Active migration of immature neurons occurs when fragments of human foetal cerebral tissues are explanted as organotypic cultures. The sequence of events during neuronal migration is orderly and consistent under different cultural conditions as evidenced by continuous time-lapse cinematographic studies. Migrating neurons utilize astrocytes to anchor neurites, and move in clusters on or along the processes of astrocytes or other neurons. Translocation of neuronal soma is accomplished by nuclear movement within extended neurites. A unique junction develops between neurites and astrocytic membrane during early phases in culture to suggest a special affinity of neurons to astrocytes. It is concluded from these observations that immature neurons have inherent capacity for active migration in-vitro; preferentially utilize astrocytes and astrocytic processes for anchoring as well as for directional guidance during migration; and translocate their soma by nuclear movement within extended neurites. It is suggested that similar mechanisms may be at play during migration of postmitotic neurons in developing cerebral cortex in human.
Astrocytes/cytology ; Brain/cytology ; Brain/embryology* ; Cell Movement ; Fetus ; Human ; Neural Conduction ; Neurons/cytology* ; Tissue Culture

Altitude ; Animals ; Astrocytes ; cytology ; Brain ; cytology ; Hypoxia ; Male ; Microglia ; cytology ; Rats ; Rats, Wistar

OBJECTIVE: To investigate the distribution and morphology of olivocochlear neurons of superior olivary complex in cats. METHODS: Eight adult cats were divided into 2 groups randomly. Cholera toxin B subunit was injected to the left cochlea and fluoro-gold was injected to the right cochlea in the experimental group (n=5). Saline was injected to bilateral cochlea in the control group (n=3). Brainstem tissue was sectioned serially. All of the sections were immunohistochemically treated with ABC and stained with DAB, and then the labelled olivocochlear neurons were observed. RESULTS: The labelled olivocochlear neurons in the experimental group were 2 518 in total. Of them, the number of lateral olivocochlear (LOC) neurons was 1 738 (69.0%), mainly located in the middle of the pons, predominantly projected ipsilaterally. The total of medial olivocochlear (MOC) neurons was 780 (31%), mainly located in dorsomedial periolivary nucleus, medial nucleus of the trapezoid body and ventral nucleus of the trapezoid body, mainly distributed in the rostral extent of the pons, predominantly projected contralaterally. CONCLUSION In the distribution of olivocochlear neurons in cats, LOC neurons mainly project to the ipsilateral. While the projection of MOC neurons is predominantly contralateral, the distribution of MOC neurons is more adjacent to the rostral extent of the pons than LOC neurons.
Animals ; Auditory Pathways ; cytology ; Brain Stem ; cytology ; Cats ; Cholera Toxin ; administration & dosage ; Cochlea ; innervation ; Cochlear Nucleus ; cytology ; Female ; Injections ; Male ; Neurons ; cytology ; Neurons, Efferent ; cytology ; Olivary Nucleus ; cytology

The aim of this study is to establish a method to culture and purify cerebral astrocyte of tree shrew (Tupaia belangeri), a kind of new laboratorial animal which is a relative of primates. Newborn tree shrews were used in this experiment. The cortex of cerebrum was isolated and placed in 4°C for 20 min to injure neurons. The cortical tissue was disaggregated by trypsin digestion. Differential attachment method was used to remove fibroblasts. The mixed culture was rinsed by trypsin (0.005%) solution to remove neurons. Upon reaching 70% confluence, the culture was subjected to static trypsin digestion until a white slice film exfoliated from the bottom of culture bottle. This film, i.e. astrocyte layer, was taken out and cultured, and the third passage was identified by immunocytochemical staining and immunofluorescence with anti-glial fibrillary acidic protein (GFAP) antibody. The result showed the purity of tree shrew astrocytes was more than 98%. Thus the method to culture highly purified astrocyte of tree shrew was successfully established, which would contribute to further study in central nervous system physiology and diseases in this new laboratorial animal.
Animals ; Astrocytes ; cytology ; Brain ; cytology ; Cell Separation ; methods ; Primary Cell Culture ; methods ; Tupaiidae

Many in vivo and in vitro studies have demonstrated the targeted migration of neural stem cells (NSC) to infiltrating brain tumors, including malignant glioma, highlighting a potential therapeutic approach. However, there is not enough information to apply this approach to clinical therapy. The most important things in stem cell therapy for brain tumors involve selecting the appropriate neural progenitor type and optimizing the efficiency of the cell engraftment. By histological analysis using two different live-dyes, human NSCs were shown to migrate away from the transplanted site in the direction of the expanding C6 glioma and to intermix with the tumor bed, especially with the tumor core. This intermixing occurred within 7 days when NSCs were implanted into glioma model. The time course of migratory HB1.F5 with the greatest mobility of three NSC lines was as follows. As early as 3 days after transplantation, several NSCs were found leaving the implant site, primarily approaching microsatellites and frontier cells located near the site of NSC implantation. Through 7 days post-transplantation, massive numbers of NSCs continued to be attracted to and interspersed with C6 glioma, and were finally distributed extensively throughout the whole tumor bed, including the core and penumbra of the tumor mass. However, NSCs appeared to penetrate into the tumor mass very well, whereas normal fibroblast cells could not migrate. These findings strengthen the potential for human NSCs as attractive vehicles to improve therapeutic gene delivery to cancer or glioma if they are optimized to selectively kill neoplastic cells.
Animals ; Brain/*cytology/*pathology ; Brain Neoplasms/*pathology ; *Cell Movement ; Female ; Glioma/*pathology ; Humans ; Mice ; NIH 3T3 Cells ; Neurons/*cytology ; Rats ; Rats, Sprague-Dawley ; Stem Cells/*cytology

The neural stem cells in Wistar rats were cultured in vitro, purified, and transplanted into C6 glioma model in order to observe their biological characters and provide a basic foundation for treatment of neurological diseases by neural stem cell transplantation. The cells at hippocampal area from gestation 15-day rats were cultured in vitro, and frozen and preserved in liquid nitrogen. C6 tumor-bearing models (n=25) and neural stem cells transplantation models (n=35) were established. When the tumor grew to 3 to 4 weeks, 5 rats in each group were randomly selected for MRI examination. At different intervals, the rats were perfused and sampled for HE staining, GFAP and BrdU immunohistochemical staining. The results showed that after resuscitation of neural stem cells at 1-4 passages, the cell viability was 40%-63% with the difference being not significant. The cells could proliferate, passage, and most cells transplanted into glioma model survived. The mean survival time in neural stem cell transplantation group and control was 4.28 and 3.88 weeks respectively, and the average tumor size in the former was smaller than in the latter. It was concluded that embryonic neural stem cells in rats could proliferate and differentiate, and after resuscitation the biological characteristic and viability of the cells were not influenced. Neural stem cells had inhibitory effects on the growth of glioma cells and could prolong the survival of rat model.
Brain/cytology ; Brain Neoplasms/*therapy ; Cells, Cultured ; Embryonic Stem Cells/cytology ; Embryonic Stem Cells/*transplantation ; Glioma/*therapy ; Neoplasm Transplantation ; Neurons/*cytology ; Random Allocation ; Rats, Wistar ; Stem Cell Transplantation

OBJECTIVETo simulate the chemical microenvironment of injured brain tissue, and to explore the effect of this chemical microenvironment on temperature sensitive umbilical cord mesenchymal stem cells (tsUC).

METHODSRat models of traumatic brain injury (TBI) were made by fluid percussion injury, and then the brain tissue extracts of the injured regions were acquired. Human umbilical cord mesenchymal stem cells (UC) were isolated and cultured, and the tsUC were obtained through the infection of temperature-sensitive Simian 40 Large T- antigen (ts-SV40LT) retrovirus. After that, both the two kinds of cells were cultured on the polyacrylamide gels which mimicking the elastic modulus of brain. Four groups were included: UC cultured under normal temperature (UC group), UC cultured added brain tissue extract under normal temperature (UC plus extract group), tsUC cultured under mild hypothermia (tsUC group), and tsUC added brain tissue extract under mild hypothermia for 3 days, then normal temperature for 4 days (tsUC plus extract group). After 24 hours, the apoptosis level was checked. Cell growth and morphological changes in each group were given dynamic observation. Seven days later, cell immunofluorescences were implemented for examining neural differentiation level.

RESULTSCompared with UC plus extract group, the apoptosis and proliferation in UC plus extract group were significantly reduced (P < 0.01) and increased (P < 0.01) respectively. Cell immunofluorescence showed that the both GFAP and Neuron positive cells were significantly enhanced in UC plus extract group than those in tsUC plus extract group.

CONCLUSIONtsUC combining with mild hypothermia could significantly reverse injury induced cell apoptosis, improve cell proliferation and neural differentiation under chemical microenvironment after brain injury, which confirmed the adaptation and resistance of tsUC under mild hypothermia after TBI.

Animals ; Apoptosis ; Brain ; cytology ; pathology ; Brain Injuries ; pathology ; Cell Proliferation ; Humans ; Mesenchymal Stromal Cells ; chemistry ; Neurons ; cytology ; Rats ; Temperature ; Umbilical Cord ; cytology

Traumatic brain injury (TBI) is a major cause of mortality and morbidity in the world. Recent clinical investigations and basic researches suggest that strategies to improve angiogenesis following TBI may provide promising opportunities to improve clinical outcomes and brain functional recovery. More and more evidences show that circulating endothelial progenitor cells (EPCs), which have been identified in the peripheral blood, may play an important role in the pathologic and physiological angiogenesis in adults. Moreover, impressive data demonstrate that EPCs are mobilized from bone marrow to blood circulation in response to traumatic or inflammatory stimulations. In this review, we discussed the role of EPCs in the repair of brain injury and the possible therapeutic implication for functional recovery of TBI in the future.
Blood-Brain Barrier ; Brain Injuries ; physiopathology ; therapy ; Endothelial Cells ; cytology ; Humans ; Neurogenesis ; Stem Cells ; physiology

We have tracked the response of host and transplanted neural progenitors or stem cells to hypoxic-ischemic (HI) brain injury, and explored the therapeutic potential of neural stem cells (NSCs) injected into mice brains subjected to focal HI injury. Such cells may integrace appropriately into the degenerating central nervous system (CNS), and showed robust engraftment and foreign gene expression within the region of HI inury. They appeared to have migrated preferentially to the site of ischemia, experienced limited proliferation, and differentiated into neural cells lost to injury, trying to repopulate the damaged brain area. The transplantation of exogenous NSCs may, in fact, augment a natural self-repair process in which the damaged CNS "attempts" to mobilize its own pool of stem cells. Providing additional NSCs and trophic factors may optimize this response. Therefore, NSCs may provide a novel approach to reconstituting brains damaged by HI brain injury. Preliminary data in animal models of stroke lends support to these hypotheses.
Animal ; Brain/pathology ; Brain Diseases/therapy* ; Brain Diseases/pathology ; Brain Ischemia/therapy* ; Brain Ischemia/pathology ; Gene Therapy* ; Human ; Nerve Tissue/cytology* ; Stem Cells/transplantation* ; Tissue Therapy*

Vascular endothelial growth factor (VEGF) was originally recognized as a substance predominantly with vascular permeability and angiogenesis. Recently, more and more evidence indicated that VEGF is expressed in the neurons of the developing and adult brains. Functional investigation demonstrated that VEGF shows several important effects on the neuronal development and physiological function. For example, VEGF accelerates the development of neurons and neural dendritic and axon growth. Besides, VEGF directly and acutely regulates the functions of multiple ion channels of the neuron membrane and changes neural excitability. In traumatic or ischemic injured brains, VEGF produces neuroprotection, enhances capacity of adult neurogenesis and transformation of astroglial cells into new neurons, which are fundamental basis for re-establishment of neural network. Based on the knowledge obtained from the literatures, we propose that VEGF may play very important roles in neural plasticity in the normal brain, and the reconstruction of neurovascular units and neural repair in the traumatic injured brain. This review mainly focuses on neural activity and repair roles of VEGF in adult mammalian brains. Further study on the mechanism of VEGF's neurobiological effects in the brain will be helpful for understanding the regulation of brain functions and developing new therapeutic strategy for prevention of neurodegeneration of the brain.
Animals ; Astrocytes ; cytology ; Brain Injuries ; physiopathology ; Humans ; Neurogenesis ; Neuronal Plasticity ; Neurons ; cytology ; Vascular Endothelial Growth Factor A ; physiology