胞;神经元;凋亡;干细胞移植 doi:10.3969/j.issn.1673-8225.2012.19.025     

毛囊神经干细胞促进受损大鼠视神经大胶质细胞去分化

目的 培养毛囊神经干细胞,研究其对受损视神经大胶质细胞去分化的影响。 方法 取约90g雄性SD大鼠触须垫毛囊隆突区贴块,无血清培养或经15%胎牛血清诱导培养毛囊隆突区细胞,用免疫荧光细胞化学和PCR鉴定;以含增强型绿色荧光蛋白的腺相关病毒（rAAV2EGFP）稳定转染该细胞。成年雄性SD大鼠54只,分为正常对照组、损伤组、移植组,移植组为视神经损伤后移植上述毛囊神经干细胞。转染细胞移植组术后7d、14d、30d,取视神经荧光显微镜下观察;损伤组和未转染细胞移植组术后7d取术侧视神经行Affymetrix基因芯片及实时荧光定量PCR检测,术后7d、14d取术侧视神经行HE、免疫组织化学检测。 结果 成功培养出神经前体细胞标记分子阳性的毛囊神经干细胞,诱导后该细胞可表达成熟神经细胞标记分子。毛囊神经干细胞移植到受损视神经30 d后,仍能存活和迁移。与损伤组相比,移植组差异表达基因有240条,其中一些与去分化相关,如干细胞、凋亡、增殖、信号转导、转录、分化发育、细胞黏附等相关基因,实时荧光定量PCR与基因芯片结果基本相符。移植组视神经远侧段细胞数较损伤组明显增多,巢蛋白、髓鞘碱性蛋白(MBP)、细胞外信号调节激酶1/2(ERK1/2)表达增加,胶质纤维酸性蛋白(GFAP)表达减少,且视神经近侧段神经丝(NF)表达增加。 结论 毛囊神经干细胞通过调节受损视神经中的一些基因表达,促进了其大胶质细胞去分化并向有利于神经再生方向变化。     

Microglia in tadpoles ofXenopus laevis: Normal distribution and the response to optic nerve injury

Summary We have studied the distribution of microglia in normalXenopus tadpoles and after an optic nerve lesion, using a monoclonal antibody (5F4) raised againstXenopus retinas of which the optic nerves had been cut 10 days previously. The antibody 5F4 selectively recognizes macrophages and microglia inXenopus. In normal animals microglia are sparsely but widely distributed throughout the retina, optic nerve, diencephalon and mesencephalon (other regions were not examined). After crush or cut of an optic nerve, or eye removal, there occurs an extensive microglial response along the affected optic pathway. Within 18 h an increase in the number of microglial cells in the optic tract and tectum can be detected. This response increases to peak at around 5 days after the lesion. At this time the nerve distal to the lesion contains many microglial cells; the entire optic tract is outlined by microglia, extended along the degenerating fibres; and the affected tectum shows a heavy concentration of microglia. This microglial response thereafter decreases and has mostly gone by 34 days. We conclude that the microglial response to optic nerve injury inXenopus tadpoles starts early, peaks just before the regenerating optic nerve axons enter the brain, and is much diminished by the time the retinotectal projection is re-established. The timing is such that the microglial response could play a major role in facilitating regeneration.