جستجوی مقالات مرتبط با کلیدواژه "سلول های بنیادی عصبی" در نشریات گروه "پزشکی"

Cell therapy is a feasible method for the treatment of spinal cord injury as well as other neurological disorders. Because of the cell death reported to be in the cell transplants, the use of +scaffolds can be useful to improve cell protection, resulting in an increase in their survival and growth, and differentiation. Since alginate hydrogel biopolymer was reported to be effective in treating spinal cord lesions, in this study, we intended to evaluate the protectivity of alginate hydrogel against free radicals in the cultured neural stem cells (NSCs) induced into neuronal phenotype using valproic acid as inducer, and improvement of their survival will be assessed.

Bone marrow stromal stem cell-derived neural stem cells encapsulated in alginate hydrogel, were used in this study. The encapsulated cells were induced by valproic acid and the cells were evaluated by immunocytochemical methods and reverse-transcription polymerase chain reaction (RT-PCR). The induction of apoptosis was achieved by hydrogen peroxide (H2O2), and the cell viability was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The Protective Effect of alginate hydrogel in front of H2O2 was evaluated by Ferric Reducing Antioxidant Power (FRAP) and MTT. The control groups were two-dimensional (2-D) cultured of the induced NSCs into neuronal phenotype by valproic acid as well as induction of apoptosis by H2O2

The results showed that the viability of neuronal phenotype treated by H2O2 in alginate hydrogel was higher than that of cells cultured under the same condition in 2-D culture, also, the expression of Bcl2 and survivin was higher, while the expression of Bax was lower. Similar results were noticed with the FRAP technique

The results showed that alginate hydrogel has a protective effect on the induced NSCs into neuron-like cells, following induction of apoptosis by H2O2. The results of gene expression and FRAPwere consistent with the above results

Uncontrolled stress affects hippocampal-dependent memory through altering the morphology and the proliferation rate of the hippocampal progenitor cells.

In this experimental study, neural stem cells (NSCs) derived from rat hippocampus were extracted and cultured to produce neutrospheres in a serum-free environment. Nestin antibody was used to identification the induced NSCs. Cell proliferation and cytotoxicity due to the effect of norepinephrine were measured by MTT assay. NSCs were assigned in the following experimental groups: Control (untreated), NE (treated with norepinephrine), Pro (pretreated with beta-blocker propranolol then norepinephrine), Pra (pretreated with alfa-blocker prazosin then norepinephrine), and Syn (pretreated with propranolol and prazosin then norepinephrine). Real-time RT-PCR was conducted to quantify mRNA levels of the Stk4, Caspase-3 and Sox2.

The flow cytometry analysis revealed that NSCs were nestin positive. Real-time RT-PCR results showed that gene expression levels of Sox2 mRNA was increased via norepinephrine. Also, gene expression levels of Stk4 and Caspase-3 were increased in the group that pretreated with prazosin.

Taken together, the effect of norepinephrine on hippocampus-derived neural stem cells is receptor-dependent and, increase of norepinephrine under chronic stress can lead to the either proliferation or apoptosis in the NSCs, as a double-edged sword.

The promotion of Alzheimer’s disease contributes to the brain cell (neuron) death and synaptic dysfunction in the hippocampus. These changes continue with the neural tissue degeneration and behavioral deficits such as learning disabilities, memory loss, and cognitive impairment which coincided with the reduction of neurogenesis. As a matter of fact, applying novel therapeutic strategies have focused on neural stem cell therapies. Due to the short-time survival rate, lack of transplantation efficiency and differentiation capacity, the use of suitable microenvironment is mandatory in order to stimulate dynamic growth of neural stem cells and regeneration rate.

In the present study, articles indexed in PubMed, ISI, and Scopus databases about the application of neural stem cells in neurodegenerative diseases such as Alzheimer’s disease were reviewed. Besides, different approaches to activate and increase the recruitment of neural stem cells via mesenchymal stem cells, growth factors, scaffolds and extracellular matrix were described in the context of neuro-regeneration.

Several studies revealed that mesenchymal stem cells stimulated proliferation, recruitment, and neural differentiation of neural stem cells and improved synaptic plasticity by the production of neurotrophic factors, chemokine, and extracellular matrix. In addition, mesenchymal stem cells decreased the apoptosis phenomenon and increased cell viability via the secretion of anti-inflammatory and anti-apoptotic factors. It has been shown that the fabrication of scaffolds from natural biomaterials provides suitable and biocompatib le artificial microenvironments that are comparable to the naïve brain extracellular matrix with the potential to promote cell migration and differentiation. These approaches could alleviate the neural tissue degeneration and diminish the cognitive impairment.

The stimulation of endogenous neural stem cells recruitment using mesenchymal stem cells and different cell-related products, extracellular matrix, natural and artificial materials could protect the individuals against Alzheimer’s disease and reduce the progression of neurodegeneration, and restoration of behavioral deficits.

Recently, several studies have indicated that the central nervous system has the capacity for endogenous repair. But, the proliferation capacity of endogenous neural stem cells (NSCs) isn’t sufficient for the treatment of neurodegenerative diseases. So, it sounds that stimulation of endogenous NSC proliferation is essential for neuroregeneration. The aim of this study was to examine the effects of Sambucus ebulus extract on the proliferation of neonatal rat hippocampus-derived neural stem cells (NSCs) under oxidative stress condition induced by H2O2.
Material and The NSCs were isolated from neonatal rat hippocampus. To confirm neural characteristics of neural stem cells, the expression of neural-specific marker, Nestin was investigated by immunocytochemistry technique. 5×104 cells were cultured in every well of a 96 well plate and H2O2 was added to induce oxidative stress condition. Then NSCs were exposed to 50 µg Sambucus ebulus extract for 24 hours, at various concentrations (25, 50, 100, 200, 400 and 500 μg/ml). The cell proliferation rate was assessed by MTT colorimetry assay before and after treatment with the extract.
Immunofluorescent studies showed that neural stem cells expressed specific neural marker; Nestin. The proliferation rate of NSCs increased in the treated groups in comparison to that in the control group. The highest rate of survival was observed when Sambucus ebulus was used at the concentration of 500 μg/ml. (P The results showed that the methanolic extract of Sambucus ebulus can promote proliferation and survival of NCSs in vitro and also after exposure to oxidative stress condition, suggesting its potential beneficial effect on neuroregeneration.

Excessive production of free radicals during oxidative stress can cause serious damage to important biomolecules and activate programmed cell death pathways in the body. In the nervous system, neuronal cell death leads to many progressive neurodegenerative disorders. The aim of this study was to evaluate the effects of adenosine on the inhibition of apoptosis in oxidative damage induced by hydrogen peroxide in bone marrow derived neural stem cells (BMSCs-dNSCs). BMSCs-dNSCs were pretreated with different doses of adenosine for 48 hours and then exposed to 125μM H2O2 for 30 minutes. Using MTT and TUNEL assay, we evaluated the effects of adenosine on cell survival and apoptosis in pretreated BMSCs-dNSCs in comparison to control groups. The results showed that the apoptosis rate in the 6 µM adenosine pretreated BMSCs-dNSCs was significantly decreased compared to the control group in the condition of oxidative stress (P Our findings suggest that adenosine protects NSCs against oxidative stress induced cell death, therefore it may be used to promote the survival rate of NSCs and could be a candidate for the treatment of oxidative stress mediated neurological diseases.

Alzheimer's disease (AD) is the most common form of dementia among the elderly. Its pathohistological characteristics are the accumulation of extracellular β-amyloid protein and hyperphosphorylation of tau protein. This neurodegenerative disorder is assumed to start with synaptic dysfunction and chronic loss of neuronal cells. Researchers believe that neurogenesis appears in adulthood; therefore, replacement of the lost neurons can represent a therapeutic approach for the management and improvement of AD. The developing field of stem cell biology offers great therapeutic potential for chronic neurological conditions such as AD, particularly if joined with a multitargeted therapeutic approach. It has been shown that enriched environment positively affects patient's cognitive behaviors through various mechanisms, including modulation of neurogenesis.
The current advancements in neurogenesis, stem cells therapies, and environmental enrichment in AD are reviewed in this article, and the potential barriers to the use of these treatments for AD patients are discussed.

Nowadays, extensive research is carried out on the effect of plant extracts on variety of disorders. In this study, the effect of hydroethanolic extract of Lavandula officinalis on proliferation of neural stem cells as well as its anti-apoptotic properties was assessed.
Neural stem cells were isolated from hippocampus of neonatal rat brain. To determine the optimal concentration of Lavandula officinalis extract, isolated neural stem cells were treated with 200, 400, 600, 800 and 1000 µg/ml of concentrate for 48 h. Then cell proliferation rate was evaluated via MTT assay. Meanwhile, the anti-apoptotic property of Lavandula officinalis extract was evaluated using TUNEL assay method.
The results of this study showed a significant difference in cell proliferative and anti-apoptotic property of Lavandula officinalis extract on neural stem cells comparing to the control group.
The hydroethanolic extract of Lavandula officinalis can be effective on proliferation elevation and apoptosis reduction in rat neural stem cells.

Cell therapy is among the novel therapeutic methods effective in the treatment of spinal cord injuries. The aim of the present study was using neural stem cells (NSCs) in treating contusion spinal cord injury in rat model.
Bone marrow stromal cells (BMSCs) were isolated from adult rats. After three passages, these cells were transdifferntiated to neurospheres and subsequently to neural stem cells (NSCs). At in vivo studies, 43 adult female rats were divided into 5 groups. For the first group or Sham, laminectomy was the only procedure performed, whereas for the other four groups, after laminectomy, a contusion Spinal Cord Injury (SCI) was induced, as well. In group 2, no treatment was performed. In the other groups, injection was performed 7 days after SCI, as such: in groups 3, 4, and 5 normal saline, BMSCs, and NSCs were injected, respectively. The injections were administered intraspinally (IS). Motor improvement was assessed via BBB test one day before SCI and continued up to 12 weeks afterwards in all groups.
The current study revealed that a considerable percentage of the cells were BMSCs after the fourth passage. These cells were then transformed into neurospheres and NSCs. In all the experimental cell-therapy groups, a significant motor improvement was observed in comparison with that in the control group. This healing was more obvious during the period between the 2nd and the 4th weeks and less prominent during the period between the 4th and the 12th weeks.
Transplantation of NSCs leads to partial motor improvement in contusive rat models.

Recent studies have shown the key roles of different sequences and motifs in the extracellular matrix guidance. Biological activities of the macromolecules can be mimicked by the motifs of extracellular matrix. Laminin peptide sequences and motifs can bind the biomaterials of scaffolds, improve the cells mechanical protection, increase the cells growth, and lead to the formation of tissues.
Neural stem cells (NSCs) were isolated from embryonic ganglionic eminences of 14 days rats and cultured as neurosphere. The number and diameter of neurospheres on days 3, 7, and 10 were measured. NSCs were cultured by two-dimensional (2D) and 3D cultures. To evaluate cell survival, Live/Dead kit was used on days 1 and 7. The cell proliferation was assessed using the MTS assay on days 1 and 7.
Our finding showed that the cells isolated from ganglionic eminences have a high proliferative capacity. According to the proliferation assay measurements, the number and diameter of neurosphere significantly increased after culturing for 10 days. Cell proliferation and survival in the self-assembling peptide nanofiber containing laminin motif (SAPN-LM) were significantly higher than that of 2D.
SAPN-LM improved cell proliferation and survival and suggest an appropriate models for further investigations.

Stem cells are characterized by two fundamental properties; self-renewal and differentiation. Self-renewal is an integration of proliferation control with the maintenance of an undifferentiated state. Self-renewal trait is regulated by a dynamic process between transcription factors, epigenetic control, microRNA regulators, and cell-extrinsic signals from the niche of stem cells. The other feature of stem cells is the capability of differentiation to various cell types. Neural stem cells are able to differentiate to neuron, glial cell, and oligodendrocyte. The process of oligodendrocyte differentiation also is regulated by an interaction between the genetic and epigenetic programs. Recent studies reveal the key role of histone modifications in epigenetic regulation of gene expression during oligodendrocyte development. Moreover, retinoic acid pathway has been shown in stem cell differentiation toward neurons.
Detection of signaling cascades and regulatory networks of self-renewal and differentiation of neural stem cells improve new therapeutic methods for neural diseases, such as brain injuries and brain tumors as well as neurodegenerative diseases, like Huntington, Alzheimer, Parkinson, and demyelination diseases, such as multiple sclerosis. Moreover, understanding of these pathways leads to specific and stable differentiation of neural stem cells toward functional oligodendrocyte for alternative therapy.

Alzheimer's disease (AD) is the most common neurodegenerative disorder with the prevalence of one eighth or about 10% of people older than 65 years old. Aiming to induce progressive dementia and neurodegeneration, intracerebroventricularly (ICV) injection of streptozocin (STZ), a diabetogenic factor, was performed. Since this model leads to behavioral disorders, impaired energy, and glucose utilization, it is an appropriate model for AD. Reduction of the potency of stem cells in the subventricular zone (SVZ), one of the brain neurogenic regions, in AD has been reported. In this study, we examined the effect of ICV administration of STZ on stem cell proliferation in SVZ.
Thirty male Wistar rats were classified into three groups, including control, sham, and STZ. Drug injection (3 mg/kg- ICV) was performed in lateral ventricles in days 1 and 3 after recovery of operation. Finally, after SVZ cell culture, cell proliferation was measured by evaluation of morphology, number, and diameter indexes of neurospheres.
Our study revealed that proliferation indexes, such as diameter and the number of neurosphere, were significantly decreased in the treatment group compared to control and sham groups.
Our data has shown that application of STZ decreases proliferation of stem cells in SVZ of the brain.

One of the approaches for treatment of demylination diseases is cell therapy. Stem cells have been used as a source for generating oligodendrocyte. In a previous communication، the oligodendrocyte-like cells (OLCs) were generated from bone marrow stromal cells (BMSCs) using preinducers (dimethyl sulfoxide and retinoic acid) and induction protocol (PDGF، bFGF، heregulin and T3). In this investigation، we tried to increase the yield of oligodendrocyte-like cells (OLCs) by inducing the neural stem cells generated from neurospheres-derived BMSCs. In this research study، BMSCs of adult female rats were expanded and then induced to form neurospheres (NS) using B27، the epidermal growth factor (EGF) and the basic fibroblast growth factor (bFGF)، and subsequent isolation of neural stem cells (NSCs). This was followed by induction of the NSCs into OLCs with heregulin، PDGF-AA، bFGF and T3. BMSCs، NS، NSCs and OLCs were characterized using immunocytochemistry for fibronectin، CD44، CD90، CD45، Oct-4، O4، Oligo2، O1 and MBP markers. PDGF receptor α (PDGFR-α)، Olig2 and MOG expression were evaluated using RT-PCR. The BMSCs expressed CD44، CD90، CD106 and Oct-4; the NSCs were immunoreactive to nestin and NF68، while the OLCs were immunoreactive to O4، Oligo2 and O1. In differentiating OLCs، Olig2 and PDGFR-α mRNA was detected using RT-PCR technique. Functional OLCs were generated from BMSCs-derived NS with high yield and were able to produce myelin after co-culture by motor neurons.

Nerve tissue engineering (NTE) is one of the most promising methods for the treatment of the central nervous system (CNS) neurodegenerative diseases. The three-dimensional distribution and growth of the cells within the porous of the scaffold have a significance clinical role in the NTE field. Scaffolds used in tissue engineering, not only must have a good performance, but they should also be porous, biocompatible and biodegradable. The present work aimed to fabricate and study the morphology, biodegradability and chemical characteristics of Poly-L-Lactic-Acid (PLLA) in order to use in the neural tissue engineering. In this experimental study, PLLA nano scaffold was fabricated with an appropriate structure and morphology using Electrospinning Technique. Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) were used to determine the physico-chemical properties of the scaffold. Scaffold biodegradation was studied in Phosphate-buffered saline (PBS) for 40 days. Isolated stem and progenitor cells from subventricular zone of the adult mouse brain were cultured on the scaffold and their morphology and connection properties were characterized using SEM. SEM studies indicated that PLLA is a nano-fibrous scaffold which shows the appropriate surface characteristics. Furthermore, this nanoscaffold showed a high degradation and water uptake rate in the degradation test. Finally, SEM studies confirmed the attachment and growth of the mouse neural stem and progenitor cells on the scaffold. These results suggested that the PLLA nano scaffold is an appropriate structure for the growth and differentiation of the neural stem and progenitor cells and the electrospining technique is an efficient method for the scaffold producing used in the nerve tissue engineering.

After primary brain injury, secondary mechanisms are activated and lead to releasing of various supportive and neurotrophic factors in injured tissues. The effect of the new environment on neurogenesis, proliferation, and survival of stem cells needs more investigations. The aim of the present study was to evaluate the effect of injured brain extract on proliferation of embryonic rat neural stem cells (NSCs).
NSCs were isolated from ganglionic eminences of embryonic rat then cultured as neurospheres. Next, cells were seeded in PuraMatrix scaffold as 3-dimension culture. Based on the medium content, cells were divided into 4 groups: with growth factor, without growth factor, without growth factor intact brain extract, and without growth factor injured brain extract. Proliferation assay was done by evaluation of the DiI labeled cells and the survival assay was carried out by MTS test 10 days later. For preparation of the injured brain extract, a rat brain injury model was utilized and the extract was collected 48 hours after brain injury.
The results showed that NSCs derived ganglionic eminence of embryonic rat had high proliferation ability. DiI-positive cells and MTS test showed a higher tendency of the proliferation and survival of NSCs in the without growth factor injured brain extract and growth factor groups compared to the without growth factor and without growth factor intact brain extract groups.
Our results indicated a possible positive impact of injured brain extract on survival and proliferation of rat embryonic neural stem cells. Further studies are needed to investigate our preliminary findings in details.

Neural stem cells can difrentiate to mature neural cells. Neural stem cells can migrate and repair the damage neural tissue. This study was done to determine the effect of hydro-ethanolic extract of Chamaemelum nobile on cell prolifration and apoptosis of rat hipocample neural stem cells in the oxitative stress condition. In this experimental study, neural stem cells were isolated from hippocampus of neonatal rat brain. Isolated neural stem cells were treated at 200, 400, 600, 800 and 1000 µg/ml of hydro-ethanolic extract of Chamaemelum nobile for 48h. Cells proliferation rate were evaluated by MTT assay. Anti-apoptotic property of hydro-ethanolic extract of Chamaemelum nobile evaluated using TUNEL assay method. Proliferation of neural stem cells were significantly increased in Chamaemelum nobile extract group in comparision with control (P<0.05). The rate of apoptotic cells were significantly reduced in Chamaemelum nobile extract group compared to control (P<0.05). The hydrethanolic extract of Chamaemelum nobile increases proliferation rate and reduces apoptosis of neural stem cells in the oxitative stress condition.

Cell therapies have attracted attention as treatments for central nervous system disorders. However, such research has been severely limited by poor cell survival. Cell carriers improve transplanted cell viability by providing protection following transplantation. Polyethylene glycol (PEG) hydrogels are ideal candidates for this purpose. In this study the survival rate and neural differentiation of neural stem cells (NSCs) derived bone marrow stromal cells (BMSCs) were evaluated on PEG hydrogel. BMSCs were isolated from adult rats, passaged and cultured in MDEM/F12 containing B27, EGF and bFGF to generated NSCs, which were harvested to produce NSCs. Subsequently, NSCs encapsulated in 3D PEG hydrogel and cultured for 7 days. Here, we attempted to use live/dead assay kit for assessment of cell viability and differentiation was assessed by immunocytochemical analyses of neural marker expression. The results showed that NF68, NF160 and NF200 are highly expressed in NSCs after 7 days culture in 3D PEG hydrogel differentiation medium and viabilty of NSCs was about 98.24%, but GFAP and Nestin were highly expressed in 2D culture medium and viability of NSCs was about 71.70%. These findings suggest the importance of strategies to control the chemical microenvironment surrounding cells in three-dimensional biomaterials that are being designed as cell culture platforms.

The use of an appropriate stimulus to speed up in vitro and in vivo stem cell proliferation and growth is the one of the most important issues in cell therapy. The aim of this study was in vitro evaluation of hydroethanolic extraction of citrus aurantium on proliferation and growth rates of neonate rat neural stem cells. Neural stem cells were isolated using enzymatic digestion from hippocampus region of 3 day old neonatal rat brain. To determine optimal concentration of citrus aurantium extraction, isolated neural stem cells were treated at 200, 400, 600, 800 and 1000 µg/ml for 48 h. Then cells proliferation rate were evaluated using MTT assay method. Citrus aurantium promoted neural stem cells proliferation compared to untreated cells. As well as the effect of aurantium extract is dose dependent. The result of this study showed that proliferative rate in treated cells with 600 µg/ml of Citrus aurantium extraction (0.81±0.06) significantly is higher than control (untreated neural stem cells) group (0.59±0.02). (p<0.05) Regarding the effect of Citrus aurantium extract on the proliferation rate of neural stem cells, the use of hydroethanolic extraction of Citrus aurantium can be useful for clinical purposes to cell replacement therapy of various neurodegenerative disorders such as spinal cord injury.

Despite major progress in pharmacological and surgical approaches, spinal cord injury remains a complex medical challenge. Cell replacement therapy is one of the new approaches for spinal cord injury treatment. In this study, bioactive substance TNT (a new supplement) was utilized for induction of bone marrow stromal cells (BMSCs) into neural stem cells (NSCs).
The BMSCs were extracted and cultured from the femurs and tibias of adult female wistar rats. After 3 or 4 passages, these cells were preinduced into neurospheres by TNT and neural induction supplement. Then neurospheres were induced into NSCs with B27 and TNT. The NSCs were evaluated with nestin, NF68 and SOX2.
The outcomes indicated that BMSCs were immunoreactive to CD106 (95.7 ± 0.76), OCT4 (96.2 ± 1.3) and CD45 (0.4 ± 1.2). The optimal dose and time for application of TNT were 1 M and 6 days, respectively. Differentiated cells were able to express nestin and NF68.
TNT as a non-toxic substance may be a good alternative for cell induction into NSCs for treatment of neurodegenerative disorders.

The effect of various agents on neural stem cells differentiation, because of their ability to use in neurodegenerative diseases, has been widely considered. In this study, the effect of selegiline on mouse neural stem cells differentiation was evaluated. Neural stem cells were isolated from the subventricular zone of the brain of male C57 mice (2-3 months of age). To assay the effect of selegiline on neural stem cells differentiation into neurons, astrocytes and oligodendrocytes, immunocytochemical techniques were utilized. Neural stem cells were exposed to different concentrations of selegiline (nano to micro Molar) for 7 days. Subsequently, samples were exposed to specific antibodies against neurons (β tubulin), astrocytes (Glial fibrillary acidic protein or GFAP) and oligodendrocytes (Oligodendrocyte-specific protein or OSP). The differentiated cells were counted and reported as percent of total cells. Selegiline increased the β tubulin positive cells (0.001 to 0.1 μM) and decreased the GFAP positive cells (1 μM) compared to vehicle treated neural stem cells. We found that selegiline increased the differentiation of neural stem cells into neurons. Therefore, selegiline may be a reasonable choice to use in preparation of neural stem cells for transplantation.

Adipose derived stem cells (ADSCs) have the potency to differentiate into the neuron and glial cells. One of the ways to make a large number of neural stem/progenitor cells (NS/PCs) from ADSCs is the usage of neurosphere cultivation. In this procedure, ADSCs proliferate under certain conditions continuously and make multipotent undifferentiated colonies named neurosphere that can differentiate to NS/PCs.
in the current study, adipose stem cells isolated from rat inguinal and pararenal regions. Then these cells differentiated to the NS/PCs using indirect differentiation method (neurosphere culture). Adipose derived stem cells, neurosphere and NS/PCs were evaluated using immunocytochemistry and RT-PCR techniques.
the results indicated ADSCs were immunoreactive to CD90, CD29, CD49d, CD44, CD105 and CD99 without any immunoreactivity for CD106 and CD31. In addition, these cells expressed the genes of Nanog, Oct4 and Sox2. Both of Neurosphere and NS/PCs were immunoreactive to Nestin, NF-68 and NF-200 and also were able to express Nanog, Sox2, NeuroD1, Oct4, Musashi1 and Nestin genes. However, these cells were unable to express MBP gene.
It seems that indirect differentiation is effective for differentiate ADSCs into NS/PCs.