实验性糖尿病周围神经病大鼠脊髓及背根神经节CGRP、VIP表达变化

目的通过观察糖尿病大鼠周围神经形态学的变化以及脊髓、背根神经节中降钙素基因相关肽(CGRP)、血管活性肠肽(VIP)表达变化,以探讨神经肽在糖尿病性神经病中所起的作用。方法Wistar大鼠模型的建立:采用腹腔一次性注射pH4.4枸橼酸钠缓冲液配制的1.25%链脲佐菌素(Streptozotocin STZ)制成糖尿病周围神经病大鼠。用ABC免疫组化方法观察8周和12周大鼠降钙素基因相关肽(CGRP)、血管活性肠肽(VIP)在脊髓及背根神经节的表达。结果糖尿病大鼠8周和12周时背根神经节、12周时脊髓CGRP、VIP表达下降(P<0.05),糖尿病大鼠脊髓8周时CGRP、VIP表达与正常大鼠比无明显差别。结论CGRP和VIP参与了糖尿病周围神经病的发病,糖尿病对大鼠背根神经节CGRP、VIP的表达影响更早。     

Receptors for vasoactive intestinal peptide on murine lymphocytes turn over rapidly

The interaction of the neuropeptide vasoactive intestinal peptide (VIP) with its receptors on murine mesenteric lymph node lymphocytes (MLN) has been re-examined in detail. Intact MLN actively internalize surface bound VIP. The rate constants associated with the insertion of receptors at the MLN surface, the internalization of VIP occupied and unoccupied receptors and the elimination of the peptide were determined. At 37 degrees C, MLN insert approximately 140 VIP receptors cell-1 min-1 at their surface, and the rate of internalization of occupied receptors (0.23 min-1) was much greater than that of the unoccupied receptors (0.02 min-1). Exposure of MLN to non-saturating concentrations of VIP markedly altered the expression of VIP receptors at the lymphocyte surface. The rapid turnover of VIP receptors combined with the differential clearance of occupied and unoccupied receptors from the cell surface provides a mechanism by which homologous regulation of VIP receptor expression can occur on these lymphocytes.     

The effects of aging on mu and delta opioid receptors in the spinal cord of Fischer-344 rats

Previous research has demonstrated that the antinociceptive efficacy of opioids decreases with advancing age. This study utilized radioligand binding techniques to determine if this decline is due to a change in the receptor density (B_max) and/or affinity (measured as K_d) of the mu (μ) and/or delta (δ) opioid receptors in the spinal cord with advancing age. Saturation binding analysis with [³H][ -Ala²,N-methyl-Phe⁴,Gly⁵-ol]enkephalin (DAMGO: a μ-opioid selective agonist) and [³H]naltrindole (a δ-opioid selective antagonist) revealed no age-related changes in B_max for either the μ or δ-opioid receptors. The K_d value for naltrindole was likewise unaffected by age. The K_d value for DAMGO however, was significantly higher in the aged group as compared with the young and mature groups, indicating a decreased affinity of spinal μ-opioid receptors for DAMGO.     

The Role of Vasoactive Intestinal Peptide (VIP) in Megakaryocyte Proliferation

Megakaryocytopoiesis is a multistage process that involves differentiation of hematopoietic stem cells through the myeloid lineage, ultimately producing megakaryocytes and platelets. Vasoactive intestinal peptide (VIP) stimulates adenylate cyclase and induces differentiation in multiple cell types; VIP is expressed in hematopoietic stem cells and in megakaryocytes, but its function in these cells has not yet been delineated. The present study was designed to investigate whether the type 1 VIP receptor, VPAC1, mediates VIP effects on megakaryocytopoiesis. The human megakaryoblastic leukemia cell line (CMK) was transfected with VPAC1 and the transgene expression was confirmed by qualitative polymerase chain reaction and immunohistochemistry. The rate of proliferation and the patterns of differentiation were then compared for CMK and CMK/VPAC1 through multiple growth cycles. Upregulation of VPAC1 expression resulted in a decreased proliferation rate (p = 0.0003) and enhanced differentiation with CMK/VPAC1 cells having twice the cell surface area of control CMK cells (p = 0.001), thus increasing potential for proplatelet formation. These results suggest that VIP acts in an autocrine fashion via VPAC1 to inhibit megakaryocyte proliferation and induce proplatelet formation.     

胚胎脊髓移植在恢复损伤脊髓传导功能中的作用

目的：探讨胚胎脊髓移植在恢复损伤脊髓传导功能中的作用。方法：将Ｅ１４胚胎脊髓植入成鼠损伤脊髓后３０、４５、６０天时，用单位放电记录技术观察了正常脊髓神经元和移植物神经元的自发放电活动，及其对刺激坐骨神经、红核和同时刺激的反应。结果：正常脊髓神经元的自发单位放电多是一个低频的单发脉冲活动。无论选择那种刺激方式，都可见兴奋、抑制和无反应三种反应。术后３０天时，胚胎神经元的自发单位放电以高频电脉冲活动为主，簇状放电所占比例较大，对刺激有反应的放电单位数也较少；随着动物存活时间的延长，这些单位放电的情况逐渐向着低频、单脉冲以及高反应率的方向发展。至术后６０天时，胚胎神经元单位放电的频率、形式以及对刺激的反应情况都变得和正常神经元的相似。结论：胚胎神经元移植后经历了一个逐渐发育分化过程，在这个过程中它们有可能逐渐和宿主神经元形成了功能性突触连接。     

Evidence that local non-NMDA receptors contribute to functional deficits in contusive spinal cord injury

To investigate the role of (non-NMDA) types of excitatory amino acid (EAA) receptors in traumatic spinal cord injury, we administered 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)-quinoxaline (NBQX), a potent and specific antagonist of non-NMDA receptors, to rats with a standardized contusive spinal cord injury. Focal infusion of NBQX into the injury site significantly reduced long-term hindlimb functional deficits as well as decreasing the time required for the rats to establish a reflex bladder. The results suggest that non-NMDA receptors at or near the injury site are involved in producing a portion of the functional deficits that result from contusive spinal cord injury.     

Cholinergic regulation of VIP gene expression in human neuroblastoma cells

The effects of carbamylcholine (CCh) on the gene expression of the neuropeptide vasoactive intestinal polypeptide (VIP) were studied using two human neuroblastoma cell lines, NB-1 and BE(2)M17. CCh caused a fast increase in VIP mRNA level in both cell lines which was followed by an increase in VIP immunoreactivity. The time-course of the induction of both mRNA and peptide differed, however, between the two cell lines. No morphological changes of the cells were observed during 6 days of stimulation. The effect was mediated by the muscarinic class of acetylcholine receptors, since it could be totally abolished by atropine. Since CCh caused an accumulation of inositol-1,4,5-triphosphate, it is likely that muscarinic receptor subtype M1, M3 or M5 is involved. Experiments with the translational inhibitor, cycloheximide, showed that CCh mediated a direct effect on the VIP gene expression. By combining gel permeation chromatography with radioimmunoassays using antisera specific for the various VIP-precursor products, immunoreactive peaks eluting as the synthetic peptides were found in both cell lines. In addition, earlier eluting peaks which could represent partially processed or extended VIP forms were found. After CCh induction the concentration of all preproVIP-derived products increased, and there was a tendency towards a shift to more fully processed VIP. The findings give new evidence for a direct regulation of VIP gene expression in human neuronal cells by cholinergic agents.     

大鼠脊髓少突胶质前体细胞的培养与鉴定方法

目的 探讨大鼠脊髓少突胶质前体细胞（OPCs）的分离纯化及诱导分化方法.方法 取出生后3d内SD大鼠脊髓,采用0.125％胰蛋白酶消化获取原代混合胶质细胞,培养10 d左右在37℃恒温摇床采取180 r/min摇速振摇并差速贴壁40 min获得纯化的OPCs;取纯化后培养3d的OPCs免疫荧光鉴定细胞纯度或诱导分化.结果 采用胰蛋白酶消化法获取原代混合胶质细胞、振摇并差速贴壁法分离纯化能够得到纯度较高的OPCs,折光性强,呈双极或三极形态,免疫荧光染色显示95％细胞表达A2B5和NG2（OPCs标志物）,经诱导分化后表达O4及MBP（少突胶质细胞标志物）.结论 采用振摇差速贴壁法可从大鼠脊髓中分离纯化获得高纯度的OPCs,获得的OPCs体外生长稳定,经诱导可分化为成熟的少突胶质细胞.     

嗅鞘细胞移植治疗脊髓损伤的临床研究现状

目的：对嗅鞘细胞生物学特性、培养纯化、嗅鞘细胞移植的可能机制及嗅鞘细胞移植在临床的应用等方面进行分析,介绍嗅鞘细胞移植治疗脊髓损伤的研究现状。 资料来源：以olfactory ensheathing cells,spinal cord injury,嗅鞘细胞,脊髓损伤为检索词检索PubMed数据库(2000/2009),中国期刊全文数据库(2000/2009)。 资料选择：纳入标准：①文章所述内容应与嗅鞘细胞及脊髓损伤密切相关。②同一领域选择近期发表或在权威杂志上发表的文章。排除标准：①重复性研究。②Meta分析。 结局评价指标：嗅鞘细胞移植治疗脊髓损伤的研究进展。 结果：嗅鞘细胞具有与许旺细胞和星形胶质细胞相似的特征。目前嗅鞘细胞移植的动物实验主要致力于提高轴突再生能力、替代细胞成分、阻止脱髓鞘病变和促进髓鞘再生等方面,移植的嗅鞘细胞具有促进感觉及运动功能恢复的客观结果,有些移植研究甚至已经进入了临床试验阶段。不过嗅鞘细胞移植由动物实验转化到临床应用还受到很多因素的影响,诸如移植剂量、细胞生长因子的活力,细胞移植的风险等,尤其是嗅鞘细胞移植后的近期及远期效果还需要进一步深入研究、评价,并且需要长时间的随访。有研究已经把用基因转染的嗅鞘细胞用于移植,在动物试验身上已经取得了满意的效果。 结论：随着基因工程技术发展以及嗅鞘细胞移植修复神经机制的深入研究,嗅鞘细胞移植必将为临床治疗脊髓损伤的患者带来康复的希望。     

A non-opioid pathway for dynorphin-caused spinal cord injury in rats

Intrathecal injection of dynorphin into rats via subarachnoid catheter induces damage to spinal cord tissue and motor function. Injection of the kappa opioid receptor antagonist nor-binaltorphine, or the excitatory amino acid N-methyl-D-aspartate receptor antagonist MK-801 into rats alleviated the pathological changes of dynorphin-caused spinal cord tissue injury and reduced the acid phosphatase activity in the spinal cord. The experimental findings indicate that there are opioid and non-opioid pathways for dynorphin-induced spinal cord injury, and that the non-opioid receptor pathway may be mediated by the excitatory amino acid N-methyl-D-aspartate receptor.     

Neuropeptides as growth and differentiation factors in general and VIP in particular

During the course of neurodevelopment a large population of neurons die normally (Berg, 1982; Oppenheim et al., 1989). Are neuropeptides involved in the regulation of neuronal survival, maturation, and maintenance? The peptides are an ever growing family of neuroactive agents and this review shall emphasize VIP (vasoactive intestinal peptide [Said and Mutt, 1970; Gozes and Brenneman, 1989]), which has been shown to be involved in maturation, growth, and maintenance of neurons (Brenneman et al., 1985a, 1987, 1988, 1990, 1990b; Brenneman and Eiden, 1986; Brenneman and Nelson, 1986). Comparative actions of other neuropeptides will also be discussed.     

室管膜细胞在大鼠脊髓损伤后的反应性增生

目的旨在探讨成年大鼠脊髓损伤后室管膜细胞的增殖反应,为进一步促进脊髓损伤后自身修复提供理论依据。方法应用动脉瘤夹压迫建立大鼠脊髓压迫损伤模型,通过组织病理学及免疫组织化学方法检测不同时段室管膜细胞的反应性增生和神经外胚层多潜能细胞特异性抗原巢蛋白(nestin)的表达。结果常规病理学检查显示损伤模型类似于临床常见的脊髓横贯伤,损伤后24h可以观察到室管膜细胞nestin表达明显升高,增殖细胞核抗原(PCNA)呈阳性;1周后见室管膜细胞显著增生;nestin的表达随时间进展呈向下调节。结论静止的室管膜细胞有潜在的增殖能力,在脊髓损伤后表现出明显的分裂增生,可能在结构和功能重塑过程中起作用。     

The expression of nerve growth factor receptor on Schwann cells and the effect of these cells on the regeneration of axons in traumatically injured human spinal cord

To investigate the effects of Schwann cells and nerve growth factor receptor (NGFR) on the regeneration of axons, autopsy specimens of spinal cord from 21 patients with a survival time of 2 h to 54 years after spinal cord trauma were studied using immunohistochemistry and electron microscopy. Regenerating sprouts of axons could be observed as early as 4 days after trauma. At 4.5 months after trauma, many regenerating nests of axons appeared in the injured spinal cord. The regeneration nests contained directionally arranged axons and Schwann cells. Some axons were myelinated. In injured levels of the spinal cord, the Schwann cells exhibited an increased expression of NGFR within spinal roots. These results show that an active regeneration process occurs in traumatically injured human spinal cord. The NGFR expressed on Schwann cells could mediate NGF to support and induce the axon regeneration in the central nervous system. Received: 20 June 1995 / Revised, accepted: 18 September 1995     

Effects of opioid receptor antagonists on the effects of i.v. morphine on carrageenin evoked c-Fos expression in the superficial dorsal horn of the rat spinal cord

This study performed in freely moving rats evaluated the ability of specific opioid receptor antagonists to reverse the inhibitory effects of morphine on carrageenin-induced c-Fos expression in the spinal cord. Our study focused on the superficial dorsal horn (laminae I-II), which is the main termination site of nociceptive primary afferent fibers and is rich in opioid receptors. In order to replicate clinical routes of administration, all agents were administered intravenously (i.v.). As previously demonstrated, pre-administered i.v. morphine (3 mg/kg) produced a marked decrease (58+/-5%) in the number of Fos-LI neurones measured at 2 h after intraplantar (i.pl.) carrageenin (6 mg/150 microl) and yet was without influence on peripheral oedema. This decrease in c-Fos expression was completely blocked by combined administration of morphine with the mu-opioid receptor antagonist, [D-Phe-Cys-Tyr-D-Orn-Thr-Pen-Thr-NH2] (CTOP-1+1 mg/kg). Naltrindole (NTI-1+1 mg/kg), a delta-opioid receptor antagonist partially blocked the effects of systemic morphine, so that the inhibitory effects of morphine after NTI injection are now 40+/-4%. However, this effect of NTI was weak since the depressive effects of morphine were still highly significant (p<0.001). In contrast, nor-binaltorphimine (nor-BNI-1+1 mg/kg), a kappa-opioid receptor antagonist, had no significant effect on the effects of morphine. These results indicate the major contribution of mu-opioid receptors to the antinociceptive effects of systemic morphine at the level of the superficial dorsal horn. The observed effect of NTI is not necessarily related to a direct action of morphine on delta-opioid receptors and some possible actions of this antagonist are discussed.     

The effects of interleukin-1 receptor antagonist protein (IRAP) infusion following spinal cord transection in rats

A laminectomy was performed at the T5−T6 vertebral level in adult, male, Sprague-Dawley rats and the spinal cord transected with a scalpel. A group of sham animals was subjected to the same surgery without the transection step. A group of unhandled control rats was also included. A subgroup of transected animals received a subcutaneous osmotic minipump that dispensed IL-1 receptor antagonist protein (IRAP) at the transection site for 7 consecutive days. Another transected subgroup received a minipump that infused the vehicle only. IRAP-treated rats displayed a significant reduction in body temperature (p<0.05) compared with vehicle-treated rats. The IRAP-treated rats were also less active when assessed for locomotor behavior using an HVS computerized tracking system (p<0.01). IRAP treatment had no effect on serum corticosterone, β-endorphin levels, Con A, PHA, or LPS-induced splenocyte mitogenesis when compared with vehicle-treated animals. However, half of the IRAP-treated animals exhibited a substantive reduction in the number of reactive astrocytes near the transection site, suggesting a possible effect of IRAP on astrocyte activation.     

腺苷A1受体激动剂对缺血损伤的兔脊髓神经元凋亡的影响

目的观察腺苷A1受体激动剂对脊髓缺血性损伤后的神经元凋亡的影响。方法建立兔脊髓缺血模型,给予腺苷A1受体激动剂(CPA),观察兔神经功能恢复,通过病理切片,计算脊髓前角正常神经元,再应用免疫荧光染色检测BCL-2表达水平,western-blot的方法观察caspase3、caspase9、BCL-2、BCL-X1、BAX、BAD表达水平。结果与DMSO组相比,CPA组兔神经功能明显改善。caspase3、caspase9、BCL-2、BCL-X1表达水平显著高于DMSO组,而BAX、BAD表达水平则明显降低。结论腺苷A1受体激动剂可能通过抑制神经元凋亡对脊髓缺血损伤发挥保护作用。     

Upregulation of Group I metabotropic glutamate receptors in neurons and astrocytes in the dorsal horn following spinal cord injury

Of the glutamate receptor types, the metabotropic glutamate receptors (mGluRs) are G proteins coupled and can initiate a number of intracellular pathways leading to hyperexcitability of spinal neurons. In this study, we tested the expression of mGluRs to determine which cell types might contribute to sustained neuronal hyperexcitability in the lumbar enlargement with postoperative day (POD) 7 (early), 14 (late), and 30 (chronic phase) following spinal cord injury (SCI) by unilateral hemisection at T13 in Sprague-Dawley rats. Expression was determined by confocal analyses of immunocytochemical reaction product of neurons (NeuN positive) and astrocytes (GFAP positive) in the dorsal horn on both sides of the L4 segment. Neurons were divided into two sizes: small (<20 microm) and large (>35 microm), for physiological reasons. We report a significant increase of mGluR(1) expression in large and small neurons of the dorsal horn on both sides of the cord in late and chronic phases when compared to control sham groups. Expression of mGluR(2/3) significantly increased in large neurons on the ipsilateral (hemisected) side in the late phase. Expression of mGluR(5) significantly increased in large neurons in early, late, and chronic phases. In addition, mGluR(1) and mGluR(5) expression after hemisection was significantly increased in astrocytes in early, late, and chronic phases; whereas mGluR(2/3) did not display any significant changes. In conclusion, our data demonstrate long-term changes in expression levels of Group I mGluRs (mGluR(1) and mGluR(5)) in both neurons and astrocytes in segments below a unilateral SCI. Thus, permanent alterations in dorsal horn receptor expression may play important roles in transmission of nociceptive responses in the spinal cord following SCI.     

Transplantation of olfactory ensheathing cells or Schwann cells restores rapid and secure conduction across the transected spinal cord

Olfactory ensheathing cells (OECs) or Schwann cells were transplanted into the transected dorsal columns of the rat spinal cord to induce axonal regeneration. Electrophysiological recordings were obtained in an isolated spinal cord preparation. Without transplantation of cells, no impulse conduction was observed across the transection site; but following cell transplantation, impulse conduction was observed for over a centimeter beyond the lesion. Cell labelling indicated that the regenerated axons were derived from the appropriate neuronal source, and that donor cells migrated into the denervated host tract. As reported in previous studies, the number of regenerated axons was limited. Conduction velocity measurements and morphology indicated that the regenerated axons were myelinated, but conducted faster and had larger axon areas than normal axons. These results indicate that the regenerated spinal cord axons induced by cell transplantation provide a quantitatively limited but rapidly conducting new pathway across the transection site.     

Spinally-mediated behavioural responses evoked by intrathecal high-dose morphine: possible involvement of substance P in the mouse spinal cord

Intrathecal (i.t.) administration of morphine in the spinal subarachnoid space of mice produced a severe hindlimb scratching followed by biting and licking. The onset of the scratching behaviour was observed 60–70 s after i.t. injection of morphine (60 and 90 nmol), and had a duration of 3–4 min. The morphine-induced behaviour was increased additively by i.t. co-administration of substance P (SP). This characteristic behavioural response was inhibited dose-dependently by i.t. co-administration of the tachykinin NK-1 receptor antagonists, sendide and CP-96,345. Significant antagonistic effects of SP (1–7), a putative antagonist for NK-1 receptors and [d-Phe⁷,d-His⁹jSP (6–11), a selective antagonist for SP receptors, were observed against the morphine-induced behaviour. Pretreatment with i.t. SP antiserum and i.t. capsaicin resulted in reduction of the response to morphine. I.t. administration of somatostatin (SOM) antiserum, cysteamine, a relatively selective depletor of SOM and cyclo-SOM, a SOM receptor antagonist, produced no inhibitory effect on the morphine-induced behaviour. These results demonstrate that a spinal system of neurones containing SP may be involved in elicitation of the behavioural episode following i.t. injection of morphine in mice.