体外培养神经干细胞CNTF、TGF-β1和IGF-1的表达

目的研究培养神经干细胞（NSC）中CNTF,TGF-β1,IGF-1基因表达情况.方法取小鼠胎鼠海马,分离纯化培养NSC,提取总RNA,RT-PCR技术检测CNTF,TGF-β1,IGF mRNA的表达情况.结果培养NSC中各因子mRNA均有表达;CNTF,TGF-β1表达较强,IGF-1表达较弱.结论体外培养的NSC表达CNTF,TGF-β1含量较高,可能是应用其治疗神经疾病的理论基础.     

Early changes of LIFR and gp130 in sciatic nerve and muscle of diabetic mice

Peripheral neuropathy is a common complication of diabetes mediated by alterations of growth factors. Members of the neuropoietic cytokine family, which include IL-6, LIF, and CNTF among others, have been shown to be important regulators of peripheral nerves and the muscles that they innervate. To investigate their potential role in diabetic nerve and muscle, we studied the expression of the shared receptor subunits, LIFR and gp130 in a mouse model of streptozotocin (STZ)-induced diabetes. The results of Western blotting and densitometric analysis showed that both LIFR and gp130 protein expression were increased in diabetic sciatic nerve compared to control mice at early time points following STZ injection. In diabetic gastrocnemius muscle, LIFR and gp130 were increased from 3 days to 24 weeks following STZ injection. In contrast, both LIFR and gp130 protein expression were decreased in diabetic soleus muscle at 3-days post-injection. Our results suggest that hyperglycemia results in changes to nerve and muscle soon after the onset of diabetes and that cytokines may play a role in this process.     

Neurotransmitter segregation: functional and plastic implications

Synaptic cotransmission is the ability of neurons to use more than one transmitter to convey synaptic signals. Cotransmission was originally described as the presence of a classic transmitter, which conveys main signal, along one or more cotransmitters that modulate transmission, later on, it was found cotransmission of classic transmitters. It has been generally accepted that neurons store and release the same set of transmitters in all their synaptic processes. However, some findings that show axon endings of individual neurons storing and releasing different sets of transmitters, are not in accordance with this assumption, and give support to the hypothesis that neurons can segregate transmitters to different synapses. Here, we review the studies showing segregation of transmitters in invertebrate and mammalian central nervous system neurons, and correlate them with our results obtained in sympathetic neurons. Our data show that these neurons segregate even classic transmitters to separated axons. Based on our data we suggest that segregation is a plastic phenomenon and responds to functional synaptic requirements, and to 'environmental' cues such as neurotrophins. We propose that neurons have the machinery to guide the different molecules required in synaptic transmission through axons and sort them to different axon endings. We believe that transmitter segregation improves neuron interactions during cotransmission and gives them selective and better control of synaptic plasticity.     

TGF-β1和CNTF在大鼠移植神经干细胞后的损伤脊髓中的表达

目的 研究在受损伤脊髓移植神经干细胞后对其TGF-β1和CNTF表达的影响.方法 将正常成年SD雌性大鼠35只,分为:单纯脊髓全横断组、假手术组、NSCs移植组.NSCs移植组在脊髓全横断后第7天时进行NSCs移植,其它2组不移植NSCs;通过RT-PCR测定脊髓损伤局部头侧在移植术后3,7,14 d TGF-β1和CNTF的表达.结果 移植术后3 d,7 d,单纯全横断组TGF-β的表达大于神经干细胞组.CNTF仅在术后7 d,前者表达大于后者,其余时间段2组间2因子的表达无统计学意义.结论 神经干细胞移植使脊髓损伤局部TGF-β1的表达降低,但对CNTF表达的影响不大.     

睫状神经营养因子对大鼠视神经不全损伤后轴浆运输的影响

目的探讨睫状神经营养因子(CNTF)对大鼠视神经(optic nerve, ON)中度不全损伤后轴浆运输的影响.方法成年雌性Wistar大鼠50只,用无创血管夹于球后1.5 mm钳夹ON 10 s,造成ON中度损伤,于伤后即刻、伤后1、2、4和8周CNTF治疗组玻璃体腔内注射人重组睫状神经营养因子(rhCNTF)2 μg,对照组注射等量双蒸水.分别在不同的时间(1、2、4、8和12周)应用辣根过氧化物酶(horseradish peroxidase, HRP)观察ON不全损伤后顺行轴浆运输的变化.结果伤后1～2周在损伤点后HRP顺染纤维度骤然下降,于上丘均未见HRP显色;伤后4周ON及上丘顺染密度逐渐增强至8周达高峰,对照组ON损伤远端顺染纤维度恢复至正常的12.87%,而治疗组至31.86%.两组间于ON损伤远端和上丘HRP顺染密度均有非常显著性差异(P<0.01).结论 CNTF可改善ON不全损伤后轴浆运输状况,促进ON结构的恢复.     

Effect of CNTF on ischaemic cell damage in rat hippocampus

Summary The neuroprotective effect of neurotrophic factors has been demonstrated in experimental cerebral ischaemia recently. These include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and basic fibroblast growth factor (basic FGF). The neuroprotective effect of ciliary neurotrophic factor (CNTF), however, has not been studied so far.We have examined the neuroprotective effect of recombinant rat CNTF in a rat forebrain ischaemia model. A continuous infusion of CNTF was started 1 week before the induction of ischaemia and continued until 1 week after the ischaemia. Reversible forebrain ischaemia was induced by 7 minutes of bilateral carotid occlusion with hypotension. Neuronal cell death in the hippocampal CA1 sector was evaluated 1 week after the ischaemia. For the control group artificial CSF (cerebrospinal fluid) was infused instead of CNTF.Per cent neuronal cell death was 83.4 ± 5.9% (mean ± SEM, n=5) in the control group, and 71.1 ± 10.0% (mean ± SEM, n=5) in the CNTF group. Although percentage of neuronal cell death was lower in the CNTF group, the difference was not statistically significant.This result suggests that the protective effect of CNTF in the rat forebrain ischaemia model may be limited compared with other neurotrophic factors. It is considered that the number of neurons protected by CNTF may be small.     

The great migration of bone marrow-derived stem cells toward the ischemic brain: therapeutic implications for stroke and other neurological disorders

Accumulating laboratory studies have implicated the mobilization of bone marrow (BM)-derived stem cells in brain plasticity and stroke therapy. This mobilization of bone cells to the brain is an essential concept in regenerative medicine. Over the past ten years, mounting data have shown the ability of bone marrow-derived stem cells to mobilize from BM to the peripheral blood (PB) and eventually enter the injured brain. This homing action is exemplified in BM stem cell mobilization following ischemic brain injury. Various BM-derived cells, such as hematopoietic stem cells (HSCs), mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs) and very small embryonic-like cells (VSELs) have been demonstrated to exert therapeutic benefits in stroke. Here, we discuss the current status of these BM-derived stem cells in stroke therapy, with emphasis on possible cellular and molecular mechanisms of action that mediate the cells' beneficial effects in the ischemic brain. When possible, we also discuss the relevance of this therapeutic regimen in other central nervous system (CNS) disorders.     

Effect of CNTF on low-affinity NGF receptor expression by cultured neurons from different rat brain regions.

Our previous work indicated that in E14 embryonic rat spinal cord cultures ciliary neuronotrophic factor (CNTF) exerted (1) a survival-promoting effect on motor neurons and on a large population of unidentified neurons, and (2) a regulatory role on the expression of ChAT and low affinity NGF receptor (LNGFR) in a population of small/medium-sized neurons. In the present study, we examined the effect of CNTF on the expression of LNGFR in cultures of different regions from the E18 embryonic rat brain, namely cortex, septum, striatum, mesencephalon, hippocampus, brainstem, and cerebellum. The number of LNGFR-positive neurons (stained with the 192-IgG monoclonal antibody) was determined in untreated cultures and in cultures treated for 6 days (0-6) with human recombinant CNTF. To distinguish between effects on survival and on LNGFR expression, experiments were performed in which CNTF was administered only for the last 48 h of the culture (from days 4-6). LNGFR positive neurons were found in the cultures of all the regions examined. In each one of them, CNTF increased the number of LNGFR-positive neurons by three- to fourfold after 6 days of treatment. In the striatum, septum, mesencephalon, and cerebellum, the effect of CNTF was shown to be on the regulation of LNGFR expression and not on survival. In cultures from the cortex, hippocampus and brainstem, a survival-promoting role of CNTF could be demonstrated. The effect of CNTF was dose dependent, with half-maximal effects (ED50) achieved at 2-4.5 TU/ml for all the brain regions. Maximal effects were reached at 100-250 TU/ml. From these results, we conclude that (1) there exists a wide spectrum of CNTF-responsive neurons in the central nervous system, and (2) CNTF plays an important and widespread role in regulating the expression of the LNGFR in neurons.     

大鼠脑血肿周围组织STAT 3的表达、细胞凋亡的变化与CNTF的影响

目的 观察大鼠脑血肿周围组织STAT3, Bcl-2, Caspase-3的表达情况,并探讨睫状神经营养因子(CNTF)对出血性脑卒中的治疗作用及其可能机制.方法 实验大鼠随机分为假手术组、模型组、CNTF治疗组,采用自体股动脉血注入大鼠尾壳核建立脑出血模型,CNTF治疗组于术后经尾静脉注射CNTF.分别于术后12h、24h、3d、5d 4个时间点取脑组织,应用免疫组化方法检测血肿周围组织STAT3, Bcl-2, caspase-3的表达情况.结果 CNTF治疗组大鼠脑血肿周围组织STAT3, Bcl-2的表达明显高于其他组,Caspase-3的表达水平比模型组低.结论 CNTF对脑出血后损伤神经细胞具有保护作用,其可能的机制为通过上调STAT3的表达,使Bcl-2的表达升高,从而减少出血灶周围细胞的凋亡.