Effects of combined application of Nogo-neutralizing antibody IN-1 and neurotrophin-3 on c-Fos and c-Jun expression in a rat model of hemisection spinal cord injury

BACKGROUND:Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 (NT-3)contributes to regeneration of nerve fibers in the spinal cord and motor function recovery. The combination of Nogo-neutralizing antibody IN-1 and NT-3 is hypothesized to produce better outcomes and facilitate axonal regeneration by affecting c-Fos and c-Jun protein expression. OBJECTIVE:To investigate the combined effects of Nogo-neutralizing antibody IN-1 and NT-3 on c-Fos and c-Jun protein levels in the injured spinal cord. DESIGN,TIME AND SETTING:A randomized,controlled study was performed at the Laboratory of Neuroanatomy,Xiangya Medical College,Central South University and the Central Laboratory of Third Xiangya Hospital of China from June 2005 to December 2007. MATERIALS:NT-3 (Peprotech,USA) and Nogo-neutralizing antibody IN-1 (Santa Cruz Biotechnology,USA) were used in this study. METHODS:Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of rat spinal cord,which is equivalent to the T8 level in the human spine. A total of 120 rats were equally and randomly assigned to three groups:model (0.2 μL saline),IN-1 (0.2 μL IN-1),and IN-1/NT-3 (0.2 μL IN-1 + 0.2 μL NT-3). The compounds were separately infused into transection sites on the side of head. MAIN OUTCOME MEASURES:Western blot analysis was employed to measure c-Fos and c-Jun protein expression in the injured spinal cord at 15,30 minutes,1,2,4,6,8,and 12 hours following surgery. RESULTS:Following spinal cord injury,c-Fos and c-Jun protein expression were increased and peaked at 4-6 hours. Following injection of IN-1 or the combination of IN-1 and NT-3,c-Fos protein expression was significantly reduced in the injured spinal cord (P < 0.05 or P < 0.01) (with the exception of the 15 minute time point). However,c-Jun protein expression was significantly increased (P < 0.05 or P < 0.01) (with the exception of the 15 and 30 minute time points). Combined application of IN-1 and NT-3 resulted in significantly altered protein expression compared to IN-1 alone. CONCLUSION:IN-1 increases c-Jun protein levels and protects the injured spinal cord by inhibiting c-Fos protein levels. Moreover,the effects of IN-1 combined with NT-3 are more significant than with IN-1 alone.

Delayed peripheral treatment with neurotrophin-3 improves sensorimotor recovery after central nervous system injury

Neurotrophin-3 (NT3) is a growth factor found in many body tissues including the heart, intestines, skin, nervous system and in skeletal muscles including muscle spindles (Murase et al., 1994). NT3 is required for the survival, correct connectivity and function of sensory (“proprioceptive”) afferents that innervate muscle spindles;these neurons express receptors for NT3 including tropomyocin receptor kinase C. These proprioceptive afferents are important for normal movement (Boyce and Mendell, 2014) and signals from muscle spindles are important for recovery of limb movement (e.g., after spinal cord lateral hemisection)(Takeoka et al., 2014). The level of NT3 declines in most tissues during postnatal development;its level is low in adult and elderly humans and other mammals (Murase et al., 1994). Elevation of NT3 has been shown to improve outcome in various animal models of neurological disease and injury. For example, many groups have shown that delivery of NT3 directly into the central nervous system promotes recovery after spinal cord injury but this often involved invasive routes or gene therapy (Boyce and Mendell, 2014;Petrosyan et al., 2015;Wang et al., 2018).

Effects of neurotrophin-3 intervention on on bone marrow mesenchymal stem cell osteoblast differentiation as well as cell proliferation and apoptosis

Objective:To study the effects of neurotrophin-3 (NT-3) intervention on bone marrow mesenchymal stem cell osteoblast differentiation as well as cell proliferation and apoptosis. Methods: Bone marrow mesenchymal stem cells were cultured and divided into control group, 25 ng/mL NT-3 group, 50 ng/mL NT-3 group and 100 ng/mL NT-3 group, they were treated with different doses of NT-3 for 24 h, and then osteoblast marker gene, cell proliferation gene and apoptosis gene expression were determined.Results: RUNX2, Osterix, ALP, OCN, BMP-2, Bcl-2, Nrf2, ERK1/2 and PCNA mRNA expression in 25 ng/mL NT-3 group, 50 ng/mL NT-3 group and 100 ng/mL NT-3 group were significantly higher than those in control group whereas Bim, Bax, Caspase-3, CHOP and Beclin1 mRNA expression were significantly lower than those in control group, and the larger the dose of NT-3, the higher the RUNX2, Osterix, ALP, OCN, BMP-2, Bcl-2, Nrf2, ERK1/2 and PCNA mRNA expression whereas the lower the Bim, Bax, Caspase-3, CHOP and Beclin1 mRNA expression.Conclusion: NT-3 intervention in bone marrow mesenchymal stem cells can promote osteoblast differentiation and cell proliferation and inhibit apoptosis.

Survival of transplanted neurotrophin-3 expressing human neural stem cells and motor function in a rat model of spinal cord injury

<正>BACKGROUND:Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation,Schwann cell transplantation,olfactory ensheathing cell transplantation,and embryonic neural tissue transplantation.However,there is a need for improved outcomes. OBJECTIVE:To investigate the repair feasibility for rat spinal cord injury using human neural stem cells(hNSCs) genetically modified by lentivirus to express neurotrophin-3. DESIGN,TIME AND SETTING:In vitro cell biological experiment and in vivo randomized,controlled, genetic engineering experiment were performed at the Third Military Medical University of Chinese PLA and First People's Hospital of Yibin,China from March 2006 to December 2007. MATERIALS:A total of 64 adult,female,Wistar rats were used for the in vivo study.Of them,48 rats were used to establish models of spinal cord hemisection,and were subsequently equally and randomly assigned to model,genetically modified hNSC,and normal hNSC groups.The remaining 16 rats served as normal controls. METHODS:hNSCs were in vitro genetically modified by lentivirus to secrete both green fluorescence protein and neurotrophin-3.Neurotrophin-3 expression was measured by Western blot. Genetically modified hNSC or normal hNSC suspension(5×10~5) was injected into the rat spinal cord following T_(10) spinal cord hemisection.A total of 5μL Dulbecco's-modified Eagle's medium was infused into the rat spinal cord in the model group.Transgene expression and survival of transplanted hNSCs were determined by immunohistochemistry.Motor function was evaluated using the Basso,Beattie,and Bresnahan(BBB) scale. MAIN OUTCOME MEASURES:The following parameters were measured:expression of neurotrophin-3 produced by genetically modified hNSCs,transgene expression and survival of hNSCs in rats,motor function in rats. RESULTS:hNSCs were successfully genetically modified by lentivirus to stably express neurotrophin-3.The transplanted hNSCs primarily gathered at,or around,the injection site two weeks following transplantation,and gradually migrated towards the surrounding tissue. Transplanted hNSCs were observed 7.0-8.0 mm away from the injection site.In addition,hNSCs were observed 10 weeks after transplantation.At week 4,BBB locomotor scores were significantly greater in the genetically modified hNSC and normal hNSC groups,compared with the model group (P<0.05),and scores were significantly greater in the genetically modified hNSC group compared with the normal hNSC group(P<0.05). CONCLUSION:hNSCs were genetically modified with lentivirus to stably secrete neurotrophin-3. hNSCs improved motor function recovery in rats following spinal cord injury.

Transplantation of neurotrophin-3-transfected bone marrow mesenchymal stem cells for the repair of spinal cord injury

Bone marrow mesenchymal stem cell transplantation has been shown to be therapeutic in the repair of spinal cord injury. However, the low survival rate of transplanted bone marrow mesenchymal stem cells in vivo remains a problem. Neurotrophin-3 promotes motor neuron survival and it is hypothesized that its transfection can enhance the therapeutic effect. We show that in vitro transfection of neurotrophin-3 gene increases the number of bone marrow mesenchymal stem cells in the region of spinal cord injury. These results indicate that neurotrophin-3 can promote the survival of bone marrow mesenchymal stem cells transplanted into the region of spinal cord injury and potentially enhance the therapeutic effect in the repair of spinal cord injury.

Effects of Nogo-neutralizing antibody and neurotrophin-3 on axonal regeneration following spinal cord injury in rats

BACKGROUND: Recent studies have suggested that regeneration of the central nerve fiber following spinal cord injury occurs under specific conditions. OBJECTIVE: To study the effects of Nogo-neutralizing antibody (IN-1), in combination with neurotrophin-3 (NT-3), on axonal regeneration and motor function following spinal cord injury in the rat. DESIGN, TIME AND SETTING: A randomized, controlled, animal study combining immunohistochemistry was performed at the Laboratory of Neuroanatomy of Xiangya Medical College, and Central Laboratory of Xiangya the Third Hospital, Central South University from January 2006 to December 2007. MATERIALS: Eighteen healthy, Sprague Dawley rats were randomly divided into three groups, with six rats per group: control, IN-1, and IN-1/NT-3. Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of spinal cord, which is equivalent to the T8 level. METHODS: A polyethylene tubing was inserted through into subarachnoid cavity, equivalent to the superior margin at the T8 level. Saline, IN-1, and IN-1/NT-3 were respectively injected into control, IN-1, and IN-1/NT-3 groups, three times/day for seven consecutive days. MAIN OUTCOME MEASURES: At 2 weeks post-surgery, biotin dextran amine (10%) was injected into the right sensorimotor cortex area. At day 28 post-surgery, spinal cord tissue was prepared for frozen sections. Positive astrocytic expression was observed with glial fibrillary acidic protein (GFAP) immunohistochemical staining whose proliferation level was represented by gray value, i.e. the higher the gray value was, the less the positive cells were, and growth of positive fibers was observed with a biotin dextran amine histological reaction. Motor function was measured according to BBB scores pre-operatively, as well as at days 1, 7, 14, 21, and 28 post-operatively. RESULTS: Three rats died during experimentation. By random supplement, a total of 18 rats were included. GFAP-positive astrocytes were observed in all the three groups. In the control group, astrocytes were characterized according to active function, hyperplasia, proliferation, hypertrophy, and increasing processes as compared to IN-1 group and IN-1/IN-3 group. Astrocyte hyperplasia represented by gray value in the IN-1 group was less than the control group. Gray value of GFAP-positive products in the IN-1/IN-3 group was higher than other two groups (P < 0.05). Biotin dextran amine tracing demonstrated no corticospinal tract fiber outgrowth following spinal cord injury; the fibers were incapable of passing through the glial scar in the control group. Several fibers were distributed in the proximal scar tissue region in the IN-1 group, and the regenerated fibers were disarranged. Many nerve fibers were distributed throughout the scar tissue, and even several biotin dextran amine-positive fibers were observed at the distal end of the injured segment. Post-operative Basso, Beattie, Bresnahan scores were greater than pre-operative ones, while Basso, Beattie, Bresnahan scores in the IN-1/NT-3 group were significantly greater than the other two groups at days 14, 21, and 28 post-surgery (P < 0.05). CONCLUSION: IN-1, in combination with NT-3, promoted axonal regeneration following spinal cord injury, inhibited the colloidal effect, and enhanced the correlation between proximal and distal processes to recover motor function. The recovery effect of IN-1/NT-3 on motor function was superior that of to IN-1 alone.

Nanoparticles carrying neurotrophin-3-modified Schwann cells promote repair of sciatic nerve defects

Schwann cells and neurotrophin-3 play an important role in neural regeneration,but the secretion of neurotrophin-3 from Schwann cells is limited,and exogenous neurotrophin-3 is inactived easily in vivo.In this study,we have transfected neurotrophin-3 into Schwann cells cultured in vitro using nanoparticle liposomes.Results showed that neurotrophin-3 was successfully transfected into Schwann cells,where it was expressed effectively and steadily.A composite of Schwann cells transfected with neurotrophin-3 and poly(lactic-co-glycolic acid) biodegradable conduits was transplanted into rats to repair 10-mm sciatic nerve defects.Transplantation of the composite scaffold could restore the myoelectricity and wave amplitude of the sciatic nerve by electrophysiological examination,promote nerve axonal and myelin regeneration,and delay apoptosis of spinal motor neurons.Experimental findings indicate that neurotrophin-3 transfected Schwann cells combined with bridge grafting can promote neural regeneration and functional recovery after nerve injury.

Effect of neurotrophin-3 on SOD and MDA in rats after acute spinal cord injury

Objective:To investigate the effect of neurotrophin-3 on the expressions of SOD and MDA in the injured spinal cord of rats. Methods: Totally 105 SD rats were randomly divided into 3 groups (n = 35): sham group, control group and experimental group. Animal model of acute spinal cord was inflicted with Allen's method by a thin plastic tube situated in subarachnoid space below the injury level for perfusion. Rats in experimental group received 20μl NT-3 (200 ng) from the tube at 0, 4. 8. 12. 24 h and 3. 7 d after injury, and those in control group got the equal volume of normal saline at the same time points. The animals in sham group only received opening vertebral plate and putting tube in subarachnoid space. The rats were sacrificed at 4, 8. 12. 24 h, and 3. 7, 14 d postinjury (n = 5). And the levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in blood were observed with colorimetric method. Results: The serum level of SOD reduced obviously and the level of MDA raised obviously in rats after the injury, and the activity of SOD reached the lowest on day 3 and the concentration of MDA reached peak at the 7 d. In the experimental group, the SOD level was obviously higher (P<0. 01). and MDA level was lower than the control (P<0. 01). Conclusion:NT-3 can mitigate secondary injury of spinal cord in vivo. One of mechanisms is that inhibits abnormal expression of MDA and elevates the activity of SOD. thus the injury of free radical and lipid peroxidation is attenuated.

Endogenous neurotrophin-3 promotes neuronal sprouting from dorsal root ganglia

In the present study, we investigated the role of endogenous neurotrophin-3 in nerve terminal sprouting 2 months after spinal cord dorsal root rhizotomy. The left L1–5 and L7–S2 dorsal root ganglia in adult cats were exposed and removed, preserving the L6 dorsal root ganglia. Neurotrophin-3 was mainly expressed in large neurons in the dorsal root ganglia and in some neurons in spinal lamina II. Two months after rhizotomy, the number of neurotrophin-3-positive neurons in the spared dorsal root ganglia and the density of neurite sprouts emerging from these ganglia were increased. Intraperitoneal injection of an antibody against neurotrophin-3 decreased the density of neurite sprouts. These findings suggest that endogenous neurotrophin-3 is involved in spinal cord plasticity and regeneration, and that it promotes axonal sprouting from the dorsal root ganglia after spinal cord dorsal root rhizotomy.

Construction of a eukaryotic expression plasmid for human retina-derived neurotrophin-3

Neurotrophin-3 (NT-3) can promote the repair of central nervous system and retinal damage. In previous reports, NT-3 has been expressed by viral vectors. However, plasmid vectors have a safer profile compared with viral vectors in clinical studies. This study recombined amplified human retinal NT-3 with a eukaryotic expression plasmid containing green fluorescent protein (GFP) to construct an NT-3 expression plasmid, pEGFP-N1-NT-3. The transfection efficiency 48 hours after pEGFP-N1-NT-3 transfection to 293T cells was 50.06 ± 2.78%. Abundant NT-3-GFP was expressed in 293T cells as observed by fluorescence microscopy, suggesting the construct pEGFP-N1-NT-3 effectively expressed and secreted NT-3-GFP. Secretory vesicles containing NT-3-GFP were observed in a constant location in cells by laser scan confocal microscopy, indicating the expression and secretion processes of NT-3 in eukaryotic cells were in accordance with the physical synthesis processes of secreted proteins. Western blot assay showed that pro-NT-3-GFP had a molecular weight of 56 kDa, further confirming NT-3-GFP expression. At 48 hours after transfection, the concentration of NT-3 in culture medium was 22.3 ng/mL, suggesting NT-3 produced by pEGFP-N1-NT-3 was efficiently secreted. This study constructed a human retinal-derived NT-3 eukaryotic expression plasmid that efficiently expressed and secreted NT-3.

IN-1 combined with neurotrophin-3 for axonal growth-related gene expression after spinal cord injury

A spinal cord hemisection injury model was established in rats. Treatment with IN-1 and/or neuro-trophin-3 was found to regulate the expression of growth-associated protein 43, nerve growth factor, and basic fibroblast growth factor genes in the injured spinal cord tissues; transcript levels were first increased and then decreased. Expression levels reached a peak at days 7 (growth-associated protein 43) or 14 (nerve growth factor and basic fibroblast growth factor) following spinal cord injury. Combined treatment with neurotrophin-3 and IN-1 achieved the most apparent effect on the ex-pression and recovery of motor function. These findings confirm that combined therapy with neuro-trophin-3 and IN-1 can increase expression of growth factors in the injured spinal cord tissues and promote the axonal regeneration.

Location and expression of neurotrophin-3 and its receptor in the brain of human embryos during early development

BACKGROUND: Cell culture in vitro trials have demonstrated that neurotrophin-3 (NT-3) can enhance the survival of sensory neurons and sympathetic neurons, and can also support embryo-derived motor neurons. This effect is dependent on nerve growth factor on the surface of cells. Understanding the role of NT-3 and its receptor in the early development of human embryonic brains will help to investigate the correlation between early survival of nerve cells and the microenvironment of neural regeneration. OBJECTIVE: To observe the proliferation of cerebral neurons in the development of human embryonic brain, and to investigate the location, expression and distribution of NT-3 and its receptor TrkC during human brain development. DESIGN, TIME AND SETTING: An observation study on cells was performed in the Department of Human Anatomy, Histology and Embryology, Chengdu Medical College in September 2007. MATERIALS: Fifteen specimens of fresh human embryo, aged 6 weeks, were used in this study. METHODS: The proliferation of cerebral neurons was detected using proliferating cell nuclear antigen, and the immunocytochemistry ABC technique was applied to observe the location, expression and distribution of NT-3 and its receptor TrkC in the brain of the human embryo. MAIN OUTCOME MEASURES: Location, expression and distribution of NT-3 and its receptor in the brain of the human embryo. RESULTS: In the early period (aged 6 weeks) of human embryonic development, proliferating cell nuclear antigen-positive reactive substances were mainly observed in the nucleus of the forebrain ventricular zone and subventricular zone, and the intensity was stronger in the subventricular zone than the forebrain ventricle. NT-3 positive reactive substance was mainly distributed in the cytoblastema of the forebrain neuroepithelial layer and nerve cell process, while TrkC was mainly distributed in the cell membrane of the forebrain ventricular zone and subventricular zone. During embryonic development, NT-3 and TrkC showed a positive immune reaction to a greater or lesser extent in ependymal epithelium. CONCLUSION: During early human embryonic development, cerebral nerve cells proliferate in the ventricular zone and subventricular zone, and NT-3 is expressed in the neural axon. The results show that the highly expressed NT-3 could promote the proliferation of neural axons and maintain the neuron body’s survival.

Effects of neurotrophin-3 on the differentiation of neural stem cells into neurons and oligodendrocytes

In this study,cells from the cerebral cortex of fetal rats at pregnant 16 days were harvested and cultured with 20 μg/L neurotrophin-3.After 7 days of culture,immunocytochemical staining showed that,22.4% of cells were positive for nestin,10.5% were positive for β-III tubulin(neuronal marker),and 60.6% were positive for glial fibrillary acidic protein,but no cells were positive for O4(oligodendrocytic marker).At 14 days,there were 5.6% nestin-,9.6% β-III tubulin-,81.1% glial fibrillary acidic protein-,and 2.2% O4-positive cells.In cells not treated with neurotrophin-3,some were nestin-positive,while the majority showed positive staining for glial fibrillary acidic protein.Our experimental findings indicate that neurotrophin-3 is a crucial factor for inducing neural stem cells differentiation into neurons and oligodendrocytes.

Expression and biological activity of double replica retrovirus carrier-mediated neurotrophin-3 in olfactory ensheathing cells

BACKGROUND:Previous studies have demonstrated that the combination of olfactory ensheathing cells(OECs) and neurotrophic factor-3(NT-3) in the rat lateral ventricle can promote nerve axonal regeneration and myelin sheath repair.However,this effect remains very short-lived, OBJECTIVE:To transfect NT-3 into OECs and to observe the biological activity of OEC-expressing NT-3. DESIGN,TIME AND SETTING:This genetic engineering,in vitro experiment was performed in the Provincial Hospital Affiliated to Shandong University between January 2007 and October 2008. MATERIALS:Trizol Reagent kit was purchased from Gibco,USA;reverse transcription kit,NT-3 Emax^(?)ImmunoAssay System reagent was purchased from Promega,USA. METHODS:Neonatal Wistar rat OECs were established as primary cultures and were transfected with pN2A-NT-3 viral vector.The OECs with the highest virus titer and stable cellular growth served as the transfection group;OECs transfected with NT-3-free retrovirus carrier pN2A served as the empty vector group;un-transfected OECs served as the control group.After adherence,the logarithmically cultured PC12-TrkC cells were plated in OECs supernatant from the transfection and empty vector groups,as well as 20μL PBS,and cultured for 4 days. MAIN OUTCOME MEASURES:NT-3 mRNA expression in OECs,fluorescence of NT-3-positive cells in the transfection group and control group;influence of OECs secreting NT-3 on the differentiation ratio of PC12-TrkC cells. RESULTS:NT-3 mRNA expression was observed 24 hours after transfection and lasted for 28 days, which was greater than the control and empty vector groups(P<0.01).A large number of NT-3-positive cells were observed in the transfection group,and immunofluorescence was greater than the control and empty vector groups.PC12-TrkC cells co-cultured with OECs from the transfection group exhibited a thick and long cell process,increased cell density,and the differentiation ratio was increased(P<0.01). CONCLUSION:Recombinant double replica retrovirus NT-3 gene was stably and effectively expressed in OECs,and the expressed NT-3 possessed biological activity that promoted neuronal survival.

Influence of neurotrophin-3 on Bcl-2 and Bax expressions in spinal cord injury of rats

Objective:To study the protective mechanisms of neurotrophin-3 (NT-3) on the spinal cord injury. Methods: Totally 105 SD rats were randomly divided into 3 groups: control group, experimental group and sham operation group. Rats from the former 2 groups were inflicted to animal model of acute spinal cord injury according to Allen's (WD) by situating a thin plastic tube in the subarachnoid space below the injury level for perfusion. Rats in experimental group received 20μl NT-3 (200 ng) from the tube at 0, 4, 8, 12, 24 h and 3, 7 d after injury, and those in control group got an equal volume of normal saline at the same time. The animals in sham operation group only received opening vertebral plate and tube was put in subarachnoid space. The rats were sacrificed at 4, 8, 12, 24 h and 3, 7, 14 d post injury (n = 5). The expression levels of Bcl-2 and Bax proteins in spinal cord of rats were detected by immunohis-tochemistry assay. Results: The level of Bax protein in control group significantly increased as compared with those in sham operation group, and the peak reached at 8 h after spinal cord injury. The Bcl-2 proteins were always weakly positive. The Bax proteins in NT-3 group significantly decreased but the Bcl-2 proteins obviously increased as compared with those in control group. Conclusion: NT-3 can protect spinal cord from injury in vivo. One of the mechanisms is that NT-3 can inhibit abnormal expression of Bax protein, and increase the expression of Bcl-2 protein, then inhibit apoptosis after spinal cord injury.

THE CLONING OF HUMAN NEUROTROPHIN-3 GENE

Ｎｅｕｒｏｔｒｏｐｈｉｎ－３（ＮＴ－３）ｉｓａｍｅｍｂｅｒｏｆｔｈｅｎｅｕｒｏｔｒｏｐｈｉｎｆａｍｉｌｙｏｆｓｔｒｕｃｔｕｒａｌｙｒｅｌａｔｅｄｐｒｏｔｅｉｎｓ〔１〕．Ｔｈｅｇｅｎｅｏｆｈｕｍａｎｎｅｕｒｏｔｒｏｐｈｉｎ－３（ｈＮＴ－３）ｉｓｌｏｃａ...

有氧运动训练影响阿尔茨海默症小鼠海马Notch1、Caspase-3的表达

背景:β-淀粉样蛋白和Tau蛋白会对阿尔茨海默症患者的认知功能产生不良影响,研究发现Notch1及Caspase-3能够调控β-淀粉样蛋白和Tau蛋白的表达。Notch1及Caspase-3是否介导了有氧运动改善阿尔茨海默症患者认知能力的过程还不清楚,目前缺乏长期有氧运动影响阿尔茨海默症小鼠海马中Notch1及Caspase-3表达的研究。目的:观察长期有氧运动干预阿尔茨海默症小鼠的空间学习记忆情况及其海马中Notch1及Caspase-3的表达,探讨Notch1及Caspase-3对阿尔茨海默症小鼠的影响。方法:将3月龄野生型及APP/PS1双转基因阿尔茨海默症小鼠随机分为4组:野生对照组、野生运动组、阿尔茨海默症对照组、阿尔茨海默症运动组,每组20只。对照组小鼠不进行运动,运动组小鼠进行5个月的有氧运动干预。运动干预结束后,采用Morris水迷宫检测小鼠空间学习记忆能力;采用Real-timePCR、免疫荧光及Westernblot检测各组小鼠海马组织Aβ_(1-42)、Tau、Notch1及Caspase-3蛋白的表达。结果与结论:①阿尔茨海默症小鼠空间学习记忆能力显著差于野生组(P<0.05);运动组小鼠空间学习记忆能力显著优于对照组(P<0.05);②阿尔茨海默症对照组小鼠海马Aβ_(1-42)、Tau、Notch1及Caspase-3表达均显著高于野生对照组(P<0.05);阿尔茨海默症运动组小鼠海马Aβ_(1-42)、Tau、Notch1及Caspase-3表达显著低于阿尔茨海默症对照组(P<0.05);③提示:长期有氧运动干预能够改善阿尔茨海默症小鼠的空间学习记忆能力,而这可能与有氧运动降低阿尔茨海默症小鼠海马Notch1、Caspase-3、Aβ_(1-42)及Tau蛋白表达有关。

STAT3在阿尔茨海默病小鼠认知障碍发生发展中的作用及机制研究

目的 研究信号传导及转录激活因子3(STAT3)在阿尔茨海默病小鼠认知障碍发生发展中的作用及机制。方法 利用C57BL/6J小鼠双侧海马脑立体定位注射β-淀粉样蛋白建立阿尔茨海默病模型,给予STAT3抑制剂氯硝柳胺,运用动物行为学分析检测、Western blot分析检测等探究STAT3在认知障碍中的作用及机制。结果 行为学实验表明,与模型组小鼠相比,给药组小鼠的焦虑症状、空间探索能力、物体识别能力和学习记忆能力均得到改善;Western blot分析结果表明,给药后小鼠阿尔茨海默病的病理标志物改善,促炎因子表达下调;试剂盒分析结果显示给药组小鼠氧化应激相关指标改善;HE染色结果显示给药组小鼠海马神经元组织形态的改善。结论 本研究初步证明了抑制STAT3可减轻神经炎症和氧化应激,从而改善阿尔茨海默病小鼠的认知障碍。

沈阳市O_(3)与PM_(2.5)关系及污染主控因素分析

PM_(2.5)与O_(3)的协同控制是空气质量持续改善的关键所在,厘清PM_(2.5)与O_(3)的关系,识别O_(3)主控因素以及量化气象和人为排放贡献是实施二者协同控制的基础.本研究基于沈阳市大气复合立体超级站2019−2022年地面观测数据,分析PM_(2.5)和O_(3)协同关系及成因;利用逐步回归模型得到影响O_(3)变化的主控因素,并估算各气象因素对O_(3)的贡献.结果表明:①沈阳市2019−2022年夏季PM_(2.5)浓度与O_(3)浓度呈正相关,有明显的协同增长效应,其余三季均呈明显负相关.究其原因,主要是由于夏季高温和高太阳辐射条件利于大气光化学反应,促进了O_(3)、PM_(2.5)中二次无机成分〔主要是硫酸盐(SO_(4)^(2−))、硝酸盐(NO_(3)−)和铵盐(NH_(4)^(+)),简称“SNA”〕共同增长所致;而冬季高排放和高大气稳定度等气象条件利于SNA和二次有机碳(SOC)非均相生成,但弱太阳辐射和低温等条件不利于O_(3)光化学生成,加之高NO的滴定效应,使SNA和SOC浓度均与O_(3)浓度呈负相关.②在观测的相关污染物和气象因子中,过氧乙酰硝酸酯(PAN)与O_(3)浓度的关系最为密切,尤其在夏季.③气象因素中,O_(3)浓度与气温高度相关,与风速也呈正相关,而与相对湿度则在各季节均呈负相关.冬、春、秋三季PM_(2.5)均对O_(3)起抑制作用,冬季尤为突出.在高浓度O_(3)污染(O_(3)浓度>160μg/m^(3))过程中,主控因素中气温和风速的抬升促进O_(3)浓度升高,而高NO2和相对湿度(RH)则有利于降低O_(3)浓度.在2019−2022年高浓度O_(3)污染过程中,气象因素对沈阳市O_(3)浓度变化的贡献高于O_(3)前体物排放的贡献,总贡献为57μg/m^(3),对污染形成起着主导作用.

复合添加MgO和La_(2)O_(3)对纳米微晶氧化铝陶瓷微观结构的影响

纳米微晶氧化铝磨料具有良好的通用性和高精度磨削能力,且性价比较高,在机械制造、轴承、模具、汽车等领域有广泛的应用潜力。本研究以勃姆石(γ-AlOOH)为原料,MgO、La_(2)O_(3)为添加剂,采用溶胶-凝胶工艺合成纳米微晶氧化铝。通过差示扫描量热仪、X射线衍射仪、扫描电子显微镜和从头算分子动力学方法模拟计算研究了添加剂对微晶氧化铝相转化、物相组成、微观结构及力学性能的影响。结果表明:复合添加MgO和La2O3可以使氧化铝中间相θ-Al_(2)O_(3)向α-Al_(2)O_(3)转化的温度从1257℃降低到1105℃,将致密化温度从1600℃降低到1350℃,将微晶氧化铝的晶粒尺寸从1.04 mm减小到120 nm,实现了低温致密烧结。