脑缺血大鼠脑皮层中强啡肽A(1-13)的经时表达及脑含水量的变化

目的研究局灶性脑缺血大鼠脑皮层中强啡肽A(1-13)的经时表达及脑含水量的变化。方法用线栓法建立大鼠大脑中动脉梗塞模型,用免疫组织化学方法观察脑缺血组大鼠及假手术对照组大鼠缺血侧及非缺血侧脑皮层强啡肽A(1-13)在脑缺血100 min后再灌注4、8、24 h的表达及脑含水量的变化。结果假手术对照组大鼠缺血侧及非缺血侧脑皮层表达强啡肽A(1-13)的细胞数分别是每高倍镜视野(60.2±5.1)个及(61.1±3.9)个,在脑缺血后再灌注4、82、4 h大鼠缺血侧及非缺血侧脑皮层的强啡肽A(1-13)表达细胞数分别是每高倍镜视野(39.3±6.2)个及(60.3±3.7)个、(41.5±5.8)个及(60.1±3.9)个、(25.2±5.1)个及(59.6±5.9)个;而脑缺血后再灌注4、8、24 h的缺血侧含水量逐渐增加。结论大鼠脑缺血后缺血侧脑皮层的强啡肽A(1-13)表达逐渐减少而含水量逐渐增加。

脑缺血大鼠脑组织中强啡肽A(1-8)含量及含水量的变化

目的:探讨局灶性脑缺血大鼠脑皮层及纹状体中强啡肽A(1-8)含量及含水量的变化。方法:用线栓法建立大鼠大脑中动脉阻塞(MCAO)模型,用放免法观察假手术对照组大鼠及脑缺血组大鼠缺血侧脑皮层及纹状体中强啡肽A(1-8)在100min,MCAO后、再灌注8h及24h含量的变化,并测定缺血侧脑皮层及纹状体含水量的变化。结果:假手术对照组大鼠及脑缺血再灌注8h大鼠缺血侧脑皮层强啡肽A(1-8)含量分别是5.58±0.61pmol/g及3.51±0.43pmol/g;缺血侧纹状体强啡肽A(1-8)含量分别是7.72±0.92pmol/g及5.62±0.71pmol/g。假手术对照组大鼠及脑缺血再灌注24h大鼠缺血侧脑皮层强啡肽A(1-8)含量分别是5.43±0.52pmol/g及2.41±0.32pmol/g;缺血侧纹状体强啡肽A(1-8)含量分别是7.59±0.88pmol/g及4.35±0.63pmol/g。随再灌注时间的延长,脑缺血组大鼠缺血侧脑皮层及纹状体含水量逐渐增高。结论:局灶性脑缺血可降低缺血侧脑皮层及纹状体中的强啡肽A(1-8)含量及增高缺血侧脑皮层及纹状体的含水量。

Intrastriatal glial cell line-derived neurotrophic factors for protecting dopaminergic neurons in the substantia nigra of mice with Parkinson disease

BACKGROUND： Substantia nigra is deep in position and limited in range, the glial cell line-derived neurotrophic factor （GDNF） injection directly into substantia nigra has relatively greater damages with higher difficulty. GDNF injection into striatum, the target area of dopaminergic neuron, may protect the dopaminergic neurons in the compact part of substantia nigra through retrograde transport. OBJECTIVE： To investigate the protective effect of intrastriatal GDNF on dopaminergic neurons in the substantia nigra of mice with Parkinson disease （PD）, and analyze the action pathway. DESIGN： A controlled observation. SETTING： Neurobiological Laboratory of Xuzhou Medical College. MATERIALS： Twenty-four male Kunming mice of 7 - 8 weeks old were used. GDNF, 1-methy1-4-pheny1-1,2,3,6-tetrahydropyridine （MPTP） were purchased from Sigma Company （USA）; LEICAQWin image processing and analytical system. METHODS： The experiments were carded out in the Neurobiological Laboratory of Xuzhou Medical College from September 2005 to October 2006. The PD models were established in adult KunMing mice by intraperitoneal injection of MPTP. The model mice were were randomly divided into four groups with 6 mice in each group： GDNF 4-day group, phosphate buffer solution （PSB） 4-day group, GDNF 6-day group and PSB 6-day group. Mice in the GDNF 4 and 6-day groups were administrated with 1 μ L GDNF solution （20 μ g/L, dispensed with 0.01 mol/L PBS） injected into right striatum at 4 and 6 days after model establishment. Mice in the PSB 4 and 6-day groups were administrated with 0.01 mol/L PBS of the same volume to the same injection at corresponding time points. ② On the 12^th day after model establishment, the midbrain tissue section of each mice was divided into 3 areas from rostral to caudal sides. The positive neurons of tyroxine hydroxylase （TH） and calcium binding protein （CB） with obvious nucleolus and clear outline were randomly selected for the measurement, and the number of positive neurons in unit area was counted. MAIN OUTCOME MEASURES： Number of positive neurons of TH and CB in midbrain substantia nigra of mice in each group. RESULTS： All the 24 mice were involved in the analysis of results. The numbers of TH^＋ and CB^＋ neurons in the GDNF 4-day group （54.33±6.92, 46.33±5.54） were obviously more than those in the PBS 4-day group （27.67±5.01, 21.50±5.96, P 〈 0.01）. The numbers of TH^＋ and CB^＋ neurons in the GDNF 6-day group （75.67±5.39, 69.67±8.69） were obviously more than those in the PBS 6-day group （27.17±4.50, 21.33 ±5.72, P 〈 0.01） and those in the GDNF 4-day group （P 〈 0.01 ）. CONCLUSION： Intrastriatal GDNF can protect dopaminergic neurons in substantia nigra of PD mice, and it may be related to the increase of CB expression.

Micromechanical adaptation as a treatment for spinal cord injury

Spinal cord injury: Thus far injury of the spinal cord is incurable and, in the majority of cases, a devastating and life-changing event. The worldwide incidence rate of spinal cord injury (SCI) ranges from 250,000 to 900,000 (www.who.int, 2013;Kumar et al., 2018) new cases per year. SCI outcome includes the damage of axons, demyelination of axons, loss of signal transduction, and consequential long-lasting motor and sensory deficits. Additionally, the non-use of muscles can lead to atrophy and joint contractures, thereby further reducing the possibility of recovery. Depending on the spinal level and the severity of the injury, the extent of the damage can vary and spontaneous recovery is possible to varying degrees.

Proprotein convertase 1 mRNA and protein expression in ischemic rat cortex after reperfusion

Proprotein convertase 1 （PC1） is a member of the family of proprotein convertases （PCs）, which are the processing enzymes of neuropeptides. Previous studies have addressed PC1 effects with regard to the neuroendocrine system. In this study, the developing changes of PC1 mRNA and PC1 protein in rat cortices after transient focal cerebral ischemia were investigated by fluorescent double labeling （both in situ hybridization and immunocytochemistry） using a transient focal cerebral ischemia model in rats. The results were compared with those of sham-operated rat cortices. Both the mRNA and protein levels of PC1 in ischemic cortices decreased gradually at 4, 8, and 16 hours of reperfusion after 100 minutes of middle cerebral artery occlusion. After 24 hours of reperfusion, enhanced intensities of signals for PC1 protein were observed, while signals for PC1 mRNA remained low. These results suggest that transient focal cerebral ischemia influences PC1 mRNA and protein expression in cortices of ischemic rats. Thus, PC1 is regulated by ischemic stress.

A novel mode of retinal regeneration:the merit of a new Xenopus model

Retinal regeneration： The retina is a part of the central nervous system （CNS） and has long attracted neurobiologists as an excellent model organ for the study of CNS regeneration. In classical studies using urodele amphibians like the salamander newt, it has been shown that the retina regenerates after the removal of the whole tissue even in the adulthood. This type of regeneration is considered as an example of ＂transdifferentiation＇, since the source of the regenerating retina is the retinal pigmented epithelial cells （RPE cells） （Okada, 1991;

Bridging large gaps in the injured spinal cord: mechanical and biochemical tissue adaptation

Incidence and consequences of spinal cord injuries： World- wide, every year 250,000-500,000 people suffer from spinal cord injury （SCI; www.who.int, 2013）. Traumatic lesions of the spinal cord lead to primary and secondary injury mechanisms, which result in axon damage, loss of signal conduction, demyelination of axons and long-lasting deficits in motor and sensory func- tion. The extent of the damage and the subsequent functional loss depend on the spinal level and the severity of the primary injury. Furthermore, pathophysiological and pathomorpholog- ical responses in acute and chronic SCI share similar but also different requirements for treatment.

Potassium variability during hospitalization and outcomes after discharge in patients with acute myocardial infarction

BACKGROUND The variability of metabolic biomarkers has been determined to provide incremental prognosis information,but the implications of electrolyte variability remained unclear.METHODS We investigate the relationships between electrolyte fluctuation and outcomes in survivors of acute myocardial infarction(n=4386).Ion variability was calculated as the coefficient of variation,standard deviation,variability independent of the mean(VIM)and range.Hazard ratios(HR)were estimated using the multivariable-adjusted Cox proportional regression method.RESULTS During a median follow-up of 12 months,161(3.7%)patients died,and heart failure occurred in 550(12.5%)participants after discharge,respectively.Compared with the bottom quartile,the highest quartile potassium VIM was associated with increased risks of all-cause mortality(HR=2.35,95%CI:1.36–4.06)and heart failure(HR=1.32,95%CI:1.01–1.72)independent of cardiac troponin I(c Tn I),N terminal pro B type natriuretic peptide(NT-pro BNP),infarction site,mean potassium and other traditional factors,while those associations across sodium VIM quartiles were insignificant.Similar trend remains across the strata of variability by other three indices.These associations were consistent after excluding patients with any extreme electrolyte value and diuretic use.CONCLUSIONS Higher potassium variability but not sodium variability was associated with adverse outcomes post-infarction.Our findings highlight that potassium variability remains a robust risk factor for mortality regardless of clinical dysnatraemia and dyskalaemia.

Dynamic changes in proprotein convertase 2 activity in cortical neurons after ischemia/reperfusion and oxygen-glucose deprivation

In this study, a rat model of transient focal cerebral ischemia was established by performing 100 minutes of middle cerebral artery occlusion, and an in vitro model of experimental oxygen-glucose deprivation using cultured rat cortical neurons was established. Proprotein convertase 2 activity gradually decreased in the ischemic cortex with increasing duration of reperfusion. In cultured rat cortical neurons, the number of terminal deoxynucleotidyl transferase-mediated 2＇-deoxyuridine 5＇-triphosphate-biotin nick end labeling-positive neurons significantly increased and proprotein convertase 2 activity also decreased gradually with increasing duration of oxygen-glucose deprivation. These experimental findings indicate that proprotein convertase 2 activity decreases in ischemic rat cortex after reperfusion, as well as in cultured rat cortical neurons after oxygen-glucose deprivation. These changes in enzyme activity may play an important pathological role in brain injury.

Changes in proprotein convertase subtilisin/kexin type 9 mRNA expression in rat cortex after cerebral ischemia

Oxidized low density lipoprotein is a risk factor for cerebrovascular disease. Proprotein convertase subtilisin/kexin type 9 （PCSK9） can increase the level of low density lipoprotein. Therefore, this study assumed that PCSK9 plays important roles in ischemic cerebrovascular disease. The present study established transient focal cerebral ischemia models after 100 minutes of middle cerebral artery occlusion. In situ hybridization demonstrated that PCSK9 mRNA expression increased gradually with prolonged reperfusion time in ischemic cortices. This indicated that transient focal cerebral ischemia upregulated PCSK9 mRNA expression in ischemic cortices.

Shifts in Photon Spectral Power Densities within Schumann (7.7 to 7.8 Hz) Values in Microtubules during Complex Magnetic Field Exposures May Reflect an Information Interface with Universal Energies

The specific diameter of microtubules was shown to be a primary solution when magnetic energy was set equal to Casimir energy. To discern if this spatial containment could be foci for information photon emissions were measured from preparations of microtubules (MTs) while they were exposed in sequential 4 min intervals to various patterns of weak magnetic fields whose intensities ranged from 3 to 10 μT. Calculations from the median mass of a tubulin dimer, its summed charges and the applied magnetic field as well as the change in magnetic moment derived from the energy of the hydrogen line when applied to our experimental fields predicted a dynamic shift (Δf) between 0.03 and 0.21 Hz. Spectral power densities (SPD) indicated marked enhancements in photon numbers during periods of magnetic field exposures within the 7.6 to 7.8 Hz increment. The total SPD units for the shift were 10-18 to 10-17 J per s. Five of the eight patterns elicited a split spectrum of power within this range. Separate factor analyses of the SPDs of the serial values that composed the points of the actual field patterns indicated those that evoked the split-spectrum (Δf = 0.05 to 0.13 Hz) displayed significantly higher loadings on the same factor compared to those that did not. If this shift in photon energy reflects a phase modulation of the coherence frequency (8 MHz) of MTs, the increment of energy per MHz frequency would be within the energy of the neutral hydrogen line. These results suggest that the intrinsic structure or information from specific intensity magnetic fields when applied to MTs is reflected in photon energy densities vacillating around the fundamental Schumann Resonance that could be an interface between Casimir and magnetic sources.

Development of Genetic Engineering Tools for p75ngfr Methylation and Expression Modulation

Neurotrophic factors, as well as their receptors are key players in the formation and development of the central nervous system. Like the sculptor’s incisor, they form the neural networks and circuits of the future organism. The neurotrophic growth factor receptor p75ngfr interacts with sortilin, serves as a receptor for proform of neurotrophic factors and exhibits a proapoptotic effect in developing neurons—dorsal root ganglia neurons and brainstem norepinephrine neurons. p75ngfr is highly expressed in Locus Coeruleus norepinephrine neurons. Therefore, an important task for developing further methods of CNS gene therapy is the development of tools and molecular methods for suppressing p75ngfr expression in norepinephrine neurons. For this purpose, we’ve developed improved dCas9 vectors with Suntag system to suppress gene expression and enhance methylation of CpG islands. We used 10 times repetitive GCN peptide that were fused to dCas9. Single chain antibody against GCN peptide was fused to KRAB repressor or Dnmt3a catalytic domain. Expression specificity was achieved by using a promoter consisting of 8 repeated phox2a/2b binding sites. In this work, we’ve tested a set of guide RNAs targeting p75ngfr cpg island in the promoter. Usage of Suntag system led us to the conclusion that topological orientation and length of the final complex could influence on p75ngfr antisense transcript expression, and that sequence was established in the rat P3 brainstem.

Modulation of Specific Apoptotic DNA Fragmentation after Short Term Exposure to Natural UVR in Fish Larvae

The goal of this study was to determine the short-term effects of the quality (UV-A/UV-B ratio) and quantity (irradiance) of natural ultraviolet radiation (UVR) on the apoptosis levels in Yellow perch (Perca flavescens) larvae. Apoptosis, or programmed cell death, is an essential event in many physiological processes as well as in pathological conditions. Western blots were used to measure the expression of several key proteins of the apoptotic cascade, such as p53, Bax, Bcl-2, and PARP-1, whereas specific apoptotic DNA fragmentation was measured by an ELISA assay. We predicted that higher UVR exposure would be related to higher levels of apoptosis. Our results showed that specific apoptotic DNA fragmentation was reduced by visible light + UV-A as well as by visible light + UV-A and UV-B treatments although it was not significantly affected by light quantity. However, the expression of p53, Bax/Bcl-2 ratio and PARP-1 were not significantly affected in larvae by the quantity or the quality of the light after two days of exposure. Altogether our results suggest that UVR may modulate the apoptotic process in Yellow perch larvae proposing an interesting role for this stressor on the early development of living organism under natural exposure condition.

Super-resolution microscopy and its applications in neuroscience

Optical microscopy promises researchers to soe most tiny substances directly.However,the resolution of conventional microscopy is resticted by the diffraction limit.This makes it a challenge to observe subcellular processes happened in nanoscale.The development of super-resolution microscopy provides a solution to this challenge.Here,we briefly review several commonly used super-resolution techniques,explicating their basic principles and applications in biological science,especially in neuroscience.In addition,characteristics and limitations of each techrique are compared to provide a guidance for biologists to choose the most suitable tool.

Syzygium aromaticum ethanol extract reduces AlCl_3-induced neurotoxicity in mice brain through regulation of amyloid precursor protein and oxidative stress gene expression

Objective: To investigate the neuroprotective effects of Syzygium aromaticum(S.aromaticum)extract(500 mg/kg) on AlCl_3(300 mg/kg)-induced mouse model of oxidative stress and neurotoxicity.Methods: An ethanolic extract of S.aromaticum seeds was prepared and the active compounds were identified using nuclear magnetic resonance spectroscopy.BALB/c mice were divided into five groups(negative control, AlCl_3-treated, self-recovery, AlCl_3 + S.aromaticum, S.aromaticum only; n=10) and treated with AlCl_3 and S.aromaticum extract.Expression of oxidative markers [Superoxide dismutase 1(SOD1) and peroxiredoxin 6(Prdx6)] and amyloid precursor protein(APP) in the hippocampus and cortex was evaluated via PCR.Histopathological assessment was performed to investigate the extent of neurodegeneration.Results: It was observed that AlCl_3 exposure increased the expression of APP770 while simultaneously down regulated the expression of APP695.AlCl_3 also induced a significant decrease(P<0.05) and an increase(P<0.05) in the expression level of SOD1 and Prdx6, respectively.A substantial decrease substantial(P<0.05) in the density of Nissl substance was also observed in cortex of the mice treated with AlCl_3.Interestingly, treatment with S.aromaticum extract normalized the alterations in the expression level of SOD1, Prdx6 and APPisoforms and improved the neuronal structural damage.Conclusions: The results showed that S.aromaticum is a promising antioxidant and a neuroprotective agent.

Development of the cerebellar cortex in the mouse

The cerebellum is a highly conserved structure in the central nervous system of vertebrates, and is involved in the coordination of voluntary motor behavior. Supporting this function, the cerebellar cortex presents a layered structure which requires precise spatial and temporal coordination of proliferation, migration, differentiation, and apoptosis events. The formation of the layered structure in the developing cerebellum remains unclear. The present study investigated the development of the cerebellar cortex. The results demonstrate that the primordium of the cerebellum comprises the ependymal, mantle, and marginal layers at embryonic day 12 （E12）. Subsequently, the laminated cerebellar cortex undergoes cell proliferation, differentiation, and migration, and at about postnatal day 0 （P0）, the cerebellar cortex presents an external granular layer, a molecular layer, a Purkinje layer, and an internal granular layer. The external granular layer is thickest at P6/7 and disappears at P20. From P0 to P30, the internal granular cells and the Purkinje cells gradually differentiate and develop until maturity. Apoptotic neurons are evident in the layered structure in the developing cerebellar cortex. The external granular layer disappears gradually because of cell migration and apoptosis. The cells of the other layers primarily undergo differentiation, development, and apoptosis.

Polymeric nanocarriers for nose-to-brain drug delivery in neurodegenerative diseases and neurodevelopmental disorders

Neurodegenerative diseases are progressive conditions that affect the neurons of the central nervous system(CNS)and result in their damage and death.Neurodevelopmental disorders include intellectual disability,autism spectrum disorder,and attention-deficit/hyperactivity disorder and stem from the disruption of essential neurodevelopmental processes.The treatment of neurodegenerative and neurodevelopmental conditions,together affecting~120 million people worldwide,is challenged by the blood—brain barrier(BBB)and the blood—cerebrospinal fluid barrier that prevent the crossing of drugs from the systemic circulation into the CNS.The nose-to-brain pathway that bypasses the BBB and increases the brain bioavailability of intranasally administered drugs is promising to improve the treatment of CNS conditions.This pathway is more efficient for nanoparticles than for solutions,hence,the research on intranasal nano-drug delivery systems has grown exponentially over the last decade.Polymeric nanoparticles have become key players in the field owing to the high design and synthetic flexibility.This review describes the challenges faced for the treatment of neurodegenerative and neurodevelopmental conditions,the molecular and cellular features of the nasal mucosa and the contribution of intranasal nano-drug delivery to overcome them.Then,a comprehensive overview of polymeric nanocarriers investigated to increase drug bioavailability in the brain is introduced.

Aspects of xenobiotics and their receptors in stroke

Stroke is devastating and the second leading cause of disability and death worldwide.The pathophysiology of stroke is intricate involving oxidative stress,ionic imbalance,and excitotoxicity leading to cell death.The current therapeutic strategies for ischemic stroke primarily aim to restore cerebral blood flow by removing clots using intravenous thrombolysis and mechanical thrombectomy.However,hemorrhagic stroke requires different therapeutic interventions,where intravenous thrombolysis worsens the persistent condition.Nevertheless,the present treatment strategies do not provide effective neuroprotection as they have limitations such as narrow time window,specialized clinics and personnel,and higher expense.Therefore,studies on novel therapeutic strategies that can render neuroprotection over an extended time with minimum adverse effects are solicited.Xenobiotics are agents that are foreign to the biological system but can regulate their metabolism by binding to different xenobiotic receptors(XRs)to produce toxic substances.Modulation of XRs in different preclinical studies have shown benefits in the stroke outcome.Therefore,targeting XRs may be a future therapeutic strategy for stroke intervention.The present review briefly discusses various implications of xenobiotics and their receptors to evolve as a potential therapeutic target for prospective use as an adjunctive therapy for stroke.

Cuprizone-induced demyelination in mice: age-related vulner-ability and exploratory behavior deficit

Schizophrenia is a mental disease that mainly affects young individuals （15 to 35 years old） but its etiology remains largely undefined. Recently, accumulating evidence indicated that demyelination and/or dysfunction of oligodendrocytes is an important feature of its pathogenesis. We hypothesized that the vulnerability of young individuals to demyelination may contribute to the onset of schizophrenia. In the present study, three different age cohorts of mice, i.e. juvenile （3 weeks）, young-adult （6 weeks） and middle-aged （8 months）, were subjected to a 6-week diet containing 0.2% cuprizone （CPZ） to create an animal model of acute demyelination. Then, age-related vulnerability to CPZ-induced demyelination, behavioral outcomes, and myelination-related molecular biological changes were assessed. We demonstrated： （1） CPZ treatment led to more severe demyelination in juvenile and young-adult mice than in middle-aged mice in the corpus callosum, a region closely associated with the pathophysiology of schizophrenia; （2） the higher levels of demyelination in juvenile and young-adult mice were correlated with a greater reduction of myelin basic protein, more loss of CC-1- positive mature oligodendrocytes, and higher levels of astrocyte activation; and （3） CPZ treatment resulted in a more prominent exploratory behavior deficit in juvenile and young-adult mice than in middle-aged mice. Together, our data demonstrate an age-relatedvulnerability to demyelination with a concurrent behavioral deficit, providing supporting evidence for better understanding the susceptibility of the young to the onset of schizophrenia.

The Role of Synapsins in Neurological Disorders

Synapsins serve as flagships among the presynaptic proteins due to their abundance on synaptic vesicles and contribution to synaptic communication. Several studies have emphasized the importance of this multi-gene family of neuron-specific phosphoproteins in maintaining brain physiology. In the recent times, increasing evidence has established the relevance of alterations in synapsins as a major determinant in many neurological disorders. Here,we give a comprehensive description of the diverse roles of the synapsin family and the underlying molecular mechanisms that contribute to several neurological disorders.These physiologically important roles of synapsins associated with neurological disorders are just beginning to be understood. A detailed understanding of the diversified expression of synapsins may serve to strategize novel therapeutic approaches for these debilitating neurological disorders.