TRPV4-induced Neurofilament Injury Contributes to Memory Impairment after High Intensity and Low Frequency Noise Exposures

Objective Exposure to high intensity, low frequency noise(HI-LFN) causes vibroacoustic disease(VAD),with memory deficit as a primary non-auditory symptomatic effect of VAD. However, the underlying mechanism of the memory deficit is unknown. This study aimed to characterize potential mechanisms involving morphological changes of neurons and nerve fibers in the hippocampus, after exposure to HILFN.Methods Adult wild-type and transient receptor potential vanilloid subtype 4 knockout(TRPV4^(-/-)) mice were used for construction of the HI-LFN injury model. The new object recognition task and the Morris water maze test were used to measure the memory of these animals. Hemoxylin and eosin and immunofluorescence staining were used to examine morphological changes of the hippocampus after exposure to HI-LFN.Results The expression of TRPV4 was significantly upregulated in the hippocampus after HI-LFN exposure. Furthermore, memory deficits correlated with lower densities of neurons and neurofilamentpositive nerve fibers in the cornu ammonis 1(CA1) and dentate gyrus(DG) hippocampal areas in wildtype mice. However, TRPV4^(-/-)mice showed better performance in memory tests and more integrated neurofilament-positive nerve fibers in the CA1 and DG areas after HI-LFN exposure.Conclusion TRPV4 up-regulation induced neurofilament positive nerve fiber injury in the hippocampus,which was a possible mechanism for memory impairment and cognitive decline resulting from HI-LFN exposure. Together, these results identified a promising therapeutic target for treating cognitive dysfunction in VAD patients.

Current application of neurofilaments in amyotrophic lateral sclerosis and future perspectives

Motor neuron disease includes a heterogeneous group of relentless progressive neurological disorders defined and characterized by the degeneration of motor neurons.Amyotrophic lateral sclerosis is the most common and aggressive form of motor neuron disease with no effective treatment so far.Unfortunately,diagnostic and prognostic biomarkers are lacking in clinical practice.Neurofilaments are fundamental structural components of the axons and neurofilament light chain and phosphorylated neurofilament heavy chain can be measured in both cerebrospinal fluid and serum.Neurofilament light chain and phosphorylated neurofilament heavy chain levels are elevated in amyotrophic lateral sclerosis,reflecting the extensive damage of motor neurons and axons.Hence,neurofilaments are now increasingly recognized as the most promising candidate biomarker in amyotrophic lateral sclerosis.The potential usefulness of neurofilaments regards various aspects,including diagnosis,prognosis,patient stratification in clinical trials and evaluation of treatment response.In this review paper,we review the body of literature about neurofilaments measurement in amyotrophic lateral sclerosis.We also discuss the open issues concerning the use of neurofilaments clinical practice,as no overall guideline exists to date;finally,we address the most recent evidence and future perspectives.

Neurofilament proteins in axonal regeneration and neurodegenerative diseases

Neurofilament protein is a component of the mature neuronal cytoskeleton, and it interacts with the zygosome, which is mediated by neurofilament-related proteins. Neurofilament protein regulates enzyme function and the structure of linker proteins. In addition, neurofilament gene expression plays an important role in nervous system development. Previous studies have shown that neurofilament gene transcriptional regulation is crucial for neurofilament protein expression, especially in axonal regeneration and degenerative diseases. Post-transcriptional regulation increased neurofilament protein gene transcription during axonal regeneration, ultimately resulting in a pattern of neurofilament protein expression. An expression imbalance of post-transcriptional regulatory proteins and other disorders could lead to amyotrophic lateral sclerosis or other neurodegenerative diseases. These findings indicated that after transcription, neurofilament protein regulated expression of related proteins and promoted regeneration of damaged axons, suggesting that regulation disorders could lead to neurodegenerative diseases.

Calcium-dependent proteasome activation is required for axonal neurofilament degradation

Even though many studies have identified roles of proteasomes in axonal degeneration, the mo- lecular mechanisms by which axonal injury regulates proteasome activity are still unclear. In the present study, we found evidence indicating that extracellular calcium influx is an upstream regulator of proteasome activity during axonal degeneration in injured peripheral nerves. In degenerating axons, the increase in proteasome activity and the degradation of ubiquitinated proteins were sig- nificantly suppressed by extracellular calcium chelation. In addition, electron microscopic findings revealed selective inhibition of neurofilament degradation, but not microtubule depolymerization or mitochondrial swelling, by the inhibition of calpain and proteasomes. Taken together, our findings suggest that calcium increase and subsequent proteasome activation are an essential initiator of neurofilament degradation in Wallerian degeneration.

Neuronal apoptosis and neurofilament protein expression in the lateral geniculate body of cats following acute optic nerve injuries

The visual pathway have 6 parts, involving optic nerve, optic chiasm, optic tract, lateral geniculate body, optic radiation and cortical striatum area. Corresponding changes may be found in these 6 parts following optic nerve injury. At present, studies mainly focus on optic nerve and retina, but studies on lateral geniculate body are few. OBJECTIVE： To prepare models of acute optic nerve injury for observing the changes of neurons in lateral geniculate body, expression of neurofilament protein at different time after injury and cell apoptosis under the optical microscope, and for investigating the changes of neurons in lateral geniculate body following acute optic nerve injury. DESIGN： Completely randomized grouping design, controlled animal experiment. SETTING： Department of Neurosurgery, General Hospital of Ji＇nan Military Area Command of Chinese PLA. MATERIALS： Twenty-eight adult healthy cats of either gender and common grade, weighing from 2.0 to 3.5 kg, were provided by the Animal Experimental Center of Fudan University. The involved cats were divided into 2 groups according to table of random digit： normal control group （n=3） and model group （n=25）. Injury 6 hours, l, 3, 7 and 14 days five time points were set in model group for later observation, 5 cats at each time point. TUNEL kit （Bohringer-Mannheim company ）and NF200＆ Mr 68 000 mouse monoclonal antibody （NeoMarkers Company） were used in this experiment. METHODS： This experiment was carded out in the Department of Neurosurgery, General Hospital of Ji＇nan Military Area Command of Chinese PLA between June 2004 and June 2005.① The cats of model group were developed into cat models of acute intracranial optic nerve injury as follows： The anesthetized cats were placed in lateral position. By imitating operation to human, pterion approach was used. An incision was made at the joint line between outer canthus and tragus, and deepened along cranial base until white optic nerve via optic nerve pore and further to brain tissue. Optic nerve about 3 mm was liberated and occluded by noninvasive vascular clamp for 20 s. After removal of noninvasive vascular clamp, the area compressed by optic nerve was hollowed and narrowed, but non-fractured. Skull was closed when haemorrhage was not found. Bilateral pupillary size, direct and indirect light reflect were observed. Operative side pupil was enlarged as compared with opposite side, direct light reflect disappeared and indirect light reflect existed, which indicated that the models were successful. Animals of control group were not modeled .② The animals in the control group and model group were sacrificed before and 6 hours, 1, 3, 7 and 14 days after modeling respectively. Lateral geniculate body sample was taken and performed haematoxylin ＆ eosin staining. Immunohistochemical staining showed lateral geniculate body neurofilament protein expression, and a comparison of immunohistochemial staining results was made between experimental group and control group. Terminal deoxynucleo-tidyl transferase （TdT）-mediated dUTP-biotin nick end labeling （TUNEL） was used to label apoptotic cells in lateral geniculate body. MAIN OUTCOME MEASURES： Neuronal morphological change, neurofilament protein expression and cell apoptosis in lateral geniculate body following acute optic nerve injury. RESULTS： Twenty-eight involved cats entered the final analysis. ① Histological observation results： In the control group, cell processes were obviously found, which were few or shortening in the model group. ② Neuronal neurofilament protein expression： Cells in lateral geniculate body in the control group and at 6 hours after injury presented clear strip-shaped staining, and those at 7 and 14 days presented irregular distribution without layers and obviously decreasing staining intensity. The positive rate of neurofilament protein in lateral geniculate body in control group and 6 hours, l, 3, 7 and 14 days after injury was （ 10.22±0.42） %, （10.03±0.24） %, （9.94±0.14） %, （9.98±0.22） %, （8.18±0.34） % and （6.37±0.18）%, respectively. Positive rate of neurofilament protein in control group, at 6 hours, 1 or 3 days after injury was significantly different from that at 7 days after injury （P 〈 0.05）; Positive rate of neurofilament protein in control group, at 6 hours, 1, 3 or 7 days after injury was significantly different from that at 14 days after injury （P 〈 0.05）. It indicated that neuronal injury in lateral geniculate body was not obvious within short term after optic nerve injury, but obvious at 7 days after injury and progressively aggravated until at 14 days after injury.③ Neuronal apoptosis： TUNEL staining showed that neuronal apoptosis in lateral geniculate body appeared at 7 days after injury, and a Lot of neuronal apoptosis in lateral geniculate body was found at 14 days after injury. It indicated that neuronal injury in lateral geniculate body was related to apoptosis. CONCLUSION： In short term after optic nerve injury （within 7 days）, nerve injury of lateral geniculate body is not obvious, then, it will aggravate with the elongation of injury time. The occurrence of neuronal iniury of lateral geniculate body is related to the apoptosis of nerve cells.

Growth associated protein 43 and neurofilament immunolabeling in the transected lumbar spinal cord of lizard indicates limited axonal regeneration

Previous cytological studies on the transected lumbar spinal cord of lizards have shown the presence of differentiating glial cells,few neurons and axons in the bridge region between the proximal and distal stumps of the spinal cord in some cases.A limited number of axons(20-50)can cross the bridge and re-connect the caudal stump of the spinal cord with small neurons located in the rostral stump of the spinal cord.This axonal regeneration appears to be related to the recovery of hind-limb movements after initial paralysis.The present study extends previous studies and shows that after transection of the lumbar spinal cord in lizards,a glial-connective tissue bridge that reconnects the rostral and caudal stumps of the interrupted spinal cord is formed at 11-34 days post-injury.Following an initial paralysis some recovery of hindlimb movements occurs within 1-3 months post-injury.Immunohistochemical and ultrastructural analysis for a growth associated protein 43(GAP-43)of 48-50 k Da shows that sparse GAP-43 positive axons are present in the proximal stump of the spinal cord but their number decreased in the bridge at 11-34 days post-transection.Few immunolabeled axons with a neurofilament protein of 200-220 k Da were seen in the bridge at 11-22 days post-transection but their number increased at 34 days and 3 months post-amputation in lizards that have recovered some hindlimb movements.Numerous neurons in the rostral and caudal stumps of the spinal cord were also labeled for GAP43,a cytoplasmic protein that is trans-located into their axonal growth cones.This indicates that GAP-43 biosynthesis is related to axonal regeneration and sprouting from neurons that were damaged by the transection.Taken together,previous studies that utilized tract-tracing technique to label the present observations confirm that a limited axonal re-connection of the transected spinal cord occurs 1-3 months post-injury in lizards.The few regenerating-sprouting axons within the bridge reconnect the caudal with the rostral stumps of the spinal cord,and likely contribute to activate the neural circuits that sustain the limited but important recovery of hind-limb movements after initial paralysis.The surgical procedures utilized in the study followed the regulations on animal care and experimental procedures under the Italian Guidelines(art.5,DL 116/92).

Oxidative phosphorylated neurofilament protein M protects spinal cord against ischemia/reperfusion injury

Previous studies have shown that neurofilament protein M expression is upregulated in the early stage of spinal cord ischemia/reperfusion injury, indicating that this protein may play a role in the injury process. In the present study, we compared protein expression in spinal cord tissue of rabbits after 25 minutes of ischemia followed by 0, 12, 24, or 48 hours of reperfusion with that of sham operated rabbits, using proteomic two-dimensional gel electrophoresis and mass spec- trometry. In addition, the nerve repair-related neurofilament protein M with the unregulated expression was detected with immunohistochemistry and western blot analysis. Two-dimen- sional gel electrophoresis and mass spectrometry showed that, compared with the sham group, upregulation of protein expression was most significant in the spinal cords of rabbits that had undergone ischemia and 24 hours of reperfusion. Immunohistochemical analysis revealed that neurofilament protein M was located in the membrane and cytoplasm of neuronal soma and axons at each time point after injury. Western blot analysis showed that neurofilament protein M expression increased with reperfusion time until it peaked at 24 hours and returned to baseline level after 48 hours. Furthermore, neurofilament protein M is phosphorylated under oxidative stress, and expression changes were parallel for the phosphorylated and non-phosphorylated forms. Neurofilament protein M plays an important role in spinal cord ischemia/reperfusion injury, and its functions are achieved through oxidative phosphorylation.

Neurofilament 200 expression in a rat model of complete spinal cord injury following growth-associated protein-43 treatment

BACKGROUND： Growth-associated protein-43 （GAP-43） expression in the nervous system has been demonstrated to promote neural regeneration, neuronal growth and development, as well as synaptic reconstruction. Neurofilament 200 （NF200） expression could reflect degree of injury and repair in injured spinal axons. OBJECTIVE： To observe NF200 expression changes in a rat model of complete spinal cord injury following GAP-43 treatment and to explore the effects of GAP-43 following spinal cord injury. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Histology and Embryology of Kunming Medical University between March 2007 and October 2008. MATERIALS： GAP-43 and GAP-43 antibody were provided by Beijing Boao Biology, China; mouse anti-rat NF200 antibody was purchased from Chemicon, USA. METHODS： Female, 8-week-old, Sprague Dawley rats were randomly assigned into three groups following complete spinal cord injury, with 20 animals in each group： GAP-43 antibody, GAP-43, and model groups. In addition, each group was subdivided into four subgroups according to sampling time after modeling, Le., 3-, 5-, 9-, and 15-day groups, with 5 rats in each group. GAP-43 antibody or GAP-43 was injected into injury sites of the spinal cord, 5 μg/0.2 mL, respectively, twice daily for three consecutive days, followed by three additional days of injection, once daily. The model group did not receive any treatment following injury. MAIN OUTCOME MEASURES： NF200 expression in the damaged spinal area at different stages was detected by immunohistochemistry; lower limb motion function following injury was evaluated using the Basso, Beattie and Bresnahan （BBB） locomotor rating scale. RESULTS： NF200 expression was significantly reduced in the GAP-43 antibody group, compared with GAP-43 and model groups, at 3 and 5 days after spinal cord injury （P 〈 0.05）. In addition, the model group expressed significantly less NF200 than the GAP-43 group （P 〈 0.05）. BBB scores from the GAP-43 antibody and model groups were remarkably less than the GAP-43 group （P 〈 0.05）. At 9 and 15 days of injury after drug withdrawal, NF200 expression was increased in the GAP-43 antibody group, and NF200 expression and BBB scores in the GAP-43 antibody and GAP-43 groups were significantly greater than in the model group （P 〈 0.05）. In particular, the GAP-43 group exhibited greater BBB scores than the GAP-43 antibody group at day 9 （P 〈 0.05）. CONCLUSION： GAP-43 promoted NF200 expression and recovery of lower limb function. Early administration of GAP-43 antibody produced reversible nerve inhibition, which was rapidly restored following withdrawal.

Effect of GSK-3 Overactivation on Neurofilament Phosphorylation

In this study, we studied the effect of glycogen synthase kinase-3 （GSK-3） overactivation on neurofilament phosphorylation in cultured cells. After N2a cells were treated with the specific inhibitor （wortmannin） of phosphomosnol-3 kinase （PI-3K） or treated with wortmannin and the specific inhibitor （LiCl） of glycogen synthase kinase-3 （GSK-3）, GSK-3 activity and neurofilament phosphorylation were detected by using GSK-3 activity assay, Western blots and immunofluoresence. Our results showed that after treatment of N2a cells with wortmannin for 1 h, overactivation of GSK-3 caused a reduced staining with antibody SMI32 and an enhanced staining with antibody SMI31. When N2a cells were treated with wortmannin and LiCl, the activity of GSK-3 was reduced substantially. At the same time, the phosphorylation of neurofilament was also reduced. The study demonstrated that overactivation of GSK-3 induced hyperphosphorylation of neurofilament and suggested that in vitro overactivation of GSK-3 resulted in neurofilament hyperphosphorylation and this may be the underlying mechanism for Alzheimer＇s disease.

Plasma neurofilament light as a longitudinal biomarker of neurodegeneration in Alzheimer’s disease

Objective:To examine whether plasma neurofilament light(NFL)might be a potential longitudinal biomarker for Alzheimer’s disease(AD).Methods:A total of 835 individuals from the Alzheimer’s Disease Neuroimaging Initiative were involved.Correlations of the rate of change in plasma NFL with cerebrospinal fluid biomarkers,cognition,and brain structure were investigated.Cox proportional hazards models were used to assess the associations between quartiles of plasma NFL and the risk of AD conversion.Results:Participants were further divided intoβamyloid-positive(Aβ+)versusβamyloid-negative(Aβ-),resulting in five biomarker group combinations,which are CN Aβ-,CN Aβ+,MCI Aβ-,MCI Aβ+and AD Aβ+.Plasma NFL concentration markedly increased in the five groups longitudinally(p<0.001)with the greatest rate of change in AD Aβ+group.The rate of change in plasma NFL was associated with cognitive deficits and neuroimaging hallmarks of AD over time(p<0.005).Compared with the bottom quartile,the top quartile of change rate was associated with a 5.41-fold increased risk of AD(95%CI=1.83-16.01)in the multivariate model.Conclusion:Our finding implies the potential of plasma NFL as a longitudinal noninvasive biomarker in AD.

Expression of neurofilament gene in spinal motoneurons during neural regeneration

The technique in situ hybridization was used to measure the levels of light （NF-L）,medium（NF-M） and heavy （NF-H） neurofilament protein subunits mRNA in L4-6 spinal motoneurons in adult rat during regeneration following a unilateral crush of the sciatic nerve.It was found that the hybridization signals of each neurofilament subunit mRNA were dramatically decreased in spinal motoneurons postaxotomy by light microscopy. The hybridization signals of NF-L and NF-M mRNA were located in cytoplasm of neurons, whereas NF-H mRNA was found in both nucleus and cytoplasm of neurons. lmage analysis showed that the encoding levels of mRNA for each of neurofilament subunit mRNA reduced on the 3rd d and returned to control levels on the 28th d following the lesion. The relative levels of mRNA coding for each neurofilament subunit were significantly different. The lowest level of NF-L mRNA was observed at 5 d postaxotomy, and that of NF-M, NF-H mRNA on the 7th and 10th d after injury. Moreover,the levels of HF-M and

Neurofilament light protein and risk of mild cognitive impairment

BACKGROUND AND OBJECTIVE Prognostic markers for Alzheimer′s disease have included cerebral spinal fluid amyloid-beta 42 (Aβ-42), total tau (T-Tau) and phosphorus related tau (P-Tau). Two more recently identified biomarkers are neurofilament light protein (NFL) and neurogranin (NG). NFL is thought to be a marker for subcortical largecaliber axonal degeneration, while NG is believed to be a biomarker for synaptic dysfunction and/or loss. This study investigated whether cerebral spinal fluid levels of NFL and NG are biomarkers of mild cognitive impairment (MCI). METHODS Subjects were a subset of participants in the Mayo Clinic Study of Aging. Data were obtained from 648 individuals without cognitive impairment, all with at least one year of follow-up with cognitive testing. Cerebral spinal fluid was taken by lumbar puncture, with AB42, T-tau, Ptau, NFL and NG measured. The CSF results were compared with the development of MCI at follow-up. RESULTS Data were obtained for 648 patients with an average age of 72.3 years. At a median follow-up of 3.8 years, 14.8% progressed to MCI. Those who progressed to MCI were more frequently carriers of an APOE epsilon allele (P=0.02). Compared with the lowest quartile of CSF NFL, the highest quartile was associated with a 2.9-fold increased risk of MCI. There was no significant association between increased CSF T-Tau, PTau or NG and the risk of MCI. CONCLUSION This prospective study of community dwelling, elderly individuals without cognitive impairment found that elevated levels of neurofilament light protein in the cerebrospinal fluid are associated with an increased risk of developing mild cognitive impairment.

Assembly and structure of neurofilaments isolated from bovine spinal cord

Neurofilaments (NFs) are neuron-specific intermediate filaments. The NFs were isolated from bovine spinal cord by differential centrifugation. The NFs were detected with electron microscopy and scanning tunneling microscopy (STM). Under STM, two kinds of sidearm of NFs were revealed: one was short, the other was long. They were arrayed along the 10-nm width core filaments one by one. The intervals between two adjacent long sidearms or two short sidearms were 20—22 nm, while those between two adjacent long and short sidearms were 10—11 nm. It was proposed that the rod domain of NF triplet prnteins was 3/4-staggered. The assembly properties of NF triplet proteins were also studied. Immuno-colloidal-gold labeling assay showed that NF-M and NF-H are able to co-assemble into long filaments with NF-L. NF-M and NF-H can also co-constitute into winding filaments.

Plasma glial fibrillary acidic protein and neurofilament light chain for the diagnostic and prognostic evaluation of frontotemporal dementia

Background:Astrocytes play an essential role in neuroinflammation and are involved in the pathogenesis of neurodenegerative diseases.Studies of glial fibrillary acidic protein(GFAP),an astrocytic damage marker,may help advance our understanding of different neurodegenerative diseases.In this study,we investigated the diagnostic performance of plasma GFAP(pGFAP),plasma neurofilament light chain(pNfL)and their combination for frontotemporal dementia(FTD)and Alzheimer's disease(AD)and their clinical utility in predicting disease progression.Methods:pGFAP and pNfL concentrations were measured in 72 FTD,56 AD and 83 cognitively normal(CN)participants using the Single Molecule Array technology.Of the 211 participants,199 underwent cerebrospinal(CSF)analysis and 122 had magnetic resonance imaging.We compared cross-sectional biomarker levels between groups,studied their diagnostic performance and assessed correlation between CSF biomarkers,cognitive performance and cortical thickness.The prognostic performance was investigated,analyzing cognitive decline through group comparisons by tertile.Results:Unlike pNfL,which was increased similarly in both clinical groups,pGFAP was increased in FTD but lower than in AD(all P<0.01).Combination of both plasma markers improved the diagnostic performance to discriminate FTD from AD(area under the curve[AUC]:combination 0.78;pGFAP 0.7;pNfL 0.61,all P<0.05).In FTD,pGFAP correlated with cognition,CSF and plasma NfL,and cortical thickness(all P<0.05).The higher tertile of pGFAP was associated with greater change in MMSE score and poor cognitive outcome during follow-up both in FTD(1.40 points annually,hazard ratio[HR]3.82,P<0.005)and in AD(1.20 points annually,HR 2.26,P<0.005).Conclusions:pGFAP and pNfL levels differ in FTD and AD;and their combination is useful for distinguishing between the two diseases.pGFAP could also be used to track disease severity and predict greater cognitive decline during follow-up in patients with FTD.

Neurofilament light chain in demyelinating conditions of the central nervous system: a promising biomarker

Neurofilaments are the major structural proteins of the neuronal cytoskeleton and are classified according to molecular weight into heavy,intermediate,and light chains.They are released into the interstitial fluid and cerebrospinal fluid(CSF)as a consequence of axonal damage.In particular,the light chain(NfL)represents the most abundant and soluble subunit and has been demonstrated to be increased in the CSF of patients with inflammatory,degenerative,vascular,or traumatic injuries in correlation with clinical and radiological activity.Similar results have been obtained measuring serum NfL with high-sensitivity single-molecule array,which enables reliable and repeatable measurement of the low NfL concentrations in serum.In particular,CSF and serum NfL values are strongly correlated in patients with multiple sclerosis(MS)and have been demonstrated to be increased in patients with MS and clinically isolated syndromes(CIS)in accordance with clinical and radiological activity.NfL levels increase in patients with a recent relapse and seem to predict cognitive impairment,long-term outcome,and conversion of CIS to MS.The few available data on patients with other demyelinating diseases suggest that NfL levels are also increased in neuromyelitis optica spectrum disorders and related conditions in correlation with attack severity,suggesting that axonal damage may occur in these disorders.We herein report and discuss published data on the role of NfL as a possible predictor of disease activity,clinical outcome and treatment response in patients with demyelinating conditions of the central nervous system.

Structure of neurofilaments studied with scanning tunneling microscopy

Neurofilaments (NFs) were isolated from bovine spinal cord. The structure of purified NFs was studied by scanning tunneling microscopy (STM). The STM images showed that NF was composed of a long core filament and numerous sidearms flanking the rod regularly. The diameter of the rod was about 10 nm (10.2±0.8 nm). Most of the sidearms were short and the distance between two adjacent sidearms was approximately 10 nm. There were some long sidearms between two proximal core filaments. The distance between two adjacent long sidearms was 21 nm. A three-quarter-staggered fashion of native NF structure was put forward.

Ⅱ型糖尿病兔大脑皮质和海马神经元的神经丝蛋白表达(英文)

Objective:To investigate the morphological changes of the neuronal neurites in diabetic rabbit brain. Methods: Twenty- four New Zealand White rabbits were divided into 2 groups: control group and type Ⅱ diabetic group induced by high - carbohydrate and high- fat diet. The levels of blood sugar and insulin were detected at week 0(w0), w4, w8, w13, w18, w23 and w28. Brain tissue was stained by Nissl staining and immunolistochemistry with a specific antibody to neurofilament proteins. Result: In diabetic rabbits, the amount of large pyramidal neuron was significantly reduced, and neuronal neurites became swollen, whorled, disrupted and changed in caliber. In hippocampus CA1 region neurofilament staining was very weak. Conclusion: Neurotoxicity of chronic hyperglycemia might be relevant to vascular chronic complications, which affected the expression of NF and led to neurophysiological and structural changes in the brain of rabbits with type Ⅱ diabetes.

益气通脉胶囊对脑缺血大鼠学习记忆能力的影响

目的观察益气通脉胶囊对脑缺血损伤后大鼠学习记忆能力的影响及相关机理研究。方法选择SD大鼠90只,按随机数字表法选择10只作为对照组,其余大鼠采用反复夹闭双侧颈总动脉结合硝普钠降压法复制SD大鼠拟血管性痴呆模型。造模后选存活大鼠50只随机分为模型组、脑心通组和益气通脉胶囊高、中、低剂量组,每组各10只,连续给药15 d后通过Morris水迷宫测试大鼠的学习记忆能力,之后取大鼠脑的海马组织,提取蛋白测定生长相关蛋白43(growth associated protein 43,GAP43)和神经丝蛋白-200(Neurofilaments Protein-200,NF200)的表达,以及测定大鼠海马组织NOS活性和NO含量。结果 (1)大鼠的学习记忆能力:益气通脉胶囊高、中剂量组大鼠的学习记忆能力均高于模型组。(2)GAP43和NF200的表达:益气通脉胶囊高、中、低剂量组的蛋白表达均明显大于模型组。(3)益气通脉胶囊高、中剂量组大鼠的NOS活性和NO含量均显著低于模型组。结论益气通脉胶囊对脑缺血损伤后大鼠学习记忆能力的恢复有明显的促进作用,能使神经可塑性相关蛋白表达上调,降低大鼠海马组织NOS活性和NO含量。

硫酸软骨素酶ABC对大鼠急性脊髓损伤后神经中丝和胶质纤维酸性蛋白的影响

目的:探讨硫酸软骨素酶ABC(ChABC)对大鼠急性脊髓损伤后神经中丝200(NF200)和胶质纤维酸性蛋白(GFAP)的影响。方法:SD大鼠72只,雌雄不限,随机分为假手术组(A组)、损伤对照组(B组)和ChABC治疗组(C组),每组24只。A组仅打开椎板及置管,不损伤脊髓,不给药;C组和B组均采用Allen′s法制作大鼠T10脊髓损伤模型,分别在伤后即刻和随后每天1次连续1周蛛网膜下腔注射ChABC(6μl/次)和等量生理盐水。术后1d、1周、2周和4周每组各处死6只大鼠,B组和C组以损伤区为中心、A组在相应部位切取1cm长的脊髓组织,以HE染色观察脊髓组织形态变化,应用免疫组化方法检测脊髓组织中NF200和GFAP的变化。结果:HE染色示A组脊髓无胶质细胞增生和胶质瘢痕形成;B、C组脊髓损伤区有胶质细胞增生和胶质瘢痕,C组明显少于B组。A组术后1d、1周、2周和4周时NF200阳性细胞数及灰度值和GFAP染色阳性面积无差异,1、2、4周时B、C组脊髓损伤区NF200染色阳性细胞数及灰度值和GFAP染色阳性面积均较A组显著增加(P<0.05或P<0.01),1d和1周时C组NF200染色阳性细胞数及灰度值与B组比较无显著性差异,2周和4周时C组明显高于B组(P<0.05);1d、1周和4周时C组GFAP染色阳性面积与B组无显著性差异,2周时C组显著小于B组(P<0.05)。结论:ChABC能提高大鼠急性脊髓损伤后神经细胞内NF200的表达并抑制GFAP的表达,进而促进神经细胞的修复,抑制胶质细胞的增生和胶质瘢痕的形成,对脊髓损伤具有保护作用。

硫酸软骨素酶ABC对大鼠脊髓损伤后神经元修复的影响

目的探讨硫酸软骨素酶ABC(ChABC)对脊髓损伤后神经元修复的影响。方法SD大鼠72只,雌雄不限,随机分为假手术组、生理盐水对照组和ChABC治疗组,采用Allen法打击大鼠胸10脊髓损伤模型,分别在伤后即刻和随后每天1次连续1周蛛网膜下注射生理盐水和ChABC。在伤后第1天,第1、2、4周应用免疫组化检测各组组织切片中NF200的变化,尼氏染色观测各组脊髓切片中尼氏体和神经元的改变,BBB评分检测损伤的后肢运动恢复情况。结果大鼠脊髓损伤后1d和1周给药组NF200着色面积、Nissl染色阳性细胞和BBB评分与生理盐水组比较差异无统计学意义。在2、4周,治疗组要显著优于生理盐水组(P<0.05)。结论ChABC能促进大鼠脊髓损伤后神经元的修复,提高后肢运动功能的恢复。