Puerarin accelerates neural regeneration after sciatic nerve injury

Puerarin is a natural isoflavone isolated from plants of the genus Pueraria and functions as a protector against cerebral ischemia. We hypothesized that puerarin can be involved in the repair of peripheral nerve injuries. To test this hypothesis, doses of 10, 5, or 2.5 mg/kg per day puerarin(8-(β-D-Glucopyranosyl-7-hydroxy-3-(4-hydroxyphenyl)-4H-1-benzopyran-4-one) were injected intraperitoneally into mouse models of sciatic nerve injury. Puerarin at the middle and high doses significantly up-regulated the expression of growth-associated protein 43 in the L4–6 segments of the spinal cord from mice at 1, 2, and 4 weeks after modeling, and reduced the atrophy of the triceps surae on the affected side and promoted the regeneration of nerve fibers of the damaged spinal cord at 8 weeks after injury. We conclude that puerarin exerts an ongoing role to activate growth-associated protein 43 in the corresponding segment of the spinal cord after sciatic nerve injury, thus contributing to neural regeneration after sciatic nerve injuries.     

自体肋间神经联合酸性成纤维细胞生长因子移植治疗高位脊髓损伤

背景：酸性成纤维细胞生长因子具有调节细胞增殖、移行、分化和生存的作用,也可以下调已知轴突再生的抑制因子如蛋白聚糖等,帮助轴突克服这些抑制因子,对神经纤维再生有重要作用。 目的：观察酸性成纤维细胞生长因子联合周围神经移植治疗大鼠高位脊髓损伤的可行性及效果。 方法：健康成年雌性SD大鼠108只随机抽签法分为自体神经组、自体神经联合生长因子组、高位脊髓横断组。咬除大鼠T8~10棘突、椎板,显露硬膜囊,水平切断高位脊髓并切除3 mm,显微镜下确认无神经纤维相连。自体神经组、自体神经联合生长因子组取双侧第8~10对肋间神经各2 cm,将肋间神经交叉移植入高位脊髓缺损处(近端白质与远端灰质、远端白质与近端灰质),分别以纤维蛋白凝胶、含有酸性成纤维细胞生长因子的纤维蛋白凝胶固定植入的肋间神经,缝合硬膜。高位脊髓横断组断端间旷置。术后90 d,行体感诱发电位及运动诱发电位检测观察神经电生理恢复情况。术后76 d,生物素葡聚糖胺顺行神经示踪观察运动传导束恢复情况。术后60 d,后肢BBB运动功能评分观察肢体运动恢复情况。 结果与结论：高位脊髓横断组大鼠均未引出体感及运动诱发电位波形。自体神经组、自体神经联合生长因子组均可引出体感及运动诱发电位,自体神经联合生长因子组体感诱发电位及运动诱发电位的平均潜伏期和波幅、BBB评分均明显优自体神经组(P < 0.01)。自体神经组和自体神经联合生长因子组在损伤区有较多生物素葡聚糖胺标记阳性神经纤维通过,明显多于高位脊髓横断组(P < 0.01),自体神经联合生长因子组多于自体神经组(P < 0.01)。提示自体周围神经移植酸性成纤维细胞生长因子能更好地恢复高位脊髓损伤后大鼠肢体运动功能。     

Changes in urinary bladder neurotrophic factor mRNA and NGF protein following urinary bladder dysfunction

Spinal cord injury and cyclophosphamide-induced cystitis dramatically alter lower urinary tract function and produce neurochemical, electrophysiological, and anatomical changes that may contribute to reorganization of the micturition reflex. Mechanisms underlying this neural plasticity may involve alterations in neurotrophic factors in the urinary bladder. These studies have determined neurotrophic factors in the urinary bladder that may contribute to reorganization of the micturition reflex following cystitis or spinal cord injury. A ribonuclease protection assay was used to measure changes in urinary bladder neurotrophic factor mRNA (betaNGF, BDNF, GDNF, CNTF, NT-3, and NT-4) following spinal cord injury (acute/chronic) or cyclophosphamide-induced cystitis (acute/chronic). The correlation between urinary bladder nerve growth factor mRNA and nerve growth factor protein expression was also determined. Each experimental paradigm resulted in significant (P 相似文献   

GAP-43 mRNA in Rat Spinal Cord and Dorsal Root Ganglia Neurons: Developmental Changes and Re-expression Following Peripheral Nerve Injury

The expression of growth-associated protein GAP-43 mRNA in spinal cord and dorsal root ganglion (DRG) neurons has been studied using an enzyme linked in situ hybridization technique in neonatal and adult rats. High levels of GAP-43 mRNA are present at birth in the majority of spinal cord neurons and in all dorsal root ganglion cells. This persists until postnatal day 7 and then declines progressively to near adult levels (with low levels of mRNA in spinal cord motor neurons and 2000–3000 DRG cells expressing high levels) at postnatal day 21. A re-expression of GAP-43 mRNA in adult rats is apparent, both in sciatic motor neurons and the majority of L4 and L5 dorsal root ganglion cells, 1 day after sciatic nerve section. High levels of the GAP-43 mRNA in the axotomized spinal motor neurons persist for at least 2 weeks but decline 5 weeks after sciatic nerve section, with the mRNA virtually undetectable after 10 weeks. The initial changes after sciatic nerve crush are similar, but by 5 weeks GAP-43 mRNA in the sciatic motor neurons has declined to control levels. In DRG cells, after both sciatic nerve section or crush, GAP-43 mRNA re-expression persists much longer than in motor neurons. There was no re-expression of GAP-43 mRNA in the dorsal horn of the spinal cord after peripheral nerve lesions. Our study demonstrates a similar developmental regulation in spinal cord and DRG neurons of GAP-43 mRNA. We show moreover that failure of re-innervation does not result in a maintenance of GAP-43 mRNA in axotomized motor neurons.     

Treatment of chronically injured spinal cord with neurotrophic factors stimulates betaII-tubulin and GAP-43 expression in rubrospinal tract neurons

Exogenous neurotrophic factors provided at a spinal cord injury site promote regeneration of chronically injured rubrospinal tract (RST) neurons into a peripheral nerve graft. The present study tested whether the response to neurotrophins is associated with changes in the expression of two regeneration-associated genes, betaII-tubulin and growth-associated protein (GAP)-43. Adult female rats were subjected to a right full hemisection lesion via aspiration of the C3 spinal cord. A second aspiration lesion was made 4 weeks later and gel foam saturated in brain-derived neurotrophic factor (BDNF), glial cell-line derived neurotrophic factor (GDNF), or phosphate-buffered saline (PBS) was applied to the lesion site for 60 min. Using in situ hybridization, RST neurons were examined for changes in mRNA levels of betaII-tubulin and GAP-43 at 1, 3, and 7 days after treatment. Based on analysis of gene expression in single cells, there was no effect of BDNF treatment on either betaII-tubulin or GAP-43 mRNA expression at any time point. betaII-Tubulin mRNA levels were enhanced significantly at 1 and 3 days in animals treated with GDNF relative to levels in animals treated with PBS. Treatment with GDNF did not affect GAP-43 mRNA levels at 1 and 3 days, but at 7 days there was a significant increase in mRNA expression. Interestingly, 7 days after GDNF treatment, the mean cell size of chronically injured RST neurons was increased significantly. Although GDNF and BDNF both promote axonal regeneration by chronically injured neurons, only GDNF treatment is associated with upregulation of betaII-tubulin or GAP-43 mRNA. It is not clear from the present study how exogenous BDNF stimulates regrowth of injured axons.     

Basic fibroblast growth factor attenuates the degeneration of injured spinal cord motor endplates**

The distal end of the spinal cord and neuromuscular junction may develop secondary degeneration and damage following spinal cord injury because of the loss of neural connections. In this study, a rat model of spinal cord injury, established using a modified Allen’s method, was injected with basic fibroblast growth factor solution via subarachnoid catheter. After injection, rats with spinal cord injury displayed higher scores on the Basso, Beattie and Bresnahan locomotor scale. Motor function was also well recovered and hematoxylin-eosin staining showed that spinal glial scar hyperplasia was not apparent. Additionally, anterior tibial muscle fibers slowly, but progressively, atrophied. Immunohistochemical staining showed that the absorbance values of calcitonin gene related peptide and acetylcholinesterase in anterior tibial muscle and spinal cord were similar, and injection of basic fibroblast growth factor increased this absorbance. Results showed that after spinal cord injury, the distal motor neurons and motor endplate degenerated. Changes in calcitonin gene related peptide and acetylcholinesterase in the spinal cord anterior horn motor neurons and motor endplate then occurred that were consistent with this regeneration. Our findings indicate that basic fibroblast growth factor can protect the endplate through attenuating the decreased expression of calcitonin gene related peptide and acetylcholinesterase in anterior horn motor neurons of the injured spinal cord.     

Nischarin-siRNA delivered by polyethylenimine-alginate nanoparticles accelerates motor function recovery after spinal cord injury

A previous study by our group found that inhibition of nischarin promotes neurite outgrowth and neuronal regeneration in Neuro-2 a cells and primary cortical neurons.In recent years,more and more studies have shown that nanomaterials have good prospects in treatment of spinal cord injury.We proposed that small interfering RNA targeting nischarin(Nis-si RNA) delivered by polyethyleneimine-alginate(PEIALG) nanoparticles promoted motor function recovery in rats with spinal cord injury.Direct microinjection of 5 μL PEI-ALG/Nis-si RNA into the spinal cord lesion area of spinal cord injury rats was performed.From day 7 after surgery,Basso,Beattie and Bresnahan score was significantly higher in rats from the PEI-ALG/Nis-si RNA group compared with the spinal cord injury group and PEI-ALG/Control-si RNA group.On day 21 after injection,hematoxylin-eosin staining showed that the necrotic area was reduced in the PEI-ALG/Nis-si RNA group.Immunohistochemistry and western blot assay results confirmed successful inhibition of nischarin expression and increased protein expression of growth-associated protein-43 in the PEI-ALG/Nis-si RNA group.These findings suggest that a complex of PEI-ALG nanoparticles and Nis-si RNA effectively suppresses nischarin expression,induces expression of growth-associated protein-43,and accelerates motor function recovery after spinal cord injury.     

FGF-2 modulates expression and distribution of GAP-43 in frog retinal ganglion cells after optic nerve injury

Basic fibroblast growth factor (bFGF or FGF-2) has been implicated as a trophic factor that promotes survival and neurite outgrowth of neurons. We found previously that application of FGF-2 to the proximal stump of the injured axon increases retinal ganglion cell (RGC) survival. We determine here the effect of FGF-2 on expression of the axonal growth-associated phosphoprotein (GAP)-43 in retinal ganglion cells and tectum of Rana pipiens during regeneration of the optic nerve. In control retinas, GAP-43 protein was found in the optic fiber layer and in optic nerve; mRNA levels were low. After axotomy, mRNA levels increased sevenfold and GAP-43 protein was significantly increased. GAP-43 was localized in retinal axons and in a subset of RGC cell bodies and dendrites. This upregulation of GAP-43 was sustained through the period in which retinal axons reconnect with their target in the tectum. FGF-2 application to the injured nerve, but not to the eyeball, increased GAP-43 mRNA in the retina but decreased GAP-43 protein levels and decreased the number of immunopositive cell bodies. In the tectum, no treatment affected GAP-43 mRNA but FGF-2 application to the axotomized optic nerve increased GAP-43 protein in regenerating retinal projections. We conclude that FGF-2 upregulates the synthesis and alters the distribution of the axonal growth-promoting protein GAP-43, suggesting that it may enhance axonal regrowth.     

Intranasal nerve growth factor bypasses the blood-brain barrier and affects spinal cord neurons in spinal cord injur y

The purpose of this work was to investigate whether, by intranasal administration, the nerve growth factor bypasses the blood-brain barrier and turns over the spinal cord neurons and if such therapeutic approach could be of value in the treatment of spinal cord injury. Adult Sprague-Dawley rats with intact and injured spinal cord received daily intranasal nerve growth factor administration in both nostrils for 1 day or for 3 consecutive weeks. We found an in-creased content of nerve growth factor and enhanced expression of nerve growth factor receptor in the spinal cord 24 hours after a single intranasal administration of nerve growth factor in healthy rats, while daily treatment for 3 weeks in a model of spinal cord injury improved the deifcits in locomotor behaviour and increased spinal content of both nerve growth factor and nerve growth factor receptors. These outcomes suggest that the intranasal nerve growth factor bypasses blood-brain barrier and affects spinal cord neurons in spinal cord injury. They also suggest exploiting the possible therapeutic role of intranasally delivered nerve growth factor for the neuroprotection of damaged spinal nerve cells.     

7, 8-dihydroxycoumarin improves neurological function in a mouse model of sciatic nerve injury

In the present study, a mouse model of sciatic nerve injury was treated with intraperitoneal injection of 7, 8-dihydroxycoumarin (10, 5, or 2.5 mg/kg per day). Western blot and real-time PCR results showed that growth associated protein 43 expression was significantly increased in the L4-6 seg-ments of the spinal cord. The amplitude and velocity of motor nerve conduction in the sciatic nerve were significantly increased in model mice. In addition, the appearance of the myelin sheath in the injured sciatic nerve was regular, with an even thickness and clear outline, and the surrounding fi-broplasia was not obvious. Our results indicate that 7, 8-dihydroxycoumarin can promote the repair of injured nerve by upregulating growth associated protein 43 expression in the corresponding spinal cord segments of mice with sciatic nerve injury.     

Olfactory ensheathing cell transplantation alters the expression of chondroitin sulfate proteoglycans and promotes axonal regeneration after spinal cord injury

Cell transplantation is a potential treatment for spinal cord injury. Olfactory ensheathing cells (OECs) play an active role in the repair of spinal cord injury as a result of the dual characteristics of astrocytes and Schwann cells. However, the specific mechanisms of repair remain poorly understood. In the present study, a rat model of spinal cord injury was established by transection of T10. OECs were injected into the site, 1 mm from the spinal cord stump. To a certain extent, OEC transplantation restored locomotor function in the hindlimbs of rats with spinal cord injury, but had no effect on the formation or volume of glial scars. In addition, OEC transplantation reduced the immunopositivity of chondroitin sulfate proteoglycans (neural/glial antigen 2 and neurocan) and glial fibrillary acidic protein at the injury site, and increased the immunopositivity of growth-associated protein 43 and neurofilament. These findings suggest that OEC transplantation can regulate the expression of chondroitin sulfate proteoglycans in the spinal cord, inhibit scar formation caused by the excessive proliferation of glial cells, and increase the numbers of regenerated nerve fibers, thus promoting axonal regeneration after spinal cord injury. The study was approved by the Animal Ethics Committee of the Medical College of Xi’an Jiaotong University, China (approval No. 2018-2048) on September 9, 2018.

Chinese Library Classification No. R456; R741; Q636.1     

实验性自身免疫性脑脊髓炎大鼠脑白质和脊髓中淀粉样前体蛋白及生长相关蛋白-43的表达

目的：动态观察EAE大鼠脑白质及脊髓中APP及GAP-43在不同病理过程中的表达,以探讨轴突损伤和再生修复的机制。 设计、时间及地点：随机对照动物实验,于2009-6至2010-06在首都医科大学中医药学院完成。 材料：SPF级6-8周龄雌性Lewis大鼠44只,体质量（150±20）g。由北京维通利华实验动物技术有限公司提供。 方法 将大鼠随机分为正常组和不同剂量髓鞘碱性蛋白（Mylin Basic Protein,MBP）68-86诱导的EAE模型组,共3组。造模方法为以含50、25μg的MBP68-86100µl与结核分枝杆菌（Mycobacterium Tubercusis,H37Ra,MTB）2mg及不完全福氏佐剂（Incomplete Freund’s Adjuvant,IFA）100µl混合乳化制成抗原,给大鼠双后足皮下多点注射MBP68-86抗原免疫,建立大鼠EAE模型。正常组只注射生理盐水。 主要观察指标：造模后每天观察动物的发病情况,记录体重变化,进行神经功能评分。选择免疫诱导第14天（急性期）、第28天（缓解期）取大鼠脑和脊髓,利用光镜和电镜观察其病理变化,同时利用Western blot方法检测脑白质和脊髓中APP及GAP-43的蛋白表达。 结果：两组不同剂量MBP68-86均能诱导EAE模型,发病率为100%,呈慢性单相病程。造模后第10天,大鼠开始发病,体重下降,第14天,模型组体重明显低于正常组（p<0.01）,此时神经功能评分达高峰值。苏木精-伊红染色液（hematoxylin-eosin, HE）染色发现：急性期EAE大鼠脑白质出现弥漫性炎细胞浸润,在小血管周围形成 “袖套样”改变;脊髓中,前角运动神经元胞体缩小,核固缩或裂解,小血管周围有大量淋巴细胞浸润,形成典型的“袖套样”改变。缓解期脑与脊髓的病理变化均有所减轻。透射电镜观察发现：模型组急性期脑白质中轴突脱髓鞘明显,线粒体肿胀变形等。高、低剂量组病理变化类似。 Western blot检测发现：模型组脑白质或脊髓中APP高表达于急性期,于缓解期下降。其中,高剂量组EAE模型大鼠脑白质中APP表达水平在第14天显著高于正常组和低剂量组（p<0.05）;第28天APP表达明显下降,与正常组和低剂量组比较,有显著性差异（p<0.01或p<0.05）,且与第14天比较,也有明显下降（p<0.05）。而在脊髓中的APP表达第14天时也有所升高,但无统计学意义,在第28天时无明显变化。低剂量组EAE模型大鼠脑白质和脊髓中APP的表达水平在两个时间点均无显著性变化。 模型组中GAP-43的表达有这种趋势：急性期升高,缓解期降低。高剂量组EAE模型大鼠脑白质中GAP-43在第14天表达水平与正常组比较略有升高,但无显著性差异;在第28天GAP-43表达下降,显著低于正常组和低剂量组（p<0.01或p<0.05）,且显著低于第14天（p<0.05）。脊髓中GAP-43表达在第14天时略有升高,但无明显差异;第28天表达水平与正常组比较无明显变化,但明显高于低剂量组（p<0.05）。低剂量组GAP-43在脑白质中无显著性变化;在脊髓中第14天时GAP-43表达明显高于正常组（p<0.01）,第28天时明显降低,与正常组和第14天比较,有统计学意义（p<0.05）。相关性分析发现：EAE大鼠脑白质和脊髓中APP与GAP-43的表达有明显的正相关关系（p<0.05或p<0.01）。 结论：EAE大鼠轴突损伤后可通过一定的途径部分修复,急性期APP及GAP-43蛋白表达升高,缓解期APP及GAP-43蛋白表达下降,并且二者还存在一定的正相关关系,推测APP及GAP-43可能参与了损伤神经元的自身修复及再生,可能与促进损伤神经元重新构建网络连接有关。     

Transfection of the glial cell line-derived neurotrophic factor gene promotes neuronal differentiation简

Glial cell line-derived neurotrophic factor recombinant adenovirus vector-transfected bone marrow mesenchymal stem cells were induced to differentiate into neuron-like cells using inductive medium containing retinoic acid and epidermal growth factor. Cell viability, micro- tubule-associated protein 2-positive cell ratio, and the expression levels of glial cell line-derived neurotrophic factor, nerve growth factor and growth-associated protein-43 protein in the su- pernatant were significantly higher in glial cell line-derived neurotrophic factor/bone marrow mesenchymal stem cells compared with empty virus plasmid-transfected bone marrow mes- enchymal stem cells. Furthermore, microtubule-associated protein 2, glial cell line-derived neurotrophic factor, nerve growth factor and growth-associated protein743 mRNA levels in cell pellets were statistically higher in glial cell line-derived neurotrophic factor/bone marrow mesen- chymal stem cells compared with empty virus plasmid-transfected bone marrow mesenchymal stem cells. These results suggest that glial cell line-derived neurotrophic factor/bone marrow mesenchymal stem cells have a higher rate of induction into neuron-like cells, and this enhanced differentiation into neuron-like cells may be associated with up-regulated expression of glial cell line-derived neurotrophic factor, nerve growth factor and growth-associated protein-43.     

Growth-associated protein 43 immunoreactivity in the superficial dorsal horn of the rat spinal cord is localized in atrophic C-fiber,and not in sprouted A-fiber,central terminals after peripheral nerve injury

Peripheral nerve injury induces the up-regulation in dorsal root ganglion cells of growth-associated protein 43 (GAP-43) and its transport to the superficial laminae of the dorsal horn of the spinal cord, where it is located primarily in unmyelinated axons and growth-cone like structures. Peripheral nerve injury also induces the central terminals of axotomized myelinated axons to sprout and form novel synaptic contacts in lamina II of the dorsal horn. To investigate whether the sprouting of A-fiber central terminals into lamina II is the consequence of GAP-43 incorporation into their terminal membranes, we have used an ultrastructural analysis with double labelling to identify the localization of GAP-43 immunoreactivity. Transganglionic transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) was used to identify C-fiber terminals. Transganglionic transport of the B fragment of cholera toxin conjugated to horseradish peroxidase (B-HRP) was used to label A-fiber sciatic nerve central terminals in combination with GAP-43 immunocytochemistry. GAP-43 was found to colocalize only with WGA-HRP- and not with B-HRP-labelled synapses or axons. In addition, many single-labelled GAP-43 synapses were observed. Many of the WGA-HRP-labelled terminals that were characterized by degenerative changes were GAP-43 immunoreactive. Our results indicate that peripheral nerve injury induces novel synapse formation of A fibers in lamina II but that up-regulated levels of GAP-43 are present mainly in other axon projections to the superficial dorsal horn. J. Comp. Neurol. 386:111–118, 1997. © 1997 Wiley-Liss, Inc.     

Acidic and basic fibroblast growth factor levels in spinal cord cultures are not regulated by alterations in heparan sulfate proteoglycan expression

The present study was undertaken to assess both the levels of acidic and basic fibroblast growth factors in spinal cord cultures and to determine how they were presented to responsive cells. Western blots detected a single acidic fibroblast growth factor-like protein (17 kDa) and two (18 kDa, 24 kDa) basic fibroblast growth factor-immunoreactive proteins, the levels of which varied with the antibody used. Levels of all three proteins were unaltered in cultures grown in the presence of a mitotic inhibitor, which greatly reduced the number of astrocytes. Cell blots showed increased survival of spinal cord neurons at M_r that corresponded with the three proteins detected immunologically. Solubilized cultures separated on a P100 column showed mitogenic activity for NIH3T3 cells from 17–18 and 24 kDa fractions. Treatment of the cultures with heparitinase did not decrease the levels of acidic and basic fibroblast growth factors detected by Western blots, suggesting that these proteins were not associated with extracellular membrane heparan sulfate proteoglycans. The major fraction of both proteins appeared to be intracellular with a minor amount complexed with extracellular matrix proteins. An inhibitor of xylose-linked proteoglycan synthesis significantly altered heparan sulfate proteoglycan deposition into extracellular matrix, but did not alter the levels of acidic or basic fibroblast growth factors detected by Western blots, or the levels of choline acetyltransferase, glutamic acid decarboxylase, or aspartate aminotransferase activities. These results indicate that both acidic and basic fibroblast growth factors are stored predominantly intracellularly, with only a minor fraction complexed with extracellular proteins. We suggest that these intracellular proteins may be released following injury in the CNS and mediate a cascade of neuroprotective events.     

Induction and axonal localization of epithelial/epidermal fatty acid-binding protein in retinal ganglion cells are associated with axon development and regeneration.

Epithelial/epidermal fatty acid-binding protein (E-FABP) is induced in peripheral neurons during nerve regeneration and is found at high levels in central neurons during neuronal migration and development. Furthermore, E-FABP expression is required for normal neurite outgrowth in PC12 cells treated with nerve growth factor (NGF). The present study examined whether E-FABP plays a role in retinal ganglion cell (RGC) differentiation and axon growth. Rat retinal tissues from embryonic (E) and postnatal (P) development through adulthood were examined using immunocytochemical labeling with E-FABP and growth-associated protein 43 (GAP-43) antibodies. E-FABP colocalized with GAP-43 at E14 through P10. At E14, E-FABP immunoreactivity was confined to the somas of GAP-43-positive cells in the ganglion cell layer, but it was localized to their axons by E15. The axons in the optic nerve were GAP-43-positive and E-FABP-negative on E15, but the two proteins were colocalized by E18. Retinal cultures at E15 confirmed that E-FABP and GAP-43 colocalize in RGCs. Postnatally, labeling was present between P1 and P10 but decreased at older ages and was minimally present or absent in adult animals. Western immunoblotting revealed that at E18, P1, and P10 E-FABP levels were at least fourfold greater than those in the adult. By P15, protein levels were only twofold greater, with adult levels reached by P31. Furthermore, E-FABP could be reinduced during axon regeneration. Dissociated P15 retinal cells cultured in the presence of brain-derived neurotrophic factor, ciliary neurotrophic factor, and basic fibroblast growth factor exhibited sixfold more GAP-43 and E-FABP double-positive RGCs (cell body and axons) than controls. Moreover, all GAP-43-immunoreactive RGCs were also positive for E-FABP. Taken together, these results indicate the following: 1) E-FABP is expressed in RGCs as they reached the ganglion cell layer and 2) E-FABP plays a functional role in the elaboration of RGC axons in both development and regeneration.     

周围神经联合生长因子移植治疗急性脊髓损伤

背景：目前促进神经再生与修复的策略也主要是通过促进神经内在的再生能力和改善再生的微环境两大途径,已有的研究表明联合应用一些治疗手段能更好地促进神经轴突的再生生长。 目的：探讨周围神经联合生长因子移植治疗大鼠脊髓损伤的可行性及效果。 方法：健康成年雌性SD大鼠60只,随机数字表法分为4组：神经移植组、神经移植联合生长因子组、脊髓横断组、椎板切除组。以T9为中心纵行切开大鼠皮肤,显露硬膜囊,水平切断脊髓并切除3mm,神经移植组、神经移植联合生长因子组取双侧第8~10对肋间神经各2 cm,将自体肋间神经修剪成合适长度后交叉移植入脊髓缺损处(近端白质与远端灰质、远端白质与近端灰质),神经移植组用纤维蛋白凝胶固定植入的肋间神经,神经移植联合生长因子组用含有2.1 mg/L 酸性成纤维细胞生长因子的纤维蛋白凝胶固定植入的肋间神经,缝合硬膜。脊髓横断组断端间旷置,椎板切除组仅行椎板切除术。术后90 d进行体感及运动诱发电位检测,术后70 d进行Basso.Beattie.Bresnahan(BBB)后肢运动功能评分。 结果与结论：椎板切除组均引出了体感及运动诱发电位;脊髓横断组未引出体感及运动诱发电位波形;神经移植组3只引出双侧体感诱发电位,4只引出单侧体感诱发电位,4只引出双侧运动诱发电位,3只引出单侧运动诱发电位,神经移植联合生长因子组5只引出双侧体感诱发电位,2只引出单侧体感诱发电位,神经移植联合生长因子组5只引出双侧运动诱发电位,2只引出单侧运动诱发电位。神经移植组、神经移植联合生长因子组大鼠体感及运动诱发电位潜伏期及波幅明显优于脊髓横断组(P < 0.01),自体肋神经移植联合生长因子组优于神经移植组(P < 0.01)。椎板切除组大鼠麻醉清醒后运动恢复正常, 脊髓横断组在3个月的生存期内后肢持续伸展、旋转,神经移植组和神经移植联合生长因子组大鼠后肢功能术后3周开始明显恢复,并在整个观察期内逐渐恢复。神经移植组和神经移植联合生长因子组BBB后肢运动功能评分较脊髓横断组明显提高(P < 0.01),并且神经移植联合生长因子组较神经移植组高(P < 0.01)。提示单纯周围神经移植能部分恢复脊髓功能,联合生长因子则能更好地恢复脊髓功能。     

Establishment of pure neuronal cultures from fetal rat spinal cord and proliferation of the neuronal precursor cells in the presence of fibroblast growth factor.

A primary culture system of nearly pure neuronal cells from 14-day-old fetal rat spinal cord has been developed by combining a preplating step, the use of a chemically defined serum-free medium, and borated polylysine-coated dishes that prevented the formation of cell aggregates. About 98% of the cells were found to be immunostained with neuron-specific enolase antibodies, confirming their neuronal nature. The cultures are composed essentially of a population of non-motoneurons and contain few motoneurons, characterized by their large size and multipolar aspect, the presence of acetylcholinesterase (AChE), and the intense immunoreaction for growth-associated protein GAP-43. Neuronal precursor cells are also present in these cultures and proliferate during the first 3 days. The addition of bovine brain basic fibroblast growth factor (bFGF) stimulates their proliferation over a period of 2 days, as determined by measurement of [125I]iododeoxyuridine incorporation and by immunocytochemical reaction after bromodeoxyuridine incorporation into nuclei. The proliferating cells were characterized as neurons by immunostaining against neuron-specific enolase. Recombinant human bFGF and bovine brain acidic FGF (aFGF) exerted similar effects. Other growth factors, including epidermal growth factor (EGF), transforming growth factor beta 1 (TGF-beta 1), and thrombin, were without effect on the proliferative activity of these neuronal cells. bFGF has no effect on the survival of motoneurons and on the fiber outgrowth of the whole neuronal population. However, bFGF affects the development of bipolar AChE-positive neurons, probably belonging to the non-motoneuron population. The data indicate that bFGF and aFGF are mitogens for neuroblasts from rat spinal cord in culture and that bFGF influences the development of a subpopulation of spinal neurons that are AChE-positive.     

Elevated gene expression in the red nucleus after spinal cord compression injury.

Since the mechanism of injury in the majority of human traumatic spinal cord injuries involves rapid cord compression due to bone displacement or fracture-dislocation, we have used a compression injury model to examine the response of adult rat rubrospinal neurons to traumatic spinal cord injury. We have applied in situ hybridization techniques to examine levels of mRNA for cytoskeletal and growth-associated proteins. We report a population of magnocellular red nucleus neurons with elevated levels of T alpha 1 tubulin and GAP-43 up to four weeks post-lesion. In control animals, both probes had very low hybridization signals indistinguishable from background. These and other findings suggest that kinetic compression injuries of the adult spinal cord can result in regeneration-associated gene expression in intrinsic CNS neurons.