Stem cell transplantation for treatment of cerebral ischemia in rats Effects of human umbilical cord blood stem cells and human neural stem cells

BACKGROUND： Exogenous neural stem cell transplantation promotes neural regeneration. However, various types of stem cells transplantation outcomes remain controversial. OBJECTIVE： To explore distribution, proliferation and differentiation of human neural stem cells （hNSCs） and human umbilical cord blood stem cells （hUCBSCs） following transplantation in ischemic brain tissue of rats, and to compare therapeutic outcomes between hNSCs and hUCBSCs. DESIGN, TIME AND SETTING： Randomized controlled animal studies were performed at the Experimental Animal Center of Nanjing Medical University and Central Laboratory of Second Affiliated Hospital of Nanjing Medical University of China from September 2008 to April 2009. MATERIALS： hNSCs were harvested from brain tissue of 10 13 week old fetuses following spontaneous abortion, and hUCBSCs were collected from umbilical cord blood of full-term newborns at the Second Affiliated Hospital of Nanjing Medical University of China. hNSCs and hUCBSCs were labeled by 5-bromodeoxyuridine （BrdU） prior to transplantation. METHODS： Rat models of cerebral ischemia were established by the suture method. A total of 60 healthy male Sprague Dawley rats aged 7-9 weeks were randomly assigned to hNSC transplantation, hUCBSC transplantation and control groups. The rat models in the hNSC transplantation, hUCBSC transplantation and control groups were infused with hNSC suspension, hUCBSC suspension and saline via the caudal vein, respectively. MAIN OUTCOME MEASURES： The distribution, proliferation and differentiation of hNSCs and hUCBSCs in ischemic brain tissue were observed using immunohistochemical methods. Neurological function in rats was assessed using the neurological severity score. RESULTS： The number of BrdU-positive cells was significantly greater in the hNSC transplantation group compared with hUCBSC transplantation group at 14 days following transplantation （P 〈 0.05） The number of BrdU-positive cells reached a peak at 28 days following transplantation. Nestin-positive, glial fibrillary acidic protein-positive, cyclic nucleotide 3＇ phosphohydrolase-positive and neuron specific enolase-positive cells were visible following transplantation. No significant difference was determined in the constituent ratio of various cells between hNSC and hUCBSC transplantation groups （P 〉 0.05）. The neurological severity score was significantly decreased in rats at 21 days following transplantation （P 〈 0.05）. No significant difference was detected in neurological severity score between hNSC and hUCBSC transplantation groups at various time points （P 〉 0.05）. CONCLUSION： The transplanted hNSCs and hUCBSCs can migrate into ischemic brain tissue, proliferate and differentiate into neuron-like, astrocyte-like and oligodendrocyte-like cells, and improve neurological function in rats with cerebral ischemia.

Maintaining moderate levels of hypochlorous acid promotes neural stem cell proliferation and differentiation in the recovery phase of stroke

It has been shown clinically that continuous removal of ischemia/reperfusion-induced reactive oxygen species is not conducive to the recovery of late stroke.Indeed,previous studies have shown that excessive increases in hypochlorous acid after stroke can cause severe damage to brain tissue.Our previous studies have found that a small amount of hypochlorous acid still exists in the later stage of stroke,but its specific role and mechanism are currently unclear.To simulate stroke in vivo,a middle cerebral artery occlusion rat model was established,with an oxygen-glucose deprivation/reoxygenation model established in vitro to mimic stroke.We found that in the early stage(within 24 hours)of ischemic stroke,neutrophils produced a large amount of hypochlorous acid,while in the recovery phase(10 days after stroke),microglia were activated and produced a small amount of hypochlorous acid.Further,in acute stroke in rats,hypochlorous acid production was prevented using a hypochlorous acid scavenger,taurine,or myeloperoxidase inhibitor,4-aminobenzoic acid hydrazide.Our results showed that high levels of hypochlorous acid(200μM)induced neuronal apoptosis after oxygen/glucose deprivation/reoxygenation.However,in the recovery phase of the middle cerebral artery occlusion model,a moderate level of hypochlorous acid promoted the proliferation and differentiation of neural stem cells into neurons and astrocytes.This suggests that hypochlorous acid plays different roles at different phases of cerebral ischemia/reperfusion injury.Lower levels of hypochlorous acid(5 and 100μM)promoted nuclear translocation ofβ-catenin.By transfection of single-site mutation plasmids,we found that hypochlorous acid induced chlorination of theβ-catenin tyrosine 30 residue,which promoted nuclear translocation.Altogether,our study indicates that maintaining low levels of hypochlorous acid plays a key role in the recovery of neurological function.

Exogenous neural stem cell transplantation for cerebral ischemia

Cerebral ischemic injury is the main manifestation of stroke,and its incidence in stroke patients is 70–80%.Although ischemic stroke can be treated with tissue-type plasminogen activator,its time window of effectiveness is narrow.Therefore,the incidence of paralysis,hypoesthesia,aphasia,dysphagia,and cognitive impairment caused by cerebral ischemia is high.Nerve tissue regeneration can promote the recovery of the aforementioned dysfunction.Neural stem cells can participate in the reconstruction of the damaged nervous system and promote the recovery of nervous function during self-repair of damaged brain tissue.Neural stem cell transplantation for ischemic stroke has been a hot topic for more than 10 years.This review discusses the treatment of ischemic stroke with neural stem cells,as well as the mechanisms of their involvement in stroke treatment.

Neural stem cell transplantation in the hippocampus of rats with cerebral ischemia/reperfusion injury Activation of the phosphatidylinositol-3 kinase/Akt pathway and increased brain-derived neurotrophic factor expression

The phosphatidylinositol-3 kinase （PI3K）/Akt pathway and brain-derived neurotrophic factor （BDNF） are involved in neurological functional recovery following cerebral ischemia. Therefore, we hypothesized that mechanisms of neuroprotection by transplantation of neural stem cells （NSCs） on cerebral ischemia contributed to activation of the PI3K/Akt pathway and enhanced BDNF expression. In the present study, Wortmannin （a specific, covalent inhibitor of PI3K） was administered adjacent to ischemic hippocampus by stereotactic transplantation to further confirm the neuroprotective mechanisms of NSC transplantation following cerebral ischemia. Results showed that focal infarct volume was significantly smaller in the NSCs group, but the neurological behavior score in the NSC group was significantly greater than the middle cerebral artery occlusion model group, Wortmannin treatment group, and NSCs ＋ Wortmannin treatment group. Protein expression of BDNF was significantly greater in the NSC group compared with the Wortmannin treatment group and NSCs ＋ Wortmannin treatment group. These results suggest that the neuroprotective role of NSC transplantation in the cerebral ischemia activated the PI3K/Akt pathway and upregulated BDNF expression in lesioned brains.

Radix Ilicis Pubescentis total flavonoids combined with mobilization of bone marrow stem cells to protect against cerebral ischemia/reperfusion injury

Previous studies have shown that Radix Ilicis Pubescentis total flavonoids have a neuroprotective effect, but it remains unclear whether Radix Ilicis Pubescentis total flavonoids have a synergistic effect with the recombinant human granulocyte colony stimulating factor-mobilized bone marrow stem cell transplantation on cerebral ischemia/reperfusion injury. Rat ischemia models were administered 0.3, 0.15 and 0.075 g/kg Radix Ilicis Pubescentis total flavonoids from 3 days before modeling to 2 days after injury. Results showed that Radix Ilicis Pubescentis total flavonoids could reduce pathological injury in rats with cerebral ischemia/reperfusion injury. The number of Nissl bodies increased, Bax protein expression decreased, Bcl-2 protein expression increased and the number of CD34-positive cells increased. Therefore, Radix Ilicis Pubescentis total flavonoids can improve the bone marrow stem cell mobilization effect, enhance the anti-apoptotic ability of nerve cells, and have a neuroprotective effect on cerebral ischemia/reperfusion injury in rats.

Ultra-early treatment of bone marrow-derived mesenchymal stem cells for focal cerebral ischemia/ reperfusion injury

The time point at which bone marrow-derived mesenchymal stem cells（BMSCs）can be used in transplantation for the treatment of ischemic brain injury remains unclear.In the present study,BMSCs were transplanted to the ischemic site 90 minutes post-ischemia.The results demonstrated that the transplanted BMSCs improved neurological function,reduced infarct volume,increased survivin expression,decreased caspase-3 expression and reduced apoptosis.This suggests that BMSCs transplanted at an ultra-early stage ameliorated brain ischemia by increasing survivin expression,decreasing caspase-3 expression and reducing apoptosis at the ischemia/reperfusion injury site.

Ischemic accumulation of succinate induces Cdc42 succinylation and inhibits neural stem cell proliferation after cerebral ischemia/reperfusion

Ischemic accumulation of succinate causes cerebral damage by excess production of reactive oxygen species. However, it is unknown whether ischemic accumulation of succinate affects neural stem cell proliferation. In this study, we established a rat model of cerebral ischemia/reperfusion injury by occlusion of the middle cerebral artery. We found that succinate levels increased in serum and brain tissue(cortex and hippocampus) after ischemia/reperfusion injury. Oxygen-glucose deprivation and reoxygenation stimulated primary neural stem cells to produce abundant succinate. Succinate can be converted into diethyl succinate in cells. Exogenous diethyl succinate inhibited the proliferation of mouse-derived C17.2 neural stem cells and increased the infarct volume in the rat model of cerebral ischemia/reperfusion injury. Exogenous diethyl succinate also increased the succinylation of the Rho family GTPase Cdc42 but repressed Cdc42 GTPase activity in C17.2 cells. Increasing Cdc42 succinylation by knockdown of the desuccinylase Sirt5 also inhibited Cdc42 GTPase activity in C17.2 cells. Our findings suggest that ischemic accumulation of succinate decreases Cdc42 GTPase activity by induction of Cdc42 succinylation, which inhibits the proliferation of neural stem cells and aggravates cerebral ischemia/reperfusion injury.

Neuronal differentiation of adipose-derived stem cells and their transplantation for cerebral ischemia

OBJECTIVE： To review published data on the biological characteristics, differentiation and applications of adipose-derived stem cells in ischemic diseases. DATA RETRIEVAL： A computer-based online search of reports published from January 2005 to June 2012 related to the development of adipose-derived stem cells and their transplantation for treatment of cerebral ischemia was performed in Web of Science using the key words ＂adipose-derived stem cells＂, ＂neural-like cells＂, ＂transplantation＂, ＂stroke＂, and ＂cerebral ischemia＂. SELECTION CRITERIA： The documents associated with the development of adipose-derived stem cells and their transplantation for treatment of cerebral ischemia were selected, and those published in the last 3-5 years or in authoritative journals were preferred in the same field. Totally 89 articles were obtained in the initial retrieval, of which 53 were chosen based on the inclusion criteria. MAIN OUTCOME MEASURES： Biological characteristics and induced differentiation of adipose-derived stem cells and cell transplantation for disease treatment as well as the underlying mechanism of clinical application. RESULTS： The advantages of adipose-derived stem cells include their ease of procurement, wide availability, rapid expansion, low tumorigenesis, low immunogenicity, and absence of ethical constraints. Preclinical experiments have demonstrated that transplanted adipose-derived stem cells can improve neurological functions, reduce small regions of cerebral infarction, promote angiogenesis, and express neuron-specific markers. The improvement of neurological functions was demonstrated in experiments using different methods and time courses of adipose-derived stem cell transplantation, but the mechanisms remain unclear. CONCLUSION： Further research into the treatment of ischemic disease by adipose-derived stem cell transplantation is needed to determine their mechanism of action.

Effects of Electroacupuncture Combined with Repetitive Transcranial Magnetic Stimulation on the Expression of Nestin in Neural Stem Cell after Focal Cerebral Ischemia in Adult Rats

Objective:To investigate the influence of electroacupuncture(EA) combined with repetitive transcranial magnetic stimulation(rTMS) on the temporal profile of nestin expression after induction of focal cerebral ischemia in adult rats and to explore the mechanism of EA combined with rTMS in treating ischemic brain injury.Method:The model of transient focal ischemia was produced by occlusion of middle cerebral artery.Seventy-five Wistar rats were randomly divided into normal group,model group,EA group,rTMS group and EA +rTMS group.The neurologic impairment rating and ability of learning and memory were observed at the 7th、14th and 28th d after infarction respectively.Meanwhile,Western blotting was used to observe the number of nestin expression positive cells.Result:Nestin-positive cells were found in cortex,subgranular zone(SGZ),subventricular zone(SVZ) of the ipsilateral side at different time points after cerebral ischemia.The number of nestin-positive cells peaked at the 7th d,began to decrease at the 14th d and was significantly higher in EA+rTMS group than that in model group(P< 0.05),then almost reached normal at the 28th d.The improvement of neural motor function deficits as well as the indexes of learning and memory were more obvious in EA+rTMS group compared with model group(P<0.01,P<0.05).These effects were most obvious in EA +rTMS group compared with the EA and rTMS group(P<0.05).Conclusion:EA and rTMS possess the potency of building up and can increase the number of nestin-positive cells in some brain regions after focal cerebral ischemia,which might be one of the important mechanisms of EA combined with rTMS in treating ischemia brain injury.

Human neural stem cells promote proliferation of endogenous neural stem cells and enhance angiogenesis in ischemic rat brain

Transplantation of human neural stem cells into the dentate gyrus or ventricle of rodents has been reportedly to enhance neurogenesis. In this study, we examined endogenous stem cell proliferation and angiogenesis in the ischemic rat brain after the transplantation of human neural stem cells. Focal cerebral ischemia in the rat brain was induced by middle cerebral artery occlusion. Human neural stem cells were transplanted into the subventricular zone. The behavioral performance of human neural stem cells-treated ischemic rats was significantly improved and cerebral infarct volumes were reduced compared to those in untreated animals. Numerous transplanted human neural stem cells were alive and preferentially localized to the ipsilateral ischemic hemisphere. Furthermore, 5-bromo-2′-deoxyuridine-labeled endogenous neural stem cells were observed in the subventricular zone and hippocampus, where they differentiated into cells immunoreactive for the neural markers doublecortin, neuronal nuclear antigen Neu N, and astrocyte marker glial fibrillary acidic protein in human neural stem cells-treated rats, but not in the untreated ischemic animals. The number of 5-bromo-2′-deoxyuridine-positive ？ anti-von Willebrand factor-positive proliferating endothelial cells was higher in the ischemic boundary zone of human neural stem cells-treated rats than in controls. Finally, transplantation of human neural stem cells in the brains of rats with focal cerebral ischemia promoted the proliferation of endogenous neural stem cells and their differentiation into mature neural-like cells, and enhanced angiogenesis. This study provides valuable insights into the effect of human neural stem cell transplantation on focal cerebral ischemia, which can be applied to the development of an effective therapy for stroke.

Characterization of astrocytes and microglial cells in the hippocampal CA1 region after transient focal cerebral ischemia in rats treated with Ilexonin A

Ilexonin A is a compound isolated from the root of Ilex pubescens,a traditional Chinese medicine.Ilexonin A has been shown to play a neuroprotective role by regulating the activation of astrocytes and microglia in the peri-infarct area after ischemia.However,the effects of ilexonin A on astrocytes and microglia in the infarct-free region of the hippocampal CA1 region remain unclear.Focal cerebral ischemia models were established by 2-hour occlusion of the middle cerebral artery in rats.Ilexonin A(20,40 or 80 mg/kg)was administered immediately after ischemia/reperfusion.The astrocyte marker glial fibrillary acidic protein,microglia marker Iba-1,neural stem cell marker nestin and inflammation markers were detected by immunohistochemistry and western blot assay.Expression levels of tumor necrosis factor-αand interleukin 1βwere determined by enzyme linked immunosorbent assay in the hippocampal CA1 tissue.Astrocytes were activated immediately in progressively increasing numbers from 1,3,to 7 days post-ischemia/reperfusion.The number of activated astrocytes further increased in the hippocampal CA1 region after treatment with ilexonin A.Microglial cells remained quiescent after ischemia/reperfusion,but became activated after treatment with ilexonin A.Ilexonin A enhanced nestin expression and reduced the expression of tumor necrosis factor-αand interleukin 1βin the hippocampus post-ischemia/reperfusion.The results of the present study suggest that ilexonin A has a neuroprotective effect in the hippocampus after ischemia/reperfusion,probably through regulating astrocytes and microglia activation,promoting neuronal stem cell proliferation and reducing the levels of pro-inflammatory factors.This study was approved by the Animal Ethics Committee of the Fujian Medical University Union Hospital,China.

Application of magnetic resonance imaging for monitoring stem cell transplantation for the treatment of cerebral ischemia

OBJECTIVE： To identify global research trends in the application of MRI for monitoring stem cell transplantation using a bibliometric analysis of Web of Science. DATA RETRIEVAL： We performed a bibliometric analysis of studies relating to the application of MRI for detecting stem cell transplantation for the treatment of cerebral ischemia using papers in Web of Science published from 2002 to 2011. SELECTION CRITERIA： The inclusion criteria were： （a） peer-reviewed articles on the application of MRI for detecting transplanted stem cells published and indexed in Web of Science; （b） year of publication between 2002 and 2011. Exclusion criteria were： （a） articles that required manual searching or telephone access; （b） some corrected papers. MAIN OUTCOME MEASURES： （1） Annual publication output; （2） distribution according to journals; （3） distribution according to institution; （4） distribution according to country; （5） top cited authors over the last 10 years. RESULTS： A total of 1 498 studies related to the application of MRI for monitoring stem cell transplantation appeared in Web of Science from 2002 to 2011, almost half of which were derived from American authors and institutes. The number of studies on the application of MRI for detecting stem cell transplantation has gradually increased over the past 10 years. Most papers on this topic appeared in Magnetic Resonance in Medicine. CONCLUSION： This analysis suggests that few experimental studies have been investigated the use of MRI for tracking SPIO-labeled human umbilical cord blood-derived mesenchymal stem cells during the treatment of cerebral ischemia.

PROLIFERATION AND MIGRATION OF EPENDYMAL CELLS IN THE BRAIN OF ADULT RATS AFTER PERMANENT FOCAL CEREBRAL ISCHEMIA

Objective Ependymal cells are thought to be the primary source of neural stem cells in the adult central nervous system. The purpose of this study is to examine spatial and temporal profiles of ependymal cell proliferation and migration after focal cerebral ischemia. Methods Eighty male Sprague Dawley rats underwent permanent middle cerebral artery occlusion after injection of 10 μL of 0.2% Dil into the lateral ventricle. Rats were sacrificed and brain sections were acquired for pathological evaluation and laser confocal imaging at day 1,3,7,11,14,21 and 28 after ischemia. Results The density of Dil-labeled cells in the ischemic ipsilateral subventricular zone was significantly higher than that in the control group and these labeled cells dispersed in the ischemic ipsilateral subventricular zone and/or were located in ependyma from day 1 to 11. In the ischemic ipsilateral cortex, some Dil-labeled cells occurred in peri-infarction and infarction of parietal region at day14 and peaked at day 21 when some Dil-labeled cell nodules were found in this region. During postischemic day 14-28, a significant decrease in labeled cell density in the ischemic ipsilateral subventricular zone was coincident with a significant increase in labeled cells density in the cortex (peri-infarction and infarction). Conclusion The results indicate that ependymal cells proliferate and migrate after focal cerebral ischemia in the adult rat brain.

Buyang Huanwu Decoction regulates neural stem cell behavior in ischemic brain

The traditional Chinese medicine Buyang Huanwu Decoction has been shown to improve the neu- rological function of patients with stroke. However, the precise mechanisms underlying its effect remain poorly understood. In this study, we established a rat model of cerebral ischemia by middle cerebral artery occlusion and intragastrically administered 5 g/kg Buyang Huanwu Decoction, once per day, for 1, 7, 14 and 28 days after cerebral ischemia. Immunohistochemical staining revealed a number of cells positive for the neural stem cell marker nestin in the cerebral cortex, the subven- tricular zone and the ipsilateral hippocampal dentate gyrus in rat models of cerebral ischemia. Buyang Huanwu Decoction significantly increased the number of cells positive for 5-bromodeoxyuridine （BrdU）, a cell proliferation-related marker, microtubule-associated protein-2, a marker of neuronal differentiation, and growth-associated protein 43, a marker of synaptic plasticity in the ischemic rat cerebral regions. The number of positive cells peaked at 14 and 28 days after intragastric administration of Buyang Huanwu Decoction. These findings suggest that Buyang Huanwu Decoction can promote the proliferation and differentiation of neural stem cells and en- hance synaptic plasticity in ischemic rat brain tissue.

Neuronal-like cell differentiation of non-adherent bone marrow cell-derived mesenchymal stem cells

Non-adherent bone marrow cell-derived mesenchymal stem cells from C57BL/6J mice were sepa- rated and cultured using the ＂pour-off＂ method. Non-adherent bone marrow cell-derived mesen- chymal stem ceils developed colony-forming unit-fibroblasts, and could be expanded by supple- mentation with epidermal growth factor. Immunocytochemistry showed that the non-adherent bone marrow cell-derived mesenchymal stem cells exposed to basic fibroblast growth factor/epidermal growth factor/nerve growth factor expressed the neuron specific markers, neurofilament-200 and NeuN, in vitro. Non-adherent bone marrow cell-derived mesenchymal stem cells from 13-galactosidase transgenic mice were also transplanted into focal ischemic brain （right corpus striatum） of C57BL/6J mice. At 8 weeks, cells positive for LacZ and 13-galactosidase staining were observed in the ischemic tissues, and cells co-labeled with both 13-galactosidase and NeuN were seen by double immunohistochemical staining. These findings suggest that the non-adherent bone marrow cell-derived mesenchymal stem cells could differentiate into neuronal-like cells in vitro and in vivo.

Effects of Salvia miltiorrhiza Bge.f.alba on neuronal regeneration following cerebral ischemia/reperfusion

BACKGROUND： Subsequent to cerebral ischemic injury, endogenous neural stem cells are activated, but ischemia-induced neuronal loss is not compensated by ischemic injury-induced neural regeneration. Salvia （S.） miltiorrhiza Bge.f.alba （Baihua Danshen, a Chinese herbal medicine） could enhance learning and memory functions, as well as promote neural regeneration. OBJECTIVE： To observe the effects of S. miltiorrhiza Bge.f.alba on recovery from cerebral ischemia-reperfusion injury, and the influence on neuronal regeneration and differentiation. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiments were performed at the Experimental Animal Center and Neurobiology Laboratory of Taishan Medical College in September of 2006. MATERIALS： S. miltiorrhiza Bge.f.alba was provided by Taishan Medical College Botanic Garden, Taian, China; dl-3n-butylphthalide （NBP） soft capsule was purchased from NBP Pharmaceutical, Shijiazhuang, China; mouse anti-bromodeoxyuridine antibody, rabbit anti-NF200 antibody, and bromodeoxyuridine were purchased from Sigma, Louis, MO, USA; Annexin V-fluorescein isothiocyanate/PI apoptosis kit was purchased from Nanjing Comissariado Biological Technology Development, Nanjing, China. METHODS： Adult Sprague Dawley rats were randomly assigned to sham surgery, model （cerebral ischemia and reperfusion, without administration）, S. miltiorrhiza Bge.f.alba, and NBP groups. Following establishment of the cerebral ischemia/reperfusion model, S. miltiorrhiza Bge.f.alba or NBP （1 mL/100 g） was respectively perfused at 30 minutes following cerebral ischemia/reperfusion. MAIN OUTCOME MEASURES： Alterations in cerebral blood flow before and after ischemia/reperfusion, NF200- and bromodeoxyuridine-double positive cells in striatum of affected tissues, as well as neuronal apoptosis rate at days 5 and 7 following cerebral ischemia/reperfusion. RESULTS： Subsequent to cerebral ischemia reperfusion, cerebral blood flow was reduced. Following treatment with S. miltiorrhiza Bge.f.alba, cerebral blood flow significantly increased （P 〈 0.05）. NBP treatment was inferior to S. miltiorrhiza Bge.f.alba with regard to stabilization of cerebral blood flow （P 〈 0.05）. S. miltiorrhiza Bge.f.alba significantly increased the number of newly formed neurons in rats following cerebral ischemia （P 〈 0.05） and significantly reduced neuronal apoptosis （P 〈 0.05）, with no significant difference compared with NBP treatment （P 〉 0.05）. CONCLUSION： S. miltiorrhiza Bge.f.alba significantly increased cerebral blood flow, reduced neuronal apoptosis, and promoted neuronal regeneration in rats with cerebral ischemia/reperfusion impairment.

Effects of Buyang Huanwu decoction on cell proliferation and differentiation in the hippocampal dentate gyrus of aged rats following cerebral ischemia/reperfusion

BACKGROUND： The mobilization of endogenous stem cells is an effective way to promote repair following ischemic brain damage. Buyang Huanwu decoction （BHD） can effectively improve cerebral blood flow and protect against cerebral ischemia/reperfusion damage. OBJECTIVE： To study the effects of BHD on cell proliferation and differentiation in the hippocampal dentate gyrus of rats following cerebral infarction, to investigate the protective effects of BHD against cerebral infarction, and to analyze the dose-effect relationship. DESIGN, TIME AND SETTING： This randomized, controlled, animal study was performed at the Laboratory of Department of Physiology, Henan College of Traditional Chinese Medicine, China from June 2007 to February 2008. MATERIALS： A total of 36 male, Sprague Dawley rats, aged 20-21 months, were equally and randomly assigned to the following groups： sham operation, model control, and nimodipine, as well as high-dose, moderate-dose, and low-dose BHD. BHD was composed of milkvetch root, Chinese angelica, red peony root, earthworm, peach seed, safflower, and Szechwan Iovage rhizome, which were provided by the Outpatient Department, Henan College of Traditional Chinese Medicine, China. METHODS： The Chinese medicinal ingredients described above were decocted. The external carotid artery was ligated in rats from the sham operation group. Rat models of focal cerebral infarction were established by middle cerebral artery occlusion in the model control and nimodipine groups, as well as the high-dose, moderate-dose, and low-dose BHD groups. The drugs were administered by gavage 5 days, as well as 2 hours, prior to model induction. Rats in the nimodipine group were daily administered a 6 mg/kg nimodipine suspension by gavage. Rats in the high-dose, moderate-dose, and low-dose BHD groups were administered daily 26, 13, and 6.5 g/kg BHD, respectively. Rats in the sham operation and model control groups were treated with an equal volume of saline. MAIN OUTCOME MEASURES： The effects of BHD on neurological dysfunction score, brain water content, cell proliferation and differentiation in the hippocampal dentate gyrus, and pathological changes in the ischemic brain hemisphere were measured in cerebral infarction rats. RESULTS： Compared with the sham operation group, the neurological dysfunction score, brain water content, number of BrdU-positive cells, BrdU/NeuN-positive cells, and BrdU/GFAP-positive cells in the hippocampal dentate gyrus significantly increased in the model control group （P 〈 0.01 ）. Compared with the model control group, neurological dysfunction score and brain water content were significantly decreased （P 〈 0.01 or 0.05）, as were the number of BrdU-positive and BrdU/NeuN-positive cells （P 〈 0.01 or 0.05）. The number of BrdU/GFAP-positive cells was significantly reduced （P 〈 0.05） in the nimodipine group, high-dose, moderate-dose, and low-dose BHD groups. Compared with the nimodipine group, the neurological dysfunction score was significantly reduced in the moderate-dose BHD group （P 〈 0.05）. However, the number of BrdU-positive cells was significantly increased in the rat hippocampal dentate gyrus in the high-dose and moderate-dose BHD groups （P 〈 0.01 or 0.05）. The following was determined by microscopy： slightly disarranged neural cells, mild vascular dilatation, inflammatory cell infiltration, and light tissue edema were observed in the nimodipine group; inflammatory celt infiltration was reduced in the low-dose BHD group; cerebral edema and inflammatory cell infiltration were significantly reduced in the high-dose and in the moderate-dose BHD group. Electron microscopy revealed lipofuscin, slightly swollen mitochondria, and normal rough endoplasmic reticulum in the high-dose and moderate-dose BHD groups. Improvement was best in the moderate-dose BHD group. CONCLUSION： Cerebral ischemia activated proliferation of neural stem cells in the rat hippocampal dentate gyrus. The actions of BHD against cerebral ischemia/reperfusion damage correlated with proliferation and differentiation of neural stem cells in the hippocampal dentate gyrus. A moderate-dose of BHD resulted in the most effective outcome.

Neural Stem Cells Transfected with Leukemia Inhibitory Factor Promote Neuroprotection in a Rat Model of Cerebral Ischemia

Leukemia inhibitory factor(LIF) contributes to the neuroprotection by neural stem cells(NSCs) after ischemic stroke. Our aim was to explore whether LIFtransfected NSCs(LIF-NSCs) can ameliorate brain injury and promote neuroprotection in a rat model of cerebral ischemia. To accomplish this goal, we transfected NSCs with a lentivirus carrying the LIF gene to stably overexpress LIF. The LIF-NSCs reduced caspase 3 activation under conditions of oxygen-glucose deprivation in vitro.Transient cerebral ischemia was induced in rats by 2 h of middle cerebral artery occlusion(MCAo), and LIF-NSCs were intravenously injected at 6 h post-ischemia. LIF-NSC treatment reduced the infarction volume and improved neurological recovery. Moreover, LIF-NSCs improved glial cell regeneration and ameliorated white matter injuryin the MCAo rats. The NSCs acted as carriers and increased the expression of LIF in the lesions to protect against cerebral infarction, suggesting that LIF-NSCs could be a potential treatment for cerebral infarction.

神经干细胞源性外泌体对脑缺血再灌注损伤后大鼠氧化应激和细胞凋亡的影响

目的探讨神经干细胞源性外泌体(NSC-Exos)对脑缺血再灌注损伤(MCAO)模型大鼠氧化应激和神经细胞凋亡的影响。方法135只雄性SD大鼠随机分为Sham组(手术、不缺血、不微量注射)、MCAO组(手术、缺血、不微量注射)及NSC-Exos组(手术、缺血、侧脑室微量注射),于微量注射后大鼠脑缺血再灌注第1、7及14天时行神经功能缺陷评分,2,3,5-三苯基氯化四氮唑(TTC)检测脑组织相对梗死体积,HE染色和透射电子显微镜观察海马CA3区神经细胞形态及亚显微结构,比色法检测海马组织匀浆中谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)和丙二醛(MDA)的含量,Western blot检测海马组织中Bcl-2、Bax蛋白的表达。结果与Sham组相比,MCAO组大鼠神经功能缺陷评分增高(P<0.05),脑组织相对梗死体积显著增大(P<0.05),神经细胞形态及超微结构受损严重,海马组织匀浆中GSH-PX、SOD酶活性降低,MAD含量增高(P<0.05),Bcl-2含量降低、Bax蛋白含量增加(P<0.05);与MCAO组相比,NSC-Exos组大鼠神经功能缺陷评分降低(P<0.05),脑组织相对梗死体积减小(P<0.05),存活神经细胞形态较为完好,超微结构较为清晰,海马组织匀浆中GSH-PX、SOD酶活性均增高,MAD含量减小(P<0.05),Bcl-2蛋白随缺血再灌注时间的延长表达增高,蛋白Bax表达减少(P<0.05)。结论NSC-Exos可改善MCAO大鼠的神经功能,减轻神经元的病理损伤,其机理可能与抑制海马组织的氧化应激和细胞凋亡有关。

从Notch通路探讨电针促进局灶性脑缺血再灌注大鼠海马神经干细胞增殖的作用机制

目的:通过Notch信号通路探讨电针对局灶性脑缺血再灌注模型大鼠海马神经干细胞增殖的促进作用,阐明其治疗脑梗死的可能机制。方法:将54只SD大鼠随机分为假手术组、模型组及电针组,以大脑中动脉闭塞(MCAO)法建立大鼠局灶性脑缺血再灌注模型,通过巢蛋白(nestin)免疫组化法观察脑缺血大鼠海马神经干细胞增殖情况,应用蛋白免疫印迹法(Western blot)和RT-PCR检测海马组织中Notch信号通路上关键信号分子Notch1和胞内片段(NICD)的表达情况,同时使用酶联免疫吸附法(ELISA)测定大鼠血清中血管内皮生长因子(VEGF)浓度。结果:电针"曲池"、"足三里"穴可明显改善MCAO大鼠的神经功能缺损症状;促进脑缺血后海马神经干细胞(nestin+)的增殖(模型组vs电针组:173.40±38.76 vs 246.80±47.73,P=0.028);增强Notch信号通路中Notch1和NICD的表达,并提高血清中VEGF的分泌。结论:电针可通过活化Notch信号通路,同时促进VEGF的分泌,促进海马神经干细胞的增殖,来实现对脑缺血的治疗作用。