Application of Planarian Brain Regeneration: Detection of Water Pollution

Due to over industrialisation, the environmental pollution problem is becoming increasingly serious, especially in aquatic ecosystems. Compared with traditional physical and chemical detection methods, the use of biological indicators has become popular. The freshwater planarian Dugesia japonica is distributed extensively in aquatic ecosystems and has been applied to the area of environmental toxicology for its high chemical sensitivity. Moreover, D. japonica also has a powerful regenerative capability in which the injured planarian can regenerate a new brain in 5 days and complete an adult individual remodelling in 14 days. Therefore, it has been used as a new model organism in the field of neuro-regeneration toxicology. In our past study, D. japonica can be used as a biological indicator to detect water pollution. This can provide basic data for the detection of water pollution and provide a warning system in regard to aquatic ecosystems.

Shifting balance from neurodegeneration to regeneration of the brain: a novel therapeutic approach to Alzheimer's disease and related neurodegenerative conditions

Neurodegeneration is one of the biggest public health problems in modern society. Age-associated neurodegeneration, which is accelerated several-fold in Alzheimer＇s disease （AD） alone, is not only an enormous social and economic burden to the affected in- dividuals and their families, but is also a great scientific challenge. Currently 25-35 million people worldwide suffer from AD, the single largest cause of dementia in middle- to old-aged individuals. These numbers are projected to triple by 2050 if no treatment to prevent or reverse AD is developed.

Astroglial heterogeneity:merely a neurobiological question? Or an opportunity for neuroprotection and regeneration after brain injury?

Pioneer studies by Ramon y Cajal in the early nineteenth century evidenced that astrocytes are a heterogeneous cell population. The initial division of the glial family proposed by Rudolf Albert von Kolliker and William Lloyd Andriezen that separated glia into two groups, fibrous glia and protoplasmic glia, was further refined by Ramon y Cajal,

The potential of neural transplantation for brain repair and regeneration following traumatic brain injury

Traumatic brain injury is a major health problem worldwide. Currently, there is no effective treatment to improve neural structural repair and functional recovery of patients in the clinic. Cell transplantation is a potential strategy to repair and regenerate the injured brain. This review article summarized recent development in cell transplantation studies for post-traumatic brain injury brain repair with varying types of cell sources. It also discussed the potential of neural transplantation to repair/promote recovery of the injured brain following traumatic brain injury.

Repair and regeneration properties of Ginkgo biloba after ischemic brain injury

The irretrievable fate of neurons rhetoric for the first half of this dominated the neuroscience century, a position that was fiercely contested and recently debunked by extensive studies carried out in the field of neuroregeneration research. The turning point came in the year 1928, when Ramon Y. Cajal＇s （Lobato, 2008） work suggested that the regenerative capacity of neurons, though limited, could exist beyond their physical be- ing and depended on the environment surrounding them. That the manipulation of the restrictive environment surrounding the neuron could aid the regenerative process was conclusively established by Aguayo and colleagues （Richardson et al., 1980）. Since then, various strategies have been employed to target the different phases of regeneration which include： cell-replacement and augmenting endogenous neurogenesis, the use of trophic factors, reversal of the inhibitory cues, and induction of signal- ing pathways that stimulate axon growth and guidance （Horner and Gage. 2000）.

Editor's Choice——Acupuncture and neural regeneration after brain ischemia

Acupuncture at acupoints can improve the functions of distal organs. Neuropathological studies have shown that electroacupuncture can significantly reduce the infarct volume, and improve the proportions of injured corpus striatum cells and residual cortical cells. Acupuncture-like sense stimulation can activate various conduction pathways that induce changes in nervous system activities.

Functional regeneration of the brain:white matter matters

In the human brain, white matter makes up about 50% of the brain volume and consumes 43.8% of the brain＇s total energy budget for resting potential maintenance （Harris and Attwell, 2012）. Composed of primarily myelinated axons, the white matter is the ＂highways and subways of the brain＂ connecting one region to another and trafficking in and out of the grey matter. In the myelinated nerve fibers, layers of myelin sheaths wrap around each axon to provide protection and insulation to the axon and to allow rapid conduction of action potentials. Myelin establishment and maintenance is considered a crucial requirement for fully functional con- nections between neurons in the central nerve system （CNS）.

Combined treatment promotes the long-range axon regeneration to right brain targets

Axons in the peripheral nervous system(PNS)can regenerate after injury.However,the adult mammalian central nervous system(CNS)loses the intrinsic regrowth ability.No robust axon regeneration occurs spontaneously after nerve injury,which was clearly observed by Ramon y Cajal in the early 20^(th) century(1,2).Due to lack

Breviscapine reduces neuronal injury caused by traumatic brain injury insult:partly associated with suppression of interleukin-6 expression

Breviscapine,extracted from the herb Erigeron breviscapus,is widely used for the treatment of cardiovascular diseases,cerebral infarct,and stroke,but its mechanism of action remains unclear.This study established a rat model of traumatic brain injury induced by controlled cortical impact,and injected 75 μg breviscapine via the right lateral ventricle.We found that breviscapine significantly improved neurobehavioral dysfunction at 6 and 9 days after injection.Meanwhile,interleukin-6 expression was markedly down-regulated following breviscapine treatment.Our results suggest that breviscapine is effective in promoting neurological behavior after traumatic brain injury and the underlying molecular mechanism may be associated with the suppression of interleukin-6.

Umbilical cord-derived mesenchymal stem cell transplantation combined with hyperbaric oxygen treatment for repair of traumatic brain injury

Transplantation of umbilical cord-derived mesenchymal stem cells（UC-MSCs） for repair of traumatic brain injury has been used in the clinic. Hyperbaric oxygen（HBO） treatment has long been widely used as an adjunctive therapy for treating traumatic brain injury. UC-MSC transplantation combined with HBO treatment is expected to yield better therapeutic effects on traumatic brain injury. In this study, we established rat models of severe traumatic brain injury by pressurized fluid（2.5–3.0 atm impact force）. The injured rats were then administered UC-MSC transplantation via the tail vein in combination with HBO treatment. Compared with monotherapy, aquaporin 4 expression decreased in the injured rat brain, but growth-associated protein-43 expression, calaxon-like structures, and CM-Dil-positive cell number increased. Following combination therapy, however, rat cognitive and neurological function significantly improved. UC-MSC transplantation combined with HBO therapyfor repair of traumatic brain injury shows better therapeutic effects than monotherapy and significantly promotes recovery of neurological functions.

Increased CD133^+ cell infiltration in the rat brain following fluid percussion injury

The prominin-1/CD133 epitope is expressed in craniocerebral trauma in animal models of fluid undifferentiated cells. Studies have reported that percussion injury induces production of a specific stem cell subgroup. It has been hypothesized that fluid percussion injury induces CD133＋ cell infiltration in the brain tissue. The present study established a traumatic brain injury model through fluid percussion injury. Immunohistochemical staining showed significantly increased CD133 antigen expression in the rat brain following injury. CD133＋ cells were mainly distributed in hippocampal CA1 3 regions, as well as the dentate gyrus and hilus, of the lesioned hemisphere. Occasional cells were also detected in the cortex. In addition, reverse transcription-PCR revealed that no change in CD133 mRNA expression in injured brain tissue. These results suggested that fluid percussion injury induced CD133 antigen expression in the brain tissues as a result of conformational epitope changes, but not transcriptional expression.

Does progesterone show neuroprotective effects on traumatic brain injury through increasing phosphorylation of Akt in the hippocampus?

There are currently no federally approved neuroprotective agents to treat traumatic brain injury. Progesterone, a hydrophobic steroid hormone, has been shown in recent studies to exhibit neu-roprotective effects in controlled cortical impact rat models. Akt is a protein kinase known to play a role in cell signaling pathways that reduce edema, inlfammation, apoptosis, and promote cell growth in the brain. This study aims to determine if progesterone modulates the phosphor-ylation of Aktvia its threonine 308 phosphorylation site. Phosphorylation at the threonine 308 site is one of several sites responsible for activating Akt and enabling the protein kinase to carry out its neuroprotective effects. To assess the effects of progesterone on Akt phosphorylation, C57BL/6 mice were treated with progesterone （8 mg/kg） at 1 （intraperitonally）, 6, 24, and 48 hours （subcutaneously） post closed-skull traumatic brain injury. The hippocampus was harvest-ed at 72 hours post injury and prepared for western blot analysis. Traumatic brain injury caused a signiifcant decrease in Akt phosphorylation compared to sham operation. However, mice treat-ed with progesterone following traumatic brain injury had an increase in phosphorylation of Akt compared to traumatic brain injury vehicle. Our ifndings suggest that progesterone is a viable treatment option for activating neuroprotective pathways after traumatic brain injury.

Vascular endothelial growth factor: an attractive target in the treatment of hypoxic/ischemic brain injury

Cerebral hypoxia or ischemia results in cell death and cerebral edema, as well as other cellular reactions such as angiogenesis and the reestablishment of functional microvasculature to promote recovery from brain injury. Vascular endothelial growth factor is expressed in the central nervous system after hypoxic/ischemic brain injury, and is involved in the process of brain repair via the regulation of angiogenesis, neurogenesis, neurite outgrowth, and cerebral edema, which all require vascular endothelial growth factor signaling. In this review, we focus on the role of the vascular endothelial growth factor signaling pathway in the response to hypoxic/ischemic brain injury, and discuss potential therapeutic interventions.

Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

Brain-derived neurotrophic factor（BDNF） plays an important role in the repair of central nervous system injury,but cannot directly traverse the blood-brain barrier.Liposomes are a new type of non-viral vector,able to carry macromolecules across the blood-brain barrier and into the brain.Here,we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin（Tf） and polyethylene glycol（PEG）,and carrying BDNF modified with cytomegalovirus promoter（pC MV） or glial fibrillary acidic protein promoter（p GFAP）（Tf-p CMV-BDNF-PEG and Tf-p GFAP-BDNF-PEG,respectively）.Both liposomes were able to traverse the blood-brain barrier,and BDNF was mainly expressed in the cerebral cortex.BDNF expression in the cerebral cortex was higher in the Tf-p GFAP-BDNF-PEG group than in the Tf-p CMV-BDNF-PEG group.This study demonstrates the successful construction of a non-virus targeted liposome,Tf-p GFAP-BDNF-PEG,which crosses the blood-brain barrier and is distributed in the cerebral cortex.Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain.

Axon regeneration impediment: the role of paired immunoglobulin-like receptor B

Regenerative capacity is weak after central nervous system injury because of the absence of an enhancing microenvironment and presence of an inhibitory microenvironment for neuronal and axonal repair. In addition to the Nogo receptor（Ng R）, the paired immunoglobulin-like receptor B（Pir B） is a recently discovered coreceptor of Nogo, myelin-associated glycoprotein, and myelin oligodendrocyte glycoprotein. Concurrent blocking of Ng R and Pir B almost completely eliminates the inhibitory effect of myelin-associated inhibitory molecules on axonal regeneration. Pir B participates in a key pathological process of the nervous system, specifically axonal regeneration inhibition. Pir B is an inhibitory receptor similar to Ng R, but their effects are not identical. This study summarizes the structure, distribution, relationship with common nervous system diseases, and known mechanisms of Pir B, and concludes that Pir B is also distributed in cells of the immune and hematopoietic systems. Further investigations are needed to determine if immunomodulation and blood cell migration involve inhibition of axonal regeneration.

Ischemic postconditioning protects against ischemic brain injury by up-regulation of acid-sensing ion channel 2a

Ischemic postconditioning renders brain tissue tolerant to brain ischemia,thereby alleviating ischemic brain injury.However,the exact mechanism of action is still unclear.In this study,a rat model of global brain ischemia was subjected to ischemic postconditioning treatment using the vessel occlusion method.After 2 hours of ischemia,the bilateral common carotid arteries were blocked immediately for 10 seconds and then perfused for 10 seconds.This procedure was repeated six times.Ischemic postconditioning was found to mitigate hippocampal CA1 neuronal damage in rats with brain ischemia,and up-regulate acid-sensing ion channel 2a expression at the m RNA and protein level.These findings suggest that ischemic postconditioning up-regulates acid-sensing ion channel 2a expression in the rat hippocampus after global brain ischemia,which promotes neuronal tolerance to ischemic brain injury.

Modulatory effects of acupuncture on brain networks in mild cognitive impairment patients

Functional magnetic resonance imaging has been widely used to investigate the effects of acupuncture on neural activity. However, most functional magnetic resonance imaging studies have focused on acute changes in brain activation induced by acupuncture. Thus, the time course of the therapeutic effects of acupuncture remains unclear. In this study, 32 patients with amnestic mild cognitive impairment were randomly divided into two groups, where they received either Tiaoshen Yizhi acupuncture or sham acupoint acupuncture. The needles were either twirled at Tiaoshen Yizhi acupoints, including Sishencong（EX-HN1）, Yintang（EX-HN3）, Neiguan（PC6）, Taixi（KI3）, Fenglong（ST40）, and Taichong（LR3）, or at related sham acupoints at a depth of approximately 15 mm, an angle of ± 60°, and a rate of approximately 120 times per minute. Acupuncture was conducted for 4 consecutive weeks, five times per week, on weekdays. Resting-state functional magnetic resonance imaging indicated that connections between cognition-related regions such as the insula, dorsolateral prefrontal cortex, hippocampus, thalamus, inferior parietal lobule, and anterior cingulate cortex increased after acupuncture at Tiaoshen Yizhi acupoints. The insula, dorsolateral prefrontal cortex, and hippocampus acted as central brain hubs. Patients in the Tiaoshen Yizhi group exhibited improved cognitive performance after acupuncture. In the sham acupoint acupuncture group, connections between brain regions were dispersed, and we found no differences in cognitive function following the treatment. These results indicate that acupuncture at Tiaoshen Yizhi acupoints can regulate brain networks by increasing connectivity between cognition-related regions, thereby improving cognitive function in patients with mild cognitive impairment.

Decoding brain responses to pixelized images in the primary visual cortex: implications for visual cortical prostheses

Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only ＂see＂ pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex（the implant area） is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine（LSVM） as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.

Evidence for novel age-dependent network structures as a putative primo vascular network in the dura mater of the rat brain

With chromium-hematoxylin staining, we found evidence for the existence of novel age-dependent network structures in the dura mater of rat brains. Under stereomicroscopy, we noticed that chromium-hematoxylin-stained threadlike structures, which were barely observable in 1-weekold rats, were networked in specific areas of the brain, for example, the lateral lobes and the cerebella, in 4-week-old rats. In 7-week-old rats, those structures were found to have become larger and better networked. With phase contrast microscopy, we found that in 1-week-old rats, chromium-hematoxylin-stained granules were scattered in the same areas of the brain in which the network structures would later be observed in the 4- and 7-week-old rats. Such age-dependent network structures were examined by using optical and transmission electron microscopy, and the following results were obtained. The scattered granules fused into networks with increasing age. Cross-sections of the age-dependent network structures demonstrated heavily-stained basophilic substructures. Transmission electron microscopy revealed the basophilic substructures to be clusters with high electron densities consisting of nanosized particles. We report these data as evidence for the existence of age-dependent network structures in the dura mater, we discuss their putative functions of age-dependent network structures beyond the general concept of the dura mater as a supporting matrix.

Cell proliferation and apoptosis in optic nerve and brain integration centers of adult trout Oncorhynchus mykiss after optic nerve injury

Fishes have remarkable ability to effectively rebuild the structure of nerve cells and nerve fibers after central nervous system injury.However,the underlying mechanism is poorly understood.In order to address this issue,we investigated the proliferation and apoptosis of cells in contralateral and ipsilateral optic nerves,after stab wound injury to the eye of an adult trout Oncorhynchus mykiss.Heterogenous population of proliferating cells was investigated at 1 week after injury.TUNEL labeling gave a qualitative and quantitative assessment of apoptosis in the cells of optic nerve of trout 2 days after injury.After optic nerve injury,apoptotic response was investigated,and mass patterns of cell migration were found.The maximal concentration of apoptotic bodies was detected in the areas of mass clumps of cells.It is probably indicative of massive cell death in the area of high phagocytic activity of macrophages/microglia.At 1 week after optic nerve injury,we observed nerve cell proliferation in the trout brain integration centers：the cerebellum and the optic tectum.In the optic tectum,proliferating cell nuclear antigen（PCNA）-immunopositive radial glia-like cells were identified.Proliferative activity of nerve cells was detected in the dorsal proliferative（matrix） area of the cerebellum and in parenchymal cells of the molecular and granular layers whereas local clusters of undifferentiated cells which formed neurogenic niches were observed in both the optic tectum and cerebellum after optic nerve injury.In vitro analysis of brain cells of trout showed that suspension cells compared with monolayer cells retain higher proliferative activity,as evidenced by PCNA immunolabeling.Phase contrast observation showed mitosis in individual cells and the formation of neurospheres which gradually increased during 1–4 days of culture.The present findings suggest that trout can be used as a novel model for studying neuronal regeneration.