可注射神经生长因子缓释制剂的体外释药性能

目的:观察可注射神经生长因子(NGF)缓释制剂的一般性质和体外释药特征。方法:采用药物微球技术制备的NGF微球,与生物纤维蛋白胶混合形成NGF复合缓释制剂,并通过体外释放率和PC12细胞活性考察其体外释药性质。结果:体外实验证明,NGF复合缓释制剂可持续释放NGF达7周以上,累积释放率为63.85%,释出的NGF可促进PC12细胞分化,具有较强的生物学活性,出现神经突触样生长。结论:制备可注射NGF缓释制剂,可长期释放NGF,并具有生物活性,可作为补充外源性NGF的良好制剂。     

Nanofibrous gelatine scaffolds integrated with nerve growth factor‐loaded alginate microspheres for brain tissue engineering

Neural regeneration research is designed in part to develop strategies for therapy after nerve damage due to injury or disease. In this study, a new gelatine‐based biomimetic scaffold was fabricated for brain tissue engineering applications. A technique combining thermally induced phase separation and porogen leaching was used to create interconnected macropores and nanofibrous structure. To promote tissue regeneration processes, the scaffolds were integrated with nerve growth factor (NGF)‐loaded alginate microspheres. The results showed that nanofibrous matrix could only be obtained when gelatine concentration was at least 7.5% (w/v). The scaffold with a modulus value (1.2 kPa) similar to that of brain tissue (0.5–1 kPa) was obtained by optimizing the heat treatment time, macropore size and gelatine concentration. The encapsulation efficiencies of NGF into 0.1% and 1% alginate microspheres were 85% and 100%, respectively. The release rate of NGF from the microspheres was controlled by the alginate concentration and the poly(L‐lysine) coating. The immobilization of the microspheres in the scaffold reduced burst release and significantly extended the release period. The nanofibrous architecture and controlled release of NGF from the microspheres induced neurite extension of PC12 cells, demonstrating that the released NGF was in an active form. The results suggest that the scaffolds prepared in this study may have potential applications in brain tissue engineering due to topologic and mechanical properties similar to brain tissue and pore structure suitable for cell growth and differentiation. Copyright © 2016 John Wiley & Sons, Ltd.     

改良复乳法制备神经生长因子微球及其体外释药性能

背景:已往研究表明,神经生长因子微球对脊髓损伤的修复有促进作用.然而,传统复乳法制备微球过程中诸多因素会严重影响生物大分子药物的生物活性,如何改善制备工艺提高微球的缓释性能至关重要.目的:课题提出改良复乳法制备神经生长因子微球的方法,并考察和验证其一般性质和体外释药特征.设计、时间及地点:随机对照细胞学实验,于2008-05/2009-05在温州医学院药学院及温州医学院附属第二医院骨科分子生物学实验室完成.材料:重组人神经生长因子(美国R&D公司),乳酸/羟基乙酸共聚物(聚乳酸/聚羟基乙酸75/25,Mw=20 000,黏度=0.025 L/g)(山东省医疗器械研究所);聚乙烯醇(日本可乐丽公司);聚乙二醇400(德国AppliChem公司).方法:以乳酸/羟基乙酸共聚物为载体材料,对传统复乳溶剂挥发法进行改进,采用全循环一体机装置制备神经生长因子缓释微球,对缓释微球的物理表观性质进行检测,然后通过EUSA+Kit法和PC12细胞共培养法来检测微球中神经生长因子的活性.主要观察指标:以微球形态、粒径、包封率等为评价指标,并通过体外释放率和PC12细胞活性考察其体外释药性质.结果:改良法和传统法制备的微球粒径分别为(22.61±3.94)μm和(21.32±4.82)μm,包封率分别为(92.08±4.39)%和(89.17±3.74)%.改良组的神经生长因子微球可以持续分泌有生物活性的神经生长因子长达7周,累积释放率为85.7%,而传统组的微球只能释放4周,累积释放率为60 8%,且第4周时释放的神经生长因子活性明显低于改良组,差异有显著性意义(P<0.01).结论:改良法制备的神经生长因子微球粒径适宜、包封率高,较传统复乳溶剂挥法制备的微球有更好的缓释性能.     

Strategies for neurotrophin‐3 and chondroitinase ABC release from freeze‐cast chitosan–alginate nerve‐guidance scaffolds

Freeze casting, or controlled unidirectional solidification, can be used to fabricate chitosan–alginate (C–A) scaffolds with highly aligned porosity that are suitable for use as nerve‐guidance channels. To augment the guidance of growth across a spinal cord injury lesion, these scaffolds are now evaluated in vitro to assess their ability to release neurotrophin‐3 (NT‐3) and chondroitinase ABC (chABC) in a controlled manner. Protein‐loaded microcapsules were incorporated into C–A scaffolds prior to freeze casting without affecting the original scaffold architecture. In vitro protein release was not significantly different when comparing protein loaded directly into the scaffolds with release from scaffolds containing incorporated microcapsules. NT‐3 was released from the C–A scaffolds for 8 weeks in vitro, while chABC was released for up to 7 weeks. Low total percentages of protein released from the scaffolds over this time period were attributed to limitation of diffusion by the interpenetrating polymer network matrix of the scaffold walls. NT‐3 and chABC released from the scaffolds retained bioactivity, as determined by a neurite outgrowth assay, and the promotion of neurite growth across an inhibitory barrier of chondroitin sulphate proteoglycans. This demonstrates the potential of these multifunctional scaffolds for enhancing axonal regeneration through growth‐inhibiting glial scars via the sustained release of chABC and NT‐3. Copyright © 2014 John Wiley & Sons, Ltd.     

Let-7 microRNAs Regenerate Peripheral Nerve Regeneration by Targeting Nerve Growth Factor

Peripheral nerve injury is a common clinical problem. Nerve growth factor (NGF) promotes peripheral nerve regeneration, but its clinical applications are limited by several constraints. In this study, we found that the time-dependent expression profiles of eight let-7 family members in the injured nerve after sciatic nerve injury were roughly similar to each other. Let-7 microRNAs (miRNAs) significantly reduced cell proliferation and migration of primary Schwann cells (SCs) by directly targeting NGF and suppressing its protein translation. Following sciatic nerve injury, the temporal change in let-7 miRNA expression was negatively correlated with that in NGF expression. Inhibition of let-7 miRNAs increased NGF secretion by primary cultured SCs and enhanced axonal outgrowth from a coculture of primary SCs and dorsal root gangalion neurons. In vivo tests indicated that let-7 inhibition promoted SCs migration and axon outgrowth within a regenerative microenvironment. In addition, the inhibitory effect of let-7 miRNAs on SCs apoptosis might serve as an early stress response to nerve injury, but this effect seemed to be not mediated through a NGF-dependent pathway. Collectively, our results provide a new insight into let-7 miRNA regulation of peripheral nerve regeneration and suggest a potential therapy for repair of peripheral nerve injury.     

NGF／PLGA复合神经导管修复大鼠周围神经缺损的实验研究

目的：应用神经生长因子（NGV）、聚乳酸和聚羟基乙酸的共聚物（PLGA）和牛血清白蛋白（BSA）制成NGF／PLGA复合神经导管。检测其综合性能和了解其修复大鼠周围神经缺损的可能性。方法：体外模拟体内环境，检测它的降解时间及用ELISA的方法来检测NGF的释放情况；手术造成大鼠坐骨神经约10mm的缺损，分别采用自体神经移植（A组）、NGF／PLGA复合神经导管桥接（B组）和单纯PLGA导管（C组）桥接，术后4、8、12周进行大体观察、神经电生理测定、HE染色、变色酸2R一亮绿髓鞘染色、电镜观察和图像分析对比。结果：在体外NGF／PLGA复合神经导管能在体外释放NGF约18天，约在14周左右导管降解完毕。NGF／PLGA神经导管组在促进坐骨神经再生、再生神经纤维排列规律化、提高再生神经髓鞘化、加速再生神经功能重建等方面均优于单纯PLGA导管组。比自体神经移植组略差。结论：NGF，PLGA复合神经导管具有良好的组织相容性，对大鼠坐骨神经缺损具有良好的桥梁作用和促神经生长的作用，效果接近自体神经移植。     

Regenerative effects of human embryonic stem cell‐derived neural crest cells for treatment of peripheral nerve injury

Surgical intervention is the current gold standard treatment following peripheral nerve injury. However, this approach has limitations, and full recovery of both motor and sensory modalities often remains incomplete. The development of artificial nerve grafts that either complement or replace current surgical procedures is therefore of paramount importance. An essential component of artificial grafts is biodegradable conduits and transplanted cells that provide trophic support during the regenerative process. Neural crest cells are promising support cell candidates because they are the parent population to many peripheral nervous system lineages. In this study, neural crest cells were differentiated from human embryonic stem cells. The differentiated cells exhibited typical stellate morphology and protein expression signatures that were comparable with native neural crest. Conditioned media harvested from the differentiated cells contained a range of biologically active trophic factors and was able to stimulate in vitro neurite outgrowth. Differentiated neural crest cells were seeded into a biodegradable nerve conduit, and their regeneration potential was assessed in a rat sciatic nerve injury model. A robust regeneration front was observed across the entire width of the conduit seeded with the differentiated neural crest cells. Moreover, the up‐regulation of several regeneration‐related genes was observed within the dorsal root ganglion and spinal cord segments harvested from transplanted animals. Our results demonstrate that the differentiated neural crest cells are biologically active and provide trophic support to stimulate peripheral nerve regeneration. Differentiated neural crest cells are therefore promising supporting cell candidates to aid in peripheral nerve repair.     

The advances in nerve tissue engineering: From fabrication of nerve conduit to in vivo nerve regeneration assays

Peripheral nerve damage is a common clinical complication of traumatic injury occurring after accident, tumorous outgrowth, or surgical side effects. Although the new methods and biomaterials have been improved recently, regeneration of peripheral nerve gaps is still a challenge. These injuries affect the quality of life of the patients negatively. In the recent years, many efforts have been made to develop innovative nerve tissue engineering approaches aiming to improve peripheral nerve treatment following nerve injuries. Herein, we will not only outline what we know about the peripheral nerve regeneration but also offer our insight regarding the types of nerve conduits, their fabrication process, and factors associated with conduits as well as types of animal and nerve models for evaluating conduit function. Finally, nerve regeneration in a rat sciatic nerve injury model by nerve conduits has been considered, and the main aspects that may affect the preclinical outcome have been discussed.     

The Akt-nitric oxide-cGMP pathway contributes to nerve growth factor-mediated neurite outgrowth in apolipoprotein E knockout mice

Apolipoprotein E (apo)-deficient [apoE(-/-)] mice have peripheral sensory nerve defects and a reduced and delayed response to noxious thermal stimuli. However, to date, no report has focused on the influence of apoE deficiency on calcitonin gene-related peptide (CGRP)-containing nerve fiber extensions. We have shown that the density of CGRP-containing nerve fibers decreases in mesenteric arteries of apoE(-/-) mice compared with wild-type mice. Here, we investigated whether apoE deficiency is involved in nerve growth factor (NGF)-induced CGRP-containing nerve regeneration using apoE(-/-) mice. NGF-mediated CGRP-like immunoreactivity (LI)-neurite outgrowth in apoE(-/-) cultured dorsal root ganglia (DRG) cells was significantly lower than that in wild-type cultures. However, the level of NGF receptor mRNA in apoE(-/-) DRG cells was similar to that in wild-type mice. To clarify the mechanism of the impaired ability of NGF-mediated neurite outgrowth, we focused on the Akt-nitric oxide (NO)-cGMP pathway. Expression of phosphorylated Akt was significantly reduced in apoE(-/-) DRG. The NO donor, sodium nitroprusside or S-nitroso-N-acetylpenicillamine, did not affect NGF-mediated neurite outgrowth in apoE(-/-) cultured DRG cells. However, 8-bromoguanosine 3',5'-cyclic monophosphate sodium salt n-hydrate, a cGMP analog, induced NGF-mediated nerve facilitation similar to wild-type NGF-mediated neurite outgrowth levels. Furthermore, in apoE(-/-) DRG, soluble guanylate cyclase expression was significantly lower than that in wild-type DRG. These results suggest that in apoE(-/-) mice the Akt-NO-cGMP pathway is impaired, which may be caused by NGF-mediated CGRP-LI-neurite outgrowth defects.     

化学去细胞同种异体神经复合神经生长因子移植后运动功能神经生理学观察

目的:观察化学去细胞同种异体神经复合神经生长因子(NGF)修复大鼠坐骨神经缺损的神经生理恢复情况。方法:采用药物微球技术制备的NGF微球,与生物纤维蛋白胶混合后,形成NGF复合缓释制剂,作为补充外源性NGF载体。选取30只Wister大鼠制备坐骨神经10 mrn缺损进行神经修复,随机分为A、B、C3组,A组予自体神经反转吻合,B组予化学去细胞异体神经桥接,C组在化学去细胞神经移植段周围注射1 mL的NGF复合缓释制剂。术后16周观察大鼠在运动功能神经生理学恢复的情况。结果:方波刺激移植段近侧神经,均在小腿三头肌上记录到运动诱发电位曲线。A、B、C组的神经移植段运动传导速度分别为(52.6±3.9)、(35.4±3.2)、(47.2±3.8)m/s,A组与C组比较无统计学差异,B组与C组比较差异有统计学意义(P<0.05)。结论:化学去细胞神经同种异体复合NGF缓释制剂移植修复大鼠坐骨神经长段缺损,术后4个月运动传导功能恢复与自体神经移植相似。     

生物材料构建神经导管修复周围神经损伤的临床应用

背景:显微外科技术及周围神经损伤修复技术的发展与神经导管材料密切相关。神经导管的构建特别是生物材料构建神经导管材料还有待进一步开发研究。目的:探讨生物材料构建的神经导管在周围神经损伤修复中的应用及数据分析。方法:SCI数据库中2001/2010检索有关神经导管在周围神经损伤修复中的应用的文献,检索词为"神经导管(nerve conduit);生物材料(biomaterials);周围神经损伤(peripheral nerve injury);神经再生(nerve regeneration);壳聚糖神经导管(chitosan/chitin nerve conduit);高分子神经导管(polymer/macromolecule nerve conduit);胶原神经导管(collagen nerve conduit)",共检索文献183篇。结果与结论:神经导管修复法是在神经断端之间留有一段间隙,利用神经导管在神经的远端和近端之间桥接,并创造相对密闭的环境,以充分发挥远端神经的趋化作用,同时阻隔外部的影响,减少瘢痕的产生。目前,已被用于制备神经导管材料分为非神经组织、非生物降解材料、可生物降解材料。随着分子生物学及其他相关技术的发展,探索寻找理想的材料构建神经导管来治疗周围神经损伤研究始终在进行中。     

Biodegradable polymeric microspheres with "open/closed" pores for sustained release of human growth hormone.

A new approach for attaining sustained release of protein is introduced, involving a pore-closing process of preformed porous PLGA microspheres. Highly porous biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were fabricated by a single water-in-oil emulsion solvent evaporation technique using Pluronic F127 as an extractable porogen. Recombinant human growth hormone (rhGH) was incorporated into porous microspheres by a simple solution dipping method. For their controlled release, porous microspheres containing hGH were treated with water-miscible solvents in aqueous phase for production of pore-closed microspheres. These microspheres showed sustained release patterns over an extended period; however, the drug loading efficiency was extremely low. To overcome the drug loading problem, the pore-closing process was performed in an ethanol vapor phase using a fluidized bed reactor. The resultant pore-closed microspheres exhibited high protein loading amount as well as sustained rhGH release profiles. Also, the released rhGH exhibited structural integrity after the treatment.     

Incorporation of protein-eluting microspheres into biodegradable nerve guidance channels for controlled release.

Nerve guidance channels (NGCs) promote axonal regeneration after transection injury of the peripheral nerve or spinal cord, yet this regeneration is limited. To enhance regeneration further, we hypothesize that localized delivery of therapeutic molecules combined with the NGC is required. In an attempt to achieve such an NGC, we designed and synthesized a novel NGC in which protein-encapsulated microspheres were stably incorporated into the tube wall. Specifically, poly(lactide-co-glycolide) (PLGA 50/50) microspheres were physically entrapped in the annulus between two concentric tubes, consisting of a chitosan inner tube and a chitin outer tube. Taking advantage of the extensive shrinking that the outer chitin tube undergoes with drying, >15 mg of microspheres were loaded within the tube walls. Using BSA-encapsulated microspheres as the model drug delivery system, BSA was released from microsphere loaded tubes (MLTs) for 84 days, and from freely suspended PLGA microspheres for 70 days. An initial burst release was observed for both MLTs and free microspheres, followed by a degradation-controlled release profile that resulted in a higher release rate from MLTs initially, which was then attenuated likely due to the buffering effect of chitin and chitosan tubes. Epidermal growth factor (EGF), co-encapsulated with BSA in PLGA 50/50 microspheres in MLTs, was released for 56 days with a similar profile to that of BSA. Released EGF was found to be bioactive for at least 14 days as assessed by a neurosphere forming bioassay.     

Differentiated adipose‐derived stem cells act synergistically with RGD‐modified surfaces to improve neurite outgrowth in a co‐culture model

Peripheral nerve damage is a problem encountered after trauma and during surgery and the development of synthetic polymer conduits may offer a promising alternative to autografts. In order to improve the performance of the polymer to be used for nerve conduits, poly‐ε‐caprolactone (PCL) films were chemically functionalized with RGD moieties, using a chemical reaction previously developed. In vitro cultures of dissociated dorsal root ganglion (DRG) neurons provide a valid model to study different factors affecting axonal growth. In this work, DRG neurons were cultured on RGD‐functionalized PCL films. Adult adipose‐derived stem cells differentiated to Schwann cells (dASCs) were initially cultured on the functionalized PCL films, resulting in improved attachment and proliferation. dASCs were also co‐cultured with DRG neurons on treated and untreated PCL to assess stimulation by dASCs on neurite outgrowth. Neuron response was generally poor on untreated PCL films, but long neurites were observed in the presence of dASCs or RGD moieties. A combination of the two factors enhanced even further neurite outgrowth, acting synergistically. Finally, in order to better understand the extracellular matrix (ECM)–cell interaction, a β1 integrin blocking experiment was carried out. Neurite outgrowth was not affected by the specific antibody blocking, showing that β1 integrin function can be compensated by other molecules present on the cell membrane. Copyright © 2013 John Wiley & Sons, Ltd.     

胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合应用损伤脊髓再生的形态学变化

背景:促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。目的:探讨胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。方法:建立SD大鼠T10脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。结果与结论:胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。     

Human dermal microvascular endothelial cells produce nerve growth factor: implications for wound repair

Following cutaneous injury, sensory nerves regenerate into the dermis and epidermis. Tissues that are innervated by sensory nerves synthesize neurotrophins such as nerve growth factor (NGF). The close anatomic proximity of nerves and capillaries throughout the skin suggests that mutual regulation may exist between nerve fibers and microvascular endothelial cells (MECs) during wound repair. Release of the neuropeptide substance P by sensory nerves induces endothelial cell rounding, capillary leak, and cytokine upregulation. We propose that dermal endothelial cells produce neurotrophins required for nerve fiber maintenance and regeneration. In this study, we demonstrate that substance P stimulates NGF messenger RNA expression by cultured human dermal MECs. Likewise, enzyme-linked immunosorbant assay demonstrated that conditioned medium from cultured dermal MECs contains NGF. NGF bioactivity in the supemates was verified by conditioned medium-induced clonal rat pheochromocytoma (PC-12) cell differentiation. This activity was inhibited by anti-NGF antibodies. Therefore, we have demonstrated that substance P, an inflammatory neuropeptide released by sensory nerve fibers, induces endothelial cells to produce NGF. Our data suggest that MECs may be unrecognized contributors to nerve regeneration after cutaneous injury.     

胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合应用损伤脊髓再生的形态学变化

背景：促进轴突再生的原则是改善抑制再生的环境和提高轴突生长能力,措施主要有轴突生长抑制因子阻滞剂和神经营养因子应用。用可降解微球加载药物是一种在局部提供持续药物释放的方法。目的：探讨胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合应用促进大鼠损伤脊髓再生病理形态学修复的作用。方法：建立SD大鼠T10脊髓完全横断伤模型,分别在损伤局部给予生理盐水、胶质细胞源性神经营养因子、胶质细胞源性神经营养因子缓释微球、NogoA缓释微球、ChABC缓释微球及3种微球联合治疗,并设立未造模的正常组及假手术组。损伤后10周,每组行四甲基若丹明葡聚糖胺顺行示踪,及神经丝蛋白200、生长相关蛋白43、胶质细胞源性神经营养因子免疫组化检查,并采用免疫组化图像分析系统进行定量分析。结果与结论：胶质细胞源性神经营养因子、NogoA、ChABC缓释微球联合能提高脊髓损伤局部神经丝蛋白200、生长相关蛋白43、胶质纤维酸性蛋白的表达水平,显示局部脊髓再生修复加强,其效果优于单用胶质细胞源性神经营养因子缓释微球。提示,胶质细胞源性神经营养因子缓释微球及NogoA,ChABC缓释微球联合促大鼠损伤脊髓再生修复其效果优于单用胶质细胞源性神经营养因子缓释微球。     

Delivery of chondroitinase ABC and glial cell line‐derived neurotrophic factor from silk fibroin conduits enhances peripheral nerve regeneration

Nerve conduits are a proven strategy for guiding axon regrowth following injury. This study compares degradable silk–trehalose films containing chondroitinase ABC (ChABC) and/or glial cell line‐derived neurotrophic factor (GDNF) loaded within a silk fibroin‐based nerve conduit in a rat sciatic nerve defect model. Four groups of silk conduits were prepared, with the following silk–trehalose films inserted into the conduit: (a) empty; (b) 1 µg GDNF; (3) 2 U ChABC; and (4) 1 µg GDNF/2 U ChABC. Drug release studies demonstrated 20% recovery of GDNF and ChABC at 6 weeks and 24 h, respectively. Six conduits of each type were implanted into 15 mm sciatic nerve defects in Lewis rats; conduits were explanted for histological analysis at 6 weeks. Tissues stained with Schwann cell S‐100 antibody demonstrated an increased density of cells in both GDNF‐ and ChABC‐treated groups compared to empty control conduits (p < 0.05). Conduits loaded with GDNF and ChABC also demonstrated higher levels of neuron‐specific PGP 9.5 protein when compared to controls (p < 0.05). In this study we demonstrated a method to enhance Schwann cell migration and proliferation and also foster axonal regeneration when repairing peripheral nerve gap defects. Silk fibroin‐based nerve conduits possess favourable mechanical and degradative properties and are further enhanced when loaded with ChABC and GDNF. Copyright © 2014 John Wiley & Sons, Ltd.     

神经生长因子对脑缺血再灌注后生长相关蛋白和突 …

目的 研究外源性神经生长因子（ＮＧＦ）对大鼠脑缺血再灌注后生长相关蛋白－４３）ＧＡＰ－４３）和突触素ｐ３８表达的影响。方法 成年健康雌性Ｗｉｓｔａｒ大鼠５４只，随机分为ＮＧＦ治疗组、对照组和假手术组。采用线栓法建立大脑中动脉缺血再灌注动物模型，应用免疫组织化学方法观察ＮＧＦ对脑缺血再灌注后ＧＡＰ－４３和ｐ３８表达的影响。结果 脑主射外缘性ＮＧＦ后，ＧＡＰ－４３和ｐ３８表达较对照组有所增高，但差异无     

许旺细胞及小肠黏膜下层复合生长因子缓释微球修复周围神经缺损

背景：前期实验已初步证实许旺细胞复合小肠黏膜下层及碱性成纤维细胞生长因子构建的人工神经具有体外神经活性、趋化性。目的：观察许旺细胞及小肠黏膜下层复合碱性成纤维细胞生长因子缓释微球修复周围神经缺损后神经传导的再通情况。方法：制作SD大鼠坐骨神经缺损模型,随机分组：实验组以许旺细胞及小肠黏膜下层复合碱性成纤维细胞生长因子缓释微球修复,阳性对照组以许旺细胞及小肠黏膜下层复合游离碱性成纤维细胞生长因子修复,阴性对照组以许旺细胞及小肠黏膜下层修复,空白对照组以自体神经修复。结果与结论：术后16周实验组再生神经纤维数目,DiI示踪标记的阳性神经元数量、S-100及神经细丝蛋白的阳性表达率、髓鞘及再生轴突的超微结构恢复、神经传导速度及复合动作电位的改善均优于阳性对照组与阴性对照组（P〈0.05）。表明许旺细胞复合小肠黏膜下层及碱性成纤维细胞生长因子缓释微球构建的人工神经可重建坐骨神经缺损后的神经传导通路。