Astrocytes are indispensable for central nervous system development and homeostasis.In response to injury and disease,astrocytes are integral to the immunological-and the,albeit limited,repair response.In this review,...Astrocytes are indispensable for central nervous system development and homeostasis.In response to injury and disease,astrocytes are integral to the immunological-and the,albeit limited,repair response.In this review,we will examine some of the functions reactive astrocytes play in the context of multiple sclerosis and related animal models.We will consider the heterogeneity or plasticity of astrocytes and the mechanisms by which they promote or mitigate demyelination.Finally,we will discuss a set of biomedical strategies that can stimulate astrocytes in their promyelinating response.展开更多
This review addresses two puzzling findings related to mutations in galactocerebrosidase （GALC） that cause Krabbe disease （KD）, a severe lysosomal storage disorder characterized by extensive myelin damage in child...This review addresses two puzzling findings related to mutations in galactocerebrosidase （GALC） that cause Krabbe disease （KD）, a severe lysosomal storage disorder characterized by extensive myelin damage in children with mutations in both GALC alleles. First, heterozygous carriers of KD-causing mutations, which include the biological parents of children with KD, exhibit increased risk for developing other diseases. Second, variants in the GALC locus increase the risk of developing multiple sclerosis （MS）, another disease characterized by extensive myelin damage. What explains these correlations？ In studies on cuprizone-induced myelin damage in heterozygous （GALC＋/–） mice carrying one copy of a mutation that causes KD-like disease, the extent of damage was similar in GALC＋/– and wild-type （WT） mice. In contrast, GALC＋/- mice had striking defects in repair of cuprizone-induced damage. We further found unexpected microglial defects in myelin debris clearance and in the ability to up-regulate the Trem2 microglial protein critical for debris uptake. These defects were rescued by exposure to a lysosomal re-acidifying drug discovered in our studies on KD, and which provides multiple clinically relevant benefits in the twitcher （GALC＋/–） mouse model of KD. Thus, heterozygous GALC mutations cause effects on biological function that may help to understand the increased disease risk in heterozygous carriers of such mutations and to understand why GALC variations increase the risk of MS. Our findings indicate that while some genetic risk factors may contribute to complex diseases by increasing the risk of tissue damage, others may do so by compromising tissue repair.展开更多
This literature review investigates the significant overlap between myelin-repair signaling pathways and pathways known to contribute to hallmark pathologies of Alzheimer’s disease(AD).We discuss previously investiga...This literature review investigates the significant overlap between myelin-repair signaling pathways and pathways known to contribute to hallmark pathologies of Alzheimer’s disease(AD).We discuss previously investigated therapeutic targets of amyloid,tau,and ApoE,as well as other potential therapeutic targets that have been empirically shown to contribute to both remyelination and progression of AD.Current evidence shows that there are multiple AD-relevant pathways which overlap significantly with remyelination and myelin repair through the encouragement of oligodendrocyte proliferation,maturation,and myelin production.There is a present need for a single,cohesive model of myelin homeostasis in AD.While determining a causative pathway is beyond the scope of this review,it may be possible to investigate the pathological overlap of myelin repair and AD through therapeutic approaches.展开更多
Chondroitin sulfate proteoglycan-4（CSPG4） is a surface component of two key cell types（oligodendrocyte progenitor cells（OPCs） and myeloid cells） present in lysolecithin-induced lesions in mouse spinal cord.Two t...Chondroitin sulfate proteoglycan-4（CSPG4） is a surface component of two key cell types（oligodendrocyte progenitor cells（OPCs） and myeloid cells） present in lysolecithin-induced lesions in mouse spinal cord.Two types of CSPG4 manipulations have been used to study the roles of these cells in myelin damage and repair：（1） OPC and myeloid-specific ablation of CSPG4,and（2） transplantation of enhanced green fluorescent protein（EGFP）-labeled progenitors to distinguish between bone marrow-derived macrophages and resident microglia.Ablation of CSPG4 in OPCs does not affect myelin damage,but decreases myelin repair,due to reduced proliferation of CSPG4-null OPCs that diminishes generation of mature oligodendrocytes for remyelination.Ablation of CSPG4 in myeloid cells greatly decreases recruitment of macrophages to spinal cord lesions,resulting in smaller initial lesions,but also in significantly diminished myelin repair.In the absence of macrophage recruitment,OPC proliferation is greatly impaired,again leading to decreased generation of myelinating oligodendrocytes.Macrophages may promote OPC proliferation via phagocytosis of myelin debris and/or secretion of factors that stimulate OPC mitosis.Microglia are not able to substitute for macrophages in promoting OPC proliferation.An additional feature of lesions in myeloid-specific CSPG4 null mice is the persistence of poorly-differentiated platelet-derived growth factor receptor α（PDGFRα） ＋ macrophages that may prolong damage.展开更多
Human umbilical mesenchymal stem cells from Wharton＇s jelly of the umbilical cord were induced to differentiate into oligodendrocyte precursor-like cells in vitro. Oligodendrocyte precursor cells were transplanted in...Human umbilical mesenchymal stem cells from Wharton＇s jelly of the umbilical cord were induced to differentiate into oligodendrocyte precursor-like cells in vitro. Oligodendrocyte precursor cells were transplanted into contused rat spinal cords. Immunofluorescence double staining indicated that transplanted cells survived in injured spinal cord, and differentiated into mature and immature oligodendrocyte precursor cells. Biotinylated dextran amine tracing results showed that cell transplantation promoted a higher density of the corticospinal tract in the central and caudal parts of the injured spinal cord. Luxol fast blue and toluidine blue staining showed that the volume of residual myelin was significantly increased at 1 and 2 mm rostral and caudal to the lesion epicenter after cell transplantation. Furthermore, immunofluorescence staining verified that the newly regenerated myelin sheath was derived from the central nervous system. Basso, Beattie and Bresnahan testing showed an evident behavioral recovery. These results suggest that human umbilical mesenchymal stem cell-derived oligodendrocyte precursor cells promote the regeneration of spinal axons and myelin sheaths.展开更多
Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types...Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types that are widely studied and most commonly used for cell transplantation to treat spinal cord injury, due to their intrinsic characteristics including the ability to secrete a variety of neurotrophic factors. This mini review summarizes the recent findings of endogenous Schwann cells after spinal cord injury and discusses their role in tissue repair and axonal regeneration. After spinal cord injury, numerous endogenous Schwann cells migrate into the lesion site from the nerve roots, involving in the construction of newly formed repaired tissue and axonal myelination. These invading Schwann cells also can move a long distance away from the injury site both rostrally and caudally. In addition, Schwann cells can be induced to migrate by minimal insults （such as scar ablation） within the spinal cord and integrate with astrocytes under certain circumstances. More importantly, the host Schwann cells can be induced to migrate into spinal cord by transplantation of different cell types, such as exogenous Schwann cells, olfactory ensheathing cells, and bone marrow-derived stromal stem cells. Migration of endogenous Schwann cells following spinal cord injury is a common natural phenomenon found both in animal and human, and the myelination by Schwann cells has been examined effective in signal conduction electrophysiologically. Therefore, if the inherent properties of endogenous Schwann cells could be developed and utilized, it would offer a new avenue for the restoration of injured spinal cord.展开更多
Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor la, a transcription factor, is of g...Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor la, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage There is little evidence of direct regulatory effects of hypoxia-inducible factor le on oligodendrocyte lineage gene-l. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor la or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor la and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor la, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor la levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor la can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.展开更多
目的研究尼莫地平对大鼠面神经损伤后髓鞘修复的作用及机制。方法 90只成年SD大鼠随机分成假手术组、单纯损伤组及药物干预组,采用定量损伤镊制作大鼠面神经主干卡压伤模型。对大鼠进行行为学及电生理学检测,取面神经进行苏木精-伊红(H...目的研究尼莫地平对大鼠面神经损伤后髓鞘修复的作用及机制。方法 90只成年SD大鼠随机分成假手术组、单纯损伤组及药物干预组,采用定量损伤镊制作大鼠面神经主干卡压伤模型。对大鼠进行行为学及电生理学检测,取面神经进行苏木精-伊红(H-E)染色、Luxol fast blue(LFB)髓鞘染色以及免疫组化法检测髓鞘碱性蛋白(MBP)和S-100β的表达。结果与单纯损伤组相比,药物干预组大鼠在损伤后20d的行为学评分显著改善,复合肌肉动作电位(CMAP)的潜伏期缩短,面神经组织结构恢复,髓鞘染色缺失区域减少,髓鞘碱性蛋白(MBP)及S-100β的抗原活性增强。结论尼莫地平可促进大鼠面神经损伤后的髓鞘修复,其机制可能与药物上调损伤后施万细胞S-100β的表达有关。展开更多
多发性硬化(MS)是以中枢神经系统炎性脱髓鞘为特征的自身免疫性疾病,神经功能障碍与髓鞘和轴索损伤有关。MS 动物模型研究认为:髓鞘修复是治疗 MS 极有前景的途径。中枢神经系统存在少突胶质细胞前体细胞(OPCs),在髓鞘修复和再生过程起...多发性硬化(MS)是以中枢神经系统炎性脱髓鞘为特征的自身免疫性疾病,神经功能障碍与髓鞘和轴索损伤有关。MS 动物模型研究认为:髓鞘修复是治疗 MS 极有前景的途径。中枢神经系统存在少突胶质细胞前体细胞(OPCs),在髓鞘修复和再生过程起关键作用。由于 MS 病人 OPC 分化受抑制,因此,在髓鞘再生过程中调控 OPCs 分化是髓鞘修复的重点。另外,移植外源性的髓鞘形成细胞促进髓鞘修复和神经再生,是修复 MS 脱髓鞘和轴索损伤的重要途径。展开更多
目的构建携带NGF及髓磷脂相关糖蛋白（myelin associated glycoprotein,MAG）基因序列的双基因共表达腺病毒（adenovirus expressing NGF and MAG,Ad-NGF-MAG）,探讨其在大鼠坐骨神经损伤修复中的作用。方法将NGF和MAG共同克隆至5型腺...目的构建携带NGF及髓磷脂相关糖蛋白（myelin associated glycoprotein,MAG）基因序列的双基因共表达腺病毒（adenovirus expressing NGF and MAG,Ad-NGF-MAG）,探讨其在大鼠坐骨神经损伤修复中的作用。方法将NGF和MAG共同克隆至5型腺病毒穿梭质粒p CA 13,并在HEK 293细胞中包装得到重组腺病毒Ad-NGF-MAG并测序鉴定。取雄性SD大鼠32只,体质量180~200 g;随机分成4组（n=8）：对照组（正常对照）、空病毒组（Ad组）、单独表达NGF组（Ad-NGF组）和共表达NGF、MAG组（Ad-NGF-MAG组）。Ad组、AdNGF组和Ad-NGF-MAG组大鼠制备右侧坐骨神经损伤模型后,分别于术侧腓肠肌注射空腺病毒、Ad-NGF及AdNGF-MAG（1×108 PFU）,隔天1次,共3次。对照组仅暴露右侧坐骨神经后关闭切口,术后对应时间点注射生理盐水10μL。术后31 d,分别行坐骨神经功能指数（sciatic nerve function index,SFI）、神经电生理检测;切取坐骨神经标本,行RT-PCR及Western blot检测NGF及MAG m RNA及蛋白表达水平,以及组织学观察。结果实验成功构建重组腺病毒Ad-NGF和Ad-NGF-MAG。32只大鼠术后均成活,切口Ⅰ期愈合。Ad-NGF-MAG组SFI、神经传导速度、诱发电位波幅、潜伏期均明显优于Ad-NGF组和Ad组,但未达对照组水平,比较差异均有统计学意义（P〈0.05）。Ad-NGF-MAG组内MAG m RNA和蛋白表达最高,NGF m RNA和蛋白表达高于对照组和Ad组,比较差异均有统计学意义（P〈0.05）。组织学观察显示,对照组神经连续性好,Ad组神经纤维层次混乱,Ad-NGF组神经纤维层次结构清晰,局部断端再生良好,但神经纤维结构紊乱;Ad-NGF-MAG组神经纤维生长有序,神经直径较Ad-NGF组粗,神经纤维结构良好。结论坐骨神经损伤后修复过程中,腺病毒介导NGF与MAG共表达,既可促进神经纤维生长,又可抑制神经异常分支形成,促进神经结构与功能的恢复。展开更多
基金supported by the Heart and Stroke Foundation and Ontario Institute of Regenerative Medicine (New Ideas Grant)Canada First Research Excellence Fund(Medicine by Design)+2 种基金the National Sciences and Engineering Research Councilthe Jurgen Manchot Foundationthe Christiane and Claudia Hempel Foundation for Clinical Stem Cell Research and the James and Elisabeth Cloppenburg,Peek and Cloppenburg Düsseldorf Stiftung (to PK)
文摘Astrocytes are indispensable for central nervous system development and homeostasis.In response to injury and disease,astrocytes are integral to the immunological-and the,albeit limited,repair response.In this review,we will examine some of the functions reactive astrocytes play in the context of multiple sclerosis and related animal models.We will consider the heterogeneity or plasticity of astrocytes and the mechanisms by which they promote or mitigate demyelination.Finally,we will discuss a set of biomedical strategies that can stimulate astrocytes in their promyelinating response.
基金supported by the following funding sources:National Institutes of Health,F31-NS078911,https://www.nih.gov(NSH)New York State Department of Health,NYS-DOH-C026877,http://www.stemcell.ny.gov(NSH)+4 种基金New York State Department of Health,NYS-DOH-C029557,http://www.stemcell.ny.gov(MN)New York State Department of Health,NYS-DOH-C026877,http://www.stemcell.ny.gov(CJF)Hunter’s Hope,http://www.huntershope.org/site/Page Server(MN)Children’s Neurobiological Solutions Foundation,http://pediatricbrainfoundation.org(MN)the Legacy of Angels,http://tloaf.org(MN)
文摘This review addresses two puzzling findings related to mutations in galactocerebrosidase （GALC） that cause Krabbe disease （KD）, a severe lysosomal storage disorder characterized by extensive myelin damage in children with mutations in both GALC alleles. First, heterozygous carriers of KD-causing mutations, which include the biological parents of children with KD, exhibit increased risk for developing other diseases. Second, variants in the GALC locus increase the risk of developing multiple sclerosis （MS）, another disease characterized by extensive myelin damage. What explains these correlations？ In studies on cuprizone-induced myelin damage in heterozygous （GALC＋/–） mice carrying one copy of a mutation that causes KD-like disease, the extent of damage was similar in GALC＋/– and wild-type （WT） mice. In contrast, GALC＋/- mice had striking defects in repair of cuprizone-induced damage. We further found unexpected microglial defects in myelin debris clearance and in the ability to up-regulate the Trem2 microglial protein critical for debris uptake. These defects were rescued by exposure to a lysosomal re-acidifying drug discovered in our studies on KD, and which provides multiple clinically relevant benefits in the twitcher （GALC＋/–） mouse model of KD. Thus, heterozygous GALC mutations cause effects on biological function that may help to understand the increased disease risk in heterozygous carriers of such mutations and to understand why GALC variations increase the risk of MS. Our findings indicate that while some genetic risk factors may contribute to complex diseases by increasing the risk of tissue damage, others may do so by compromising tissue repair.
基金Ms.Hirschfeld received support from multiple grants during the preparation of this manuscript:T32AG071444 and F31AG074700Dr.Saykin receives support from multiple NIH grants(P30 AG010133,P30 AG072976,R01 AG019771,R01 AG057739,U19 AG024904,R01 LM013463,R01 AG068193,T32 AG071444,and U01 AG068057 and U01 AG072177)Dr.Risacher receives support from NIH grants AG061788 and K01AG049050.Dr.Nho receives support from NIH grants R01 LM012535 and R03 AG054936.
文摘This literature review investigates the significant overlap between myelin-repair signaling pathways and pathways known to contribute to hallmark pathologies of Alzheimer’s disease(AD).We discuss previously investigated therapeutic targets of amyloid,tau,and ApoE,as well as other potential therapeutic targets that have been empirically shown to contribute to both remyelination and progression of AD.Current evidence shows that there are multiple AD-relevant pathways which overlap significantly with remyelination and myelin repair through the encouragement of oligodendrocyte proliferation,maturation,and myelin production.There is a present need for a single,cohesive model of myelin homeostasis in AD.While determining a causative pathway is beyond the scope of this review,it may be possible to investigate the pathological overlap of myelin repair and AD through therapeutic approaches.
基金supported by National Institutes of Health R01 CA095287(WBS)Sanford Burnham Prebys Medical Discovery Institute Lab Funding Initiative(WBS)
文摘Chondroitin sulfate proteoglycan-4（CSPG4） is a surface component of two key cell types（oligodendrocyte progenitor cells（OPCs） and myeloid cells） present in lysolecithin-induced lesions in mouse spinal cord.Two types of CSPG4 manipulations have been used to study the roles of these cells in myelin damage and repair：（1） OPC and myeloid-specific ablation of CSPG4,and（2） transplantation of enhanced green fluorescent protein（EGFP）-labeled progenitors to distinguish between bone marrow-derived macrophages and resident microglia.Ablation of CSPG4 in OPCs does not affect myelin damage,but decreases myelin repair,due to reduced proliferation of CSPG4-null OPCs that diminishes generation of mature oligodendrocytes for remyelination.Ablation of CSPG4 in myeloid cells greatly decreases recruitment of macrophages to spinal cord lesions,resulting in smaller initial lesions,but also in significantly diminished myelin repair.In the absence of macrophage recruitment,OPC proliferation is greatly impaired,again leading to decreased generation of myelinating oligodendrocytes.Macrophages may promote OPC proliferation via phagocytosis of myelin debris and/or secretion of factors that stimulate OPC mitosis.Microglia are not able to substitute for macrophages in promoting OPC proliferation.An additional feature of lesions in myeloid-specific CSPG4 null mice is the persistence of poorly-differentiated platelet-derived growth factor receptor α（PDGFRα） ＋ macrophages that may prolong damage.
基金supported by the National Natural Science Foundation of China, No. 81100916, 30400464,81271316the Postdoctoral Science Foundation of China,No. 201104901907
文摘Human umbilical mesenchymal stem cells from Wharton＇s jelly of the umbilical cord were induced to differentiate into oligodendrocyte precursor-like cells in vitro. Oligodendrocyte precursor cells were transplanted into contused rat spinal cords. Immunofluorescence double staining indicated that transplanted cells survived in injured spinal cord, and differentiated into mature and immature oligodendrocyte precursor cells. Biotinylated dextran amine tracing results showed that cell transplantation promoted a higher density of the corticospinal tract in the central and caudal parts of the injured spinal cord. Luxol fast blue and toluidine blue staining showed that the volume of residual myelin was significantly increased at 1 and 2 mm rostral and caudal to the lesion epicenter after cell transplantation. Furthermore, immunofluorescence staining verified that the newly regenerated myelin sheath was derived from the central nervous system. Basso, Beattie and Bresnahan testing showed an evident behavioral recovery. These results suggest that human umbilical mesenchymal stem cell-derived oligodendrocyte precursor cells promote the regeneration of spinal axons and myelin sheaths.
文摘Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types that are widely studied and most commonly used for cell transplantation to treat spinal cord injury, due to their intrinsic characteristics including the ability to secrete a variety of neurotrophic factors. This mini review summarizes the recent findings of endogenous Schwann cells after spinal cord injury and discusses their role in tissue repair and axonal regeneration. After spinal cord injury, numerous endogenous Schwann cells migrate into the lesion site from the nerve roots, involving in the construction of newly formed repaired tissue and axonal myelination. These invading Schwann cells also can move a long distance away from the injury site both rostrally and caudally. In addition, Schwann cells can be induced to migrate by minimal insults （such as scar ablation） within the spinal cord and integrate with astrocytes under certain circumstances. More importantly, the host Schwann cells can be induced to migrate into spinal cord by transplantation of different cell types, such as exogenous Schwann cells, olfactory ensheathing cells, and bone marrow-derived stromal stem cells. Migration of endogenous Schwann cells following spinal cord injury is a common natural phenomenon found both in animal and human, and the myelination by Schwann cells has been examined effective in signal conduction electrophysiologically. Therefore, if the inherent properties of endogenous Schwann cells could be developed and utilized, it would offer a new avenue for the restoration of injured spinal cord.
基金supported by the National Natural Science Foundation of China,No. 81241022the Natural Science Foundation of Beijing,No. 7072023,7122045
文摘Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor la, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage There is little evidence of direct regulatory effects of hypoxia-inducible factor le on oligodendrocyte lineage gene-l. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor la or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor la and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor la, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor la levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor la can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.
文摘目的研究尼莫地平对大鼠面神经损伤后髓鞘修复的作用及机制。方法 90只成年SD大鼠随机分成假手术组、单纯损伤组及药物干预组,采用定量损伤镊制作大鼠面神经主干卡压伤模型。对大鼠进行行为学及电生理学检测,取面神经进行苏木精-伊红(H-E)染色、Luxol fast blue(LFB)髓鞘染色以及免疫组化法检测髓鞘碱性蛋白(MBP)和S-100β的表达。结果与单纯损伤组相比,药物干预组大鼠在损伤后20d的行为学评分显著改善,复合肌肉动作电位(CMAP)的潜伏期缩短,面神经组织结构恢复,髓鞘染色缺失区域减少,髓鞘碱性蛋白(MBP)及S-100β的抗原活性增强。结论尼莫地平可促进大鼠面神经损伤后的髓鞘修复,其机制可能与药物上调损伤后施万细胞S-100β的表达有关。
文摘多发性硬化(MS)是以中枢神经系统炎性脱髓鞘为特征的自身免疫性疾病,神经功能障碍与髓鞘和轴索损伤有关。MS 动物模型研究认为:髓鞘修复是治疗 MS 极有前景的途径。中枢神经系统存在少突胶质细胞前体细胞(OPCs),在髓鞘修复和再生过程起关键作用。由于 MS 病人 OPC 分化受抑制,因此,在髓鞘再生过程中调控 OPCs 分化是髓鞘修复的重点。另外,移植外源性的髓鞘形成细胞促进髓鞘修复和神经再生,是修复 MS 脱髓鞘和轴索损伤的重要途径。
文摘目的构建携带NGF及髓磷脂相关糖蛋白（myelin associated glycoprotein,MAG）基因序列的双基因共表达腺病毒（adenovirus expressing NGF and MAG,Ad-NGF-MAG）,探讨其在大鼠坐骨神经损伤修复中的作用。方法将NGF和MAG共同克隆至5型腺病毒穿梭质粒p CA 13,并在HEK 293细胞中包装得到重组腺病毒Ad-NGF-MAG并测序鉴定。取雄性SD大鼠32只,体质量180~200 g;随机分成4组（n=8）：对照组（正常对照）、空病毒组（Ad组）、单独表达NGF组（Ad-NGF组）和共表达NGF、MAG组（Ad-NGF-MAG组）。Ad组、AdNGF组和Ad-NGF-MAG组大鼠制备右侧坐骨神经损伤模型后,分别于术侧腓肠肌注射空腺病毒、Ad-NGF及AdNGF-MAG（1×108 PFU）,隔天1次,共3次。对照组仅暴露右侧坐骨神经后关闭切口,术后对应时间点注射生理盐水10μL。术后31 d,分别行坐骨神经功能指数（sciatic nerve function index,SFI）、神经电生理检测;切取坐骨神经标本,行RT-PCR及Western blot检测NGF及MAG m RNA及蛋白表达水平,以及组织学观察。结果实验成功构建重组腺病毒Ad-NGF和Ad-NGF-MAG。32只大鼠术后均成活,切口Ⅰ期愈合。Ad-NGF-MAG组SFI、神经传导速度、诱发电位波幅、潜伏期均明显优于Ad-NGF组和Ad组,但未达对照组水平,比较差异均有统计学意义（P〈0.05）。Ad-NGF-MAG组内MAG m RNA和蛋白表达最高,NGF m RNA和蛋白表达高于对照组和Ad组,比较差异均有统计学意义（P〈0.05）。组织学观察显示,对照组神经连续性好,Ad组神经纤维层次混乱,Ad-NGF组神经纤维层次结构清晰,局部断端再生良好,但神经纤维结构紊乱;Ad-NGF-MAG组神经纤维生长有序,神经直径较Ad-NGF组粗,神经纤维结构良好。结论坐骨神经损伤后修复过程中,腺病毒介导NGF与MAG共表达,既可促进神经纤维生长,又可抑制神经异常分支形成,促进神经结构与功能的恢复。
