神经生长因子的研究

神经生长因子的研究湖南医科大学李叔庚神经生长因子（ｎｅｒｖｅｇｒｏｗｔｈｆａｃｔｏｒＮＧＦ）是神经系统最重要的生物活性分子之一,也是最早发现和最典型的神经营养因子,它影响外周和中枢神经系统某些神经元的存活和分化［１］。１９４８年Ｂｕｅｋｅｒ首次发现将...     

冻干神经生长因子活性稳定性试验研究

用不同的物质作保护剂冻干纯化鼠神经生长因子,经检定以人血白蛋白作为赋形剂和保护剂冻干神经生长因子制品外观洁白细腻,结构强度良好,生物活性符合要求,残存水分低于３％。采用留样观察法检测其稳定性,将制品放置４℃～８℃,在０、０．５、１、２、３、６、９、１２、１８、２４、２５个月分别测定其各自的活性。结果表明神经生长因子冻干制品在４℃～８℃保存,２５个月仍然保持原有生物活性     

周围神经异体移植免疫机制的研究进展

周围神经异体移植由于移植物免疫原性的存在,移植后受体产生免疫排斥反应,造成移植失败。本文综述了移植物的免疫成分所在、SC及细胞因子在排斥反应中的作用、T淋巴细胞的激活途径及激活信号的转导过程,并讨论了减轻免疫排斥反应的治疗进展。     

HSV-1感染对神经胶质瘤细胞神经生长因子及其受体表达的影响

神经生长因子(NGF)主要由神经胶质细胞产生,通过特异的靶细胞表面的神经生长因子受体介导产生生物学效应,与神经细胞的生长发育、分化和凋亡等密切相关。单纯疱疹病毒1型(HSV-1)作为一种嗜神经病毒,易造成神经细胞、神经胶质细胞凋亡或死亡。本实验以U251人神经胶质瘤细胞为研究对象,观察HSV-1感染致U251细胞凋亡的过程中NGF及其受体的变化情况。结果发现U251细胞是HSV-1的容许细胞;HSV-1感染致U251细胞凋亡过程中,NGF及其低亲和力受体p75NTR出现表达强度随时间先增强后减弱的趋势,而高亲和受体Tr-kA持续低表达。推测HSV-1感染致神经细胞凋亡中可能调控了神经营养因子的表达。     

神经生长因子的信号转导

神经生长因子的信号转导李智任一萍（华东师范大学生物系,上海２０００６２）关键词神经生长因子神经营养蛋白神经营养因子信号转导图１ＮＧＦ的信号转导机制Ａ．ＮＧＦ的信号转导概况Ｂ．Ｒａｓ的激活？未知转录调节因子．——转导途径．促进．抑制神经生长因子（ｎ...     

兔异体脂肪干细胞移植的实验研究

目的:建立一种可注射异体脂肪移植模型,观察兔异体脂肪干细胞(adipose-derived stem cells,ADSCs)复合自体脂肪颗粒(adipose granule,AG)和富血小板纤维蛋白(platelet-rich fibrin,PRF)移植后的形态学和免疫学的变化,为临床异体脂肪干细胞移植提供一种实验依据.方法:取30只健康新西兰家兔,随机分成5组:A组,(N=6),移植物为自体AG;B组,(N=6),自体AG+自体PRF;C组(N=6),自体AG+自体ADSCs:D组(N=6),自体AGr自体PRF+自体ADSCs,E组(N＝6),实验组,自体AG+自体PRF+异体ADSCs.在术后1、3、6个月,大体外观、HE染色分析其形态学改变;免疫组化、外周血淋巴细胞亚群CD4/CD8比值、血浆IL2和IL4分析其免疫学改变.结果:术后l、3、6个月在大体外观、免疫组化等D、E两组与A、B、C三组比较均有显著性差异(P＜0.05).E组在淋巴亚群CD4/CD8、血浆IL-2、IL-4等与D组比较均无显著性差异(P＞0.05).结论:异体ADSCs复合自体PRF、AG能够显著提高移植脂肪组织的成活率,并且无明显免疫排斥反应,可为临床异体脂肪干细胞移植提供实验依据.     

神经营养素3和脑源性神经生长因子在大鼠脊髓中的定位表达

神经营养素3（NT－3）和脑源性神经生长因子（BDNF）是神经生长因子（NGF）的同源物,体外实验表明NT－3和BDNF能促进感觉神经元和交感神经元的存活,但是NT－3和BDNF在脊髓中的生物学作用和定位分布还不十分清楚。本用免疫组化ABC法观察了NT－3和BDNF的免疫阳性反应物在大鼠脊髓中的分布。结果表明：呈NT－3样免疫阳性反应的胶质细胞分布于脊髓的后索、侧索和前索中;免疫反应阳性的神经元主要见于脊髓前角,少数见于脊髓后角。BDNF位于大鼠的脊髓前角动物神经元;在脊髓Ⅱ板层中还可见较多的BDNF免疫反应阳性的神经终末。提示NT－3和BDNF在维持脊髓神经元和胶质细胞的生理功能中可能起重要作用。     

鼠神经生长因子对电烧伤患者神经修复的作用及其机制研究

目的:探讨鼠神经生长因子对电烧伤患者神经修复的作用及其机制。方法:选取2013年2月至2014年11月期间我院确诊治疗的四肢电烧伤患者128例,依据随机分配原则分为对照组和神经组,对照组患者给予常规皮瓣修复术治疗,神经组患者在此基础上给予鼠神经生长因子治疗,且依据给药方式分为全身亚组和局部亚组。统计分析所有患者创面愈合时间、感染和出血发生情况,采用BMRC感觉、运动功能评级法评估患者感觉、运动功能恢复情况,应用Spearman分析法分析二者之间的关系。结果:神经组患者创面愈合时间、感染和出血发生率明显低于对照组,差异有统计学意义(P0.05);局部亚组患者感觉功能优良率为90.63%,全身亚组为84.38%,对照组为71.88%,局部亚组全身亚组对照组,差异有统计学意义(P0.05);局部亚组患者运动功能优良率为93.75%,全身亚组为84.38%,对照组为76.56%,局部亚组全身亚组对照组,差异有统计学意义(P0.05);Spearman分析法结果显示,感觉功能与运动功能呈正相关(r=0.812,P0.05)。结论:鼠神经生长因子可有效提高电烧伤患者神经修复的作用,有利于改善患者术后创面愈合、感染、出血情况,促进患者感觉、运动功能恢复,且通过局部给药方式具有更为良好的神经修复作用,值得临床作进一步推广。     

毛囊来源的神经嵴干细胞修复大鼠坐骨神经缺损

毛囊来源的神经嵴干细胞(Epidermal Neural Crest Stem Cell,EPI-NCSC)由于取材方便,具有多种分化潜能,是一种具有良好应用前景的组织工程种子细胞。目前,在神经损伤修复领域中,EPI-NCSC主要被应用于脊髓损伤的修复。为了探讨EPI-NCSC对周围神经缺损的修复作用,对原代培养的GFP-SD大鼠来源的EPI-NCSC的体外性质进行了考察,并以其为种子细胞,将其等量与细胞外基质(Extracellular matrix,ECM)混合后,预置入聚乳酸-聚羟基乙酸共聚物(Poly lactic acid co glycolic acid copolymer,PLGA)导管中,同时,以等量的达尔伯克(氏)改良伊格尔(氏)培养基(Dulbecco's Modified Eagle's medium,DMEM)代替EPI-NCSC作为对照,以用于修复大鼠坐骨神经10 mm距离的缺失。噻唑蓝(Methyl thiazolyl tetrazolium,MTT)比色分析结果显示,EPI-NCSC在PLGA膜上的初期粘附率为89.7%。在第1、3、5、7天细胞相对增殖率分别为89.3%、87.6%、85.6%和96.6%。细胞周期与DNA倍体分析表明,与PLGA共培养的EPI-NCSC与单独培养的EPI-NCSC相比较,二者的细胞周期变化趋势相同,增殖指数变化趋势也相同。在神经导管移植4周,术部实现了组织学水平的修复。大鼠手术一侧后肢感觉功能有所恢复,坐骨神经指数有所提高。研究结果表明,在PLGA导管中预置EPI-NCSC,有望实现较好的周围神经缺损的修复效果。     

碱性成纤维细胞生长因子对大鼠晚期周围神经再生作用的实验研究

目的探讨外源性碱性成纤维细胞生长因子(bFGF)对晚期周围神经再生的作用.方法50只SD大鼠随机分治疗组、对照组各25只,切断右侧坐骨神经,12周后予以修复,修复术后每日分别给予bFGF和生理盐水,行神经电生理和组织学检查.结果治疗组和对照组修复处远段神经均有不同程度再生,4周时已可见到再生轴突,且治疗组多见.计量分析治疗组运动神经传导速度、神经肌肉动作电位幅值、髓鞘厚度、再生轴突直径和截面积明显优于对照组.治疗组与对照组相比,差异有显著性.结论bFGF能促进晚期周围神经再生.     

Experimental Study of Low Dose Ultrashortwave Promoting Nerve Regeneration after Acellular Nerve Allografts Repairing the Sciatic Nerve Gap of Rats

Objectives To observe the effect of ultrashortwave (USW) therapy on nerve regeneration after acellular nerve allografts(ANA) repairing the sciatic nerve gap of rats and discuss its acting mechanisms. Methods Sixteen Wistar rats weighing 180–220 g were randomly divided into four groups with four rats in each group: normal control group; acellular group (ANA, treated by hypotonic-chemical detergent, was applied for bridging a 10 mm-long sciatic nerve defect); USW group (After 24 h of ANA repairing the sciatic nerve gap, low dose USW was administrated for 7 min, once a day, 20 times a course of treatment, three courses of treatment in all); and autografts group. 12 weeks after operation, a series of examinations was performed, including electrophysiological methods, the restoring rate of tibialis anterior muscle wet weight, histopathological observation (myelinated nerve number, myelin sheath thickness, and axon diameter), vascular endothelial growth factor (VEGF) mRNA expression of spinal cord, and muscle at injury site, and analyzed statistically. Results Compared to acellular nerve allografts alone, USW therapy can increase nerve conductive velocity, the restoring rate of tibialis anterior muscle wet weight, myelinated nerve number, axon diameter, VEGF mRNA expression of spinal cord, and muscle at injury site, the difference is significant. There were no differences between USW group and autografts group except myelin sheath thickness. Conclusions USW therapy can promote nerve axon regeneration and Schwann cells proliferation after ANA repairing the sciatic nerve gap of rats, the upregulation of VEGF mRNA expression of spinal cord and muscle may play an important role.     

神经生长因子药效学研究

目的考察神经生长因子对视神经损害的疗效。方法腹腔注射二硫化碳致视神经损害的大鼠模型,给药组球后注射或肌内注射神经生长因子,每天一次,每周6d,共计3周,空白对照组球后注射等量生理盐水,于治疗前后测定大鼠模式翻转（FREP）和闪光视觉诱发电位。结果球后注射高剂量组大鼠在治疗10d和20d时各波潜伏时比对照组有显著缩短,而球后注射低剂量组和肌内注射高剂量组大鼠于治疗10d时FVEP各波潜伏时也显著缩短,肌内注射低剂量组大鼠于治疗20d时FEP的P1和P2波潜伏时也显著或非常显著缩短。结论神经生长因子对大鼠视神经损害有明显的治疗作用。     

Acute Regulation of the Epidermal Growth Factor Receptor in Response to Nerve Growth Factor

PC12 cells possess specific receptors for both nerve growth factor and epidermal growth factor, and by an unknown mechanism, nerve growth factor is able to attenuate the propagation of a mitogenic response to epidermal growth factor. The differentiation response of PC12 cells to nerve growth factor, therefore, predominates over the proliferative response to epidermal growth factor. We have observed that the addition of nerve growth factor to PC12 cells rapidly produces a decrease in surface 125I-epidermal growth factor binding capacity. Unlike previously described nerve growth factor effects on 125I-epidermal growth factor binding capacity, which required several days of nerve growth factor exposure, the decreases we report occur within minutes of nerve growth factor addition: A 50% decrease in 125I-epidermal growth factor binding capacity is evident at 10 min. This rapid nerve growth factor response is concentration dependent; inhibition of 125I-epidermal growth factor binding is detectable at nerve growth factor levels as low as 0.2 ng/ml and is maximal at approximately 50 ng/ml, consistent with known ranges of biological activity. No demonstrable differences in the rate of epidermal growth factor receptor synthesis or degradation were observed in cells acutely exposed to nerve growth factor. Scatchard analysis revealed that acute nerve growth factor treatment decreased the number of both high- and low-affinity 125I-epidermal growth factor binding sites, while the receptor affinity remained unchanged. We have also investigated the involvement of various potential intracellular mediators of nerve growth factor action and of known intracellular modulatory systems of the epidermal growth factor receptor for their capacity to participate in this nerve growth factor activity.     

神经生长因子的发光免疫分析法

介绍了一种灵敏的神经生长因子化学发光免疫测定方法。小鼠神经生长因子（ｍＮＧＦ）的抗体ＩｇＧ用亲和层析纯化并用吖啶酯标记。该法可用于大鼠组织中ＮＧＦ含量的测定。方法的灵敏度为１０ｐｇ／ｍＬＮＧＦ;批内批间变异系数分别为８．７％及１３．２％;回收率平均为１０３％。ｍＮＧＦ抗体对人的ＮＧＦ也有极强的交叉反应,故本方法也可能用于病人血清或脑脊液中ＮＧＦ含量的测定。     

Regulation by Interleukin-1 of Nerve Growth Factor Secretion and Nerve Growth Factor mRNA Expression in Rat Primary Astroglial Cultures

Primary cultures of neonatal rat cortical astrocytes contain low cellular levels (about 2 pg/mg of protein) of nerve growth factor (NGF), but secrete significant amounts of NGF into the culture medium (about 540 pg of NGF/mg of cell protein/38-h incubation). Incubation of astrocytes with interleukin-1 (IL-1) increased the cellular content of NGF and the amount secreted by about threefold. In comparison, cerebellar astrocytes secreted significant amounts of NGF, and the secretion was also stimulated by IL-1. The stimulatory action of IL-1 on astrocytes prepared from cortex was dose- and time-dependent. Concentrations of IL-1 causing half-maximal and maximal stimulation of NGF secretion were 1 and 10 U/ml, respectively). Maximal NGF secretion induced by IL-1 (10 U/ml) was seen following 38 h of incubation. The basal secretion of NGF was reduced by about 50% under Ca2(+)-free conditions; however, the percent stimulation of NGF secretion by IL-1 was the same in the absence or presence of Ca2+. The stimulatory action of IL-1 was specific, because other glial growth factors and cytokines were almost ineffective in stimulating NGF secretion from cortical astroglial cells. IL-1 treatment also increased cellular NGF mRNA content twofold. The results indicate that IL-1 specifically triggers a cascade of events, independent of cell growth, which regulate NGF mRNA content and NGF secretion by astrocytes.     

Expression of Nerve Growth Factor and Nerve Growth Factor Receptor Genes in Human Tissues and in Prostatic Adenocarcinoma Cell Lines

Nerve growth factor (NGF) mRNAs were detected and quantified in a variety of normal and neoplastic human tissues by northern blot hybridization. Human heart contained the highest NGF mRNA levels, whereas lower but comparable levels were found in the placenta, prostate, and kidney. All tissues examined coexpressed the low-affinity NGF receptor (LNGFR), whereas none of these tissues expressed the high-affinity NGF receptor encoded by the trk protooncogene. The widespread distribution of the LNGFR suggests that it plays a role in the regulation of normal cell growth. No overexpression of NGF or LNGFR mRNA was detected in neoplastic tissues, whereas LNGFR-like immunoreactivity was localized outside of tumor cells. Transforming growth factor-alpha and protooncogene c-fos expression in these tissues did not show a systematic correlation with NGF/LNGFR expression. Furthermore, regulation of the human NGF gene was studied in DU145 cells, a prostatic adenocarcinoma cell line that synthesizes significant NGF mRNA levels. Serum induced, whereas dexamethasone inhibited, NGF mRNA synthesis in these cells. Serum induction was preceded by a rapid and transient activation of the c-fos protooncogene.     

Characteristics of Partially Purified Nerve Growth Factor Receptor

Receptors for the nerve growth factor protein (NGF) have been isolated from three cell types [embryonic chicken sensory neurons (dorsal root sensory ganglia; DRG), rat pheochromocytoma (PC12) and human neuroblastoma (LAN-1) cells] and have been shown to be similar with respect to equilibrium dissociation constants. The present results demonstrate that there are multiple molecular weight species for NGF receptors from DRG neurons and PC12 cells. NGF receptors can be isolated from DRG as four different molecular species of 228, 187, 125, and 112 kilodaltons, and PC12 cells as three molecular species of 203, 118, and 107 kilodaltons. The NGF receptors isolated from DRG show different pH-binding profiles for high- and low-affinity binding. High-affinity binding displays a bell-shaped pH profile with maximum binding between pH 7.0 and 7.9, whereas low-affinity binding is constant between pH 5.0 and 9.1, with a twofold greater binding at pH 3.6. At 22 degrees C, the association rate constant was found to be 9.5 +/- 1.0 X 10(6) M-1 s-1. Two dissociation rate constants were observed. The fast dissociating receptor has a dissociation rate constant of 3.0 +/- 1.5 X 10(-2) s-1, whereas the slow dissociating receptor constant was 2.4 +/- 1.0 X 10(-4) s-1. The equilibrium dissociation constants calculated from the ratio of dissociation to association rate constants are 2.5 X 109-11) M for the high-affinity receptor (type I) and 3.2 X 10(-9) M for the low-affinity receptor (type II). These values are the same as those determined by equilibrium experiments on the isolated receptors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nerve Growth Factor of Red Nucleus Involvement in Pain Induced by Spared Nerve Injury of the Rat Sciatic Nerve

Nerve growth factor (NGF), a member of the neurotrophin family, is essential for the development and maintenance of sensory neurons and for the formation of central pain circuitry. The current study was designed to evaluate the expression of NGF in the brain of rats with spared nerve injury (SNI), using immunohistochemical technique. The results showed that the level of NGF in the Red nucleus (RN) of SNI rats was apparently higher than that of sham-operated rats. To further study the effect of NGF in the development of neuropathic pain, different doses of anti-NGF antibody (20, 2.0 and 0.2 μg/ml) were microinjected into the RN contralateral to the nerve injury side of SNI rats. The data suggested that the higher doses of anti-NGF antibody (20 and 2.0 μg/ml) significantly attenuated the mechanical allodynia of neuropathic rats, while the 0.2 μg/ml antibody showed no analgesic effect. These results suggest that the NGF of RN is involved in the development of neuropathic allodynia in SNI rats.