大鼠骨髓间充质干细胞向神经细胞分化过程中Notch信号与RhoA/Rho激酶信号的协同作用

目的 探讨Notch信号通路在大鼠骨髓间充质干细胞(MSCs)向神经细胞分化中与RhoA/Rho激酶信号的协同作用.方法 实验分为无血清培养基对照组和盐酸法舒地尔组.采用盐酸法舒地尔诱导大鼠MSCs分化为神经细胞.RT-PCR检测Hes1的表达变化;免疫细胞化学法检测神经元特异性烯醇化酶(NSE)、神经微丝蛋白亚单位(NF-M)和胶质纤维酸性蛋白(GFAP)的表达变化.结果 ①盐酸法舒地尔组MSCs的Hes1 mRNA转录下降(P<0.05).②盐酸法舒地尔可以诱导MSCs向神经细胞分化,NSE、NF-M的阳性表达率显著高于无血清培养基组(P<0.05).结论 盐酸法舒地尔在诱导大鼠MSCs向神经细胞分化过程中,可能存在Notch信号通路与RhoA/Rho激酶通路信号的协同作用,共同促进MSCs向神经细胞分化. Abstract： Objective To investigate the cross-talk between notch and Rho/Rho GTPase signaling on rat bone marrow mesenchymal stem cells differentiating into neurons. Methods The experiments were divided into serum-free medium control group and fasudil hydrochloride group. Fasudil hydrochloride induces MSCs differentiating into neurons. The expression of Hes1 mRNA was detected by RT-PCR. The expression of neuron-specific enolae(NSE), neurofilament M (NF-M) and glial fibrillary acidic protein (GFAP)was detected by immunocytochemical method. Results ①The Hes1 mRNA expressed by MSCs of fasudil hydrochloride group was significantly decreased(P<0.05).②Fasudil hydrochloride can induce MSCs differentiating into neurons and there was higher expression of neuron-specific enolae(NSE) and neurofilament-M (NF-M) than the serum-free medium control group(P<0.05).Conclusions There may be cross-talk between notch signaling and RhoA/Rho GTPase signaling on differentiation of rat bone marrow stromal cell into neurons induced by fasudil hydrochloride and they jointly promoted the differentiation of MSCs into neurons.     

海人酸活化的小胶质细胞H_2O_2、NO的分泌对海马神经元谷氨酸含量的影响

目的:初步探讨海人酸(KA)活化培养的新生SD大鼠小胶质细胞(MG)及其分泌的一氧化氮/过氧化氢(NO/H2O2)、海马神经元、谷氨酸(Glu)之间的相互关系。方法:以KA作为MG的激活剂,以一氧化氮合成酶(NOS)的抑制剂氨基胍(AG)或过氧化氢的水解酶(CAT)作为工具药,先检测原代分离纯化培养的MG在KA激活后及工具药作用后各组条件培养液中NO和H2O2含量的变化,再用各组小胶质细胞条件培养液孵育离体海马神经元,观察其对神经元内Glu表达的影响。结果:KA作用后各组条件培养液中NO和H2O2含量明显升高,经AG或CAT处理后各组条件培养液中NO和H2O2含量显著降低;海马神经元的Glu免疫反应性KA组较对照组明显增强,在AG+KA组和CAT+KA组较KA组明显减弱。结论:活化的MG可能通过氧化损伤机制作为参与癫痫发作一个重要环节,提示采取抑制小胶质细胞活化、减少氧化损伤也可能是癫痫防治研究的一个重要方向。     

雷公藤内酯醇对匹罗卡品致痫大鼠海马神经元的保护性研究

目的研究雷公藤内酯醇对颞叶癫痫大鼠海马神经元的保护作用及其机制。方法随机将70只生后21 d的雄性Wistar大鼠分为空白对照组10只,癫痫组及雷公藤内酯醇干预组各30只。采用Nissl、FJB染色法观察海马神经元的损伤变化;采用免疫组化法检测海马组织中星形胶质细胞标志物胶质纤维酸性蛋白(GFAP)和小胶质细胞标志物钙离子结合适配器分子1(IBa-1)的表达状况。结果与空白对照组相比,癫痫组和药物干预组海马神经元损伤明显,GFAP、IBa-1呈高表达;与癫痫组相比,药物干预组海马神经元的损伤较小,GFAP及IBa-1表达较低。结论雷公藤内酯醇对癫痫持续状态后海马神经元的损伤有保护性作用,其作用机制可能与雷公藤内酯醇抑制胶质细胞活化抵抗脑内炎症反应有关。     

半胱氨酰白三烯受体1拮抗剂孟鲁司特对缺血性损伤后神经元形态的作用

目的:观察半胱氨酰白三烯受体1拮抗剂孟鲁司特对原代神经元缺血性损伤后形态变化的作用。方法:在不同浓度孟鲁司特存在条件下,以缺氧缺糖(OGD)2 h和再灌(R)24 h(OGD/R)诱导大鼠原代神经元及皮层混合培养细胞的神经元损伤;以免疫染色法检测神经元数量、胞体大小、胞体总神经突起数量、一级神经突起数量、长度及其分支数量等指标,观察神经元形态的变化。结果:OGD/R可明显减少神经元的数量,显著改变神经元的形态。而孟鲁司特(0.0001～1μmol/L)能减轻单独神经元培养中OGD/R诱导的神经元数量减少,抑制一级神经突起分支数量增加;在混合培养中,孟鲁司特(0.0001～0.1μmol/L)增加OGD/R后一级神经突的长度,减少神经突起数量以及一级神经突起分支数量。结论:半胱氨酰白三烯受体1拮抗剂孟鲁司特对大鼠原代神经元缺血性损伤有保护作用。     

Complement in the brain

The brain is considered to be an immune privileged site, because the blood-brain barrier limits entry of blood borne cells and proteins into the central nervous system (CNS). As a result, the detection and clearance of invading microorganisms and senescent cells as well as surplus neurotransmitters, aged and glycated proteins, in order to maintain a healthy environment for neuronal and glial cells, is largely confined to the innate immune system. In recent years it has become clear that many factors of innate immunity are expressed throughout the brain. Neuronal and glial cells express Toll like receptors as well as complement receptors, and virtually all complement components can be locally produced in the brain, often in response to injury or developmental cues. However, as inflammatory reactions could interfere with proper functioning of the brain, tight and fine tuned regulatory mechanisms are warranted. In age related diseases, such as Alzheimer's disease (AD), accumulating amyloid proteins elicit complement activation and a local, chronic inflammatory response that leads to attraction and activation of glial cells that, under such activation conditions, can produce neurotoxic substances, including pro-inflammatory cytokines and oxygen radicals. This process may be exacerbated by a disturbed balance between complement activators and complement regulatory proteins such as occurs in AD, as the local synthesis of these proteins is differentially regulated by pro-inflammatory cytokines. Much knowledge about the role of complement in neurodegenerative diseases has been derived from animal studies with transgenic overexpressing or knockout mice for specific complement factors or receptors. These studies have provided insight into the potential therapeutic use of complement regulators and complement receptor antagonists in chronic neurodegenerative diseases as well as in acute conditions, such as stroke. Interestingly, recent animal studies have also indicated that complement activation products are involved in brain development and synapse formation. Not only are these findings important for the understanding of how brain development and neural network formation is organized, it may also give insights into the role of complement in processes of neurodegeneration and neuroprotection in the injured or aged and diseased adult central nervous system, and thus aid in identifying novel and specific targets for therapeutic intervention.     

亚低温辅助治疗对急性重型颅脑损伤患者外周血神经元特异性烯醇化酶、一氧化氮和C反应蛋白水平的影响

目的探讨亚低温治疗对急性重型颅脑损伤患者外周血神经元特异性烯醇化酶（NSE）、一氧化氮（NO）和C反应蛋白（CRP）水平的影响。方法将90例急性重型颅脑损伤患者随机分为对照组（n=45）和观察组（n=45）。两组均给予常规治疗,观察组联合亚低温辅助治疗。观察治疗前后两组患者的外周血神经元特异性烯醇化酶（neuronspecific enolase,NSE）、一氧化氮（nitric oxide,NO）和C反应蛋白（C-reactive protein,CRP）水平变化。结果观察组预后良好率和病死率分别为46.67%（21/45）和11.11%（5/45）,明显优于对照组的28.89%（13/45）和24.44%（11/45）（P〈0.05）。治疗后第3、5天和复温后（第7天）观察组NSE、NO和CRP水平均明显低于对照组（P〈0.05）。结论亚低温辅助治疗急性重型颅脑损伤的疗效显著,可有效降低NSE、NO和CRP的水平,减轻脑组织的继发性损伤,降低病死率,改善预后。     

The simulated microgravity enhances the differentiation of mesenchymal stem cells into neurons

Growing evidence shows that physical microenvironments and mechanical stresses, independent of soluble factors, help influence mesenchymal-stem-cell fate. rMSCs (rat mesenchymal stem cells) present spread, spindle shape when cultured in normal gravity (NG) while in simulated microgravity (SMG) they become unspread, round shape. Here we demonstrate that simulated microgravity can enhance the differentiation of mesenchymal stem cells into neurons, which might be a new strategy for the treatment of central nervous system diseases. rMSCs were cultured respectively in normal gravity and in a clinostat to simulate microgravity, followed with neuronal differentiated medium. The neuronal cells derived from rMSCs in SMG express higher microtubule-associated protein-2 (MAP-2), tyrosine hydroxylase (TH) and choline acetyltransferase (CHAT). Furthermore, as rMSCs are subjected to SMG, they excrete more neurotrophins like nerve growth factor (NGF), brain derived neurophic factor (BDNF) and ciliary neurotrophic factor (CNTF). Neuronal cells from SMG group generated more mature action potentials and displayed repetitive action potentials by comparison to cells from NG group. We conclude that simulated microgravity can enhance the differentiation of mesenchymal stem cells into neurons.     

JNK regulates FoxO-dependent autophagy in neurons

The cJun N-terminal kinase (JNK) signal transduction pathway is implicated in the regulation of neuronal function. JNK is encoded by three genes that play partially redundant roles. Here we report the creation of mice with targeted ablation of all three Jnk genes in neurons. Compound JNK-deficient neurons are dependent on autophagy for survival. This autophagic response is caused by FoxO-induced expression of Bnip3 that displaces the autophagic effector Beclin-1 from inactive Bcl-XL complexes. These data identify JNK as a potent negative regulator of FoxO-dependent autophagy in neurons.     

小鼠神经元中CCK8与EGF协同作用的初步研究

目的: 探讨八肽胆囊收缩素(CCK₈)与表皮生长因子(EGF)在神经元信号转导中的交叉对话(cross-talk)及可能存在机制,并对CCK₈与EGF的协同作用进行初步研究。方法: CCK₈刺激表皮生长因子受体(EGFR)磷酸化的受体类型分析:培养的乳小鼠神经元随机分为对照组(等量的DMEM培养基)、CCK₈刺激组(10^-7 mol/L)、CCK_A受体拮抗剂L364 718组、CCK_B受体拮抗剂L365 260组以及L364 718+L365 260联合组(浓度均为10^-8 mol/L),拮抗剂加入10 min后再给予CCK₈,作用5 min后收集细胞提取蛋白,Western blotting检测磷酸化表皮生长因子受体(p-EGFR)蛋白表达量的变化;CCK₈与EGF对神经元EGFR磷酸化状态的影响和CCK₈与EGF协同作用功效分析:培养的乳小鼠神经元随机分为对照组、CCK₈(10^-7 mol/L)组、EGF(40 μg/L)组以及CCK₈+EGF组,药物作用5 min后终止反应,处理和分析方法同前,同时通过MTT法检测各组神经元培养不同时间(24、48、72、96 h)后细胞的生长活性。结果: (1)2种CCK受体拮抗剂均可降低EGFR蛋白的磷酸化水平,其中A型受体拮抗剂的作用明显强于B型,2种拮抗剂同时作用对EGFR蛋白磷酸化水平的降低作用更为明显;(2)CCK₈和EGF分别刺激神经元后,EGFR的磷酸化水平均增强,但CCK₈+EGF刺激后表现更为显著;(3)CCK₈与EGF联用对增强神经元生长活性和延长其存活时间的作用较两药单独作用效果更为明显(P<0.05)。结论: (1)CCK_A和CCK_B受体均介导了CCK₈激活EGFR磷酸化的信号转导途径,但A型受体发挥了更为重要的作用;(2)CCK₈与EGF信号转导途径之间存在着cross-talk;(3)CCK₈与EGF可能通过信号转导的cross-talk协同促进小鼠神经元的生长与存活。     

腺相关病毒介导胰岛素样生长因子I对高糖诱导神经元凋亡的保护作用

目的研究重组腺相关病毒（AAV）载体介导胰岛素样生长因子I（IGFI）在体外神经元表达的情况,及其对高糖诱导神经元凋亡的保护作用。方法利用分子克隆技术将大鼠IGFI基因克隆到pSNAV2．0质粒上,构建包含重组质粒pSNAV2．0-IGFI的杂合型重组AAV载体rAAV2／1-IGFI。将人神经母细胞瘤SH—SY5Y细胞分为正常组（A组）、无血清组（B组）、无血清高糖组（C组）,无血清高糖＋rAAV2／1-IGFI组（D组）,其中A组不做任何处理;B组使用无血清培养基培养;C组用含100mmol／LD．葡萄糖的无血清培养基培养;D组则先用rAAV2／1-IGFI病毒载体感染后再用含100mmol／LD．葡萄糖的无血清培养基处理。干预24h后应用RT—PCR和Western免疫印迹检测各组IGFI基因和蛋白的表达情况;应用Hoechst 33342荧光染色法、AnnexinV—FITC／PI双染法流式细胞仪检测细胞凋亡。观察rAAV2／1-IGFI感染后对高糖诱导SH—SY5Y细胞凋亡的保护作用。结果成功构建rAAV2／1-IGFI重组AAV载体。感染SH-SY5Y细胞后,RT—PCR显示SHSY5Y能表达大鼠IGFI基因;Western免疫印迹检测发现D组IGFI蛋白的表达水平（0．44±0．04）显著高于其他3组（A组0．29±0．02,B组0．17±0．02,C组0．08±0．02,均P〈0．05）。rAAV2／1-IGFI能明显降低高糖诱导细胞凋亡的凋亡率：Hoechst33342荧光染色检测总凋亡率分别为A组（2．71±1．03）％,B组（9．17±1．72）％,C组（25．63±1．81）％,D组（14．50±2．27）％,各组间差异均有统计学意义（P〈0．05）;流式细胞仪分析结果表明Annexin V-FITC^＊／PI^-的早期凋亡细胞加上Annexin V—FITC^＊／PI^＊的晚期凋亡细胞的总细胞凋亡率A组为（5．01±1．17）％,B组为（9．87±1．38）％,C组为（27．56±2．25）％,D组为（17．34±2．08）％,各组间差异均有统计学意义（P〈0．05）。结论rAAV2／1-IGFI感染体外神经元SH—SY5Y细胞能