Bone marrow mesenchymal stem cells transplantation promotes the release of endogenous erythropoietin after ischemic stroke

This study investigated whether bone marrow mesenchymal stem cell(BMSC) transplantation protected ischemic cerebral injury by stimulating endogenous erythropoietin. The model of ischemic stroke was established in rats through transient middle cerebral artery occlusion. Twenty-four hours later, 1 × 106 human BMSCs(h BMSCs) were injected into the tail vein. Fourteen days later, we found that h BMSCs promoted the release of endogenous erythropoietin in the ischemic region of rats. Simultaneously, 3 μg/d soluble erythropoietin receptor(s EPOR) was injected into the lateral ventricle, and on the next 13 consecutive days. s EPOR blocked the release of endogenous erythropoietin. The neurogenesis in the subventricular zone was less in the h BMSCs + s EPOR group than in the h BMSCs + heat-denatured s EPOR group. The adhesive-removal test result and the modified Neurological Severity Scores(m NSS) were lower in the h BMSCs + s EPOR group than in the heat-denatured s EPOR group. The adhesive-removal test result and m NSS were similar between the h BMSCs + heat-denatured s EPOR group and the h BMSCs + s EPOR group. These findings confirm that BMSCs contribute to neurogenesis and improve neurological function by promoting the release of endogenous erythropoietin following ischemic stroke.     

Therapeutic effects of lipo-prostaglandin E1 on angiogenesis and neurogenesis after ischemic stroke in rats

Previous studies have demonstrated that prostaglandin E1 (PGE1) has a neuroprotective effect on cerebral ischemia. However, it remains unknown whether PGE1 promotes angiogenesis and neurogenesis after ischemic stroke. In this study, adult male Sprague-Dawley rats were subjected to permanently distal middle cerebral artery occlusion (MCAO). Rats were treated with lipo-prostaglandin E1(lipo-PGE1, 10 μg/kg/d) or the same volume of 0.9% saline starting 24 hours after MCAO daily for 6 consecutive days. All rats were injected 5'-bromo-2'-deoxyuridine (BrdU, 50 mg/kg) intraperitoneally every 12 hours for 3 consecutive days before being sacrificed. At 7 and 14 days after MCAO or sham-operation, rats were sacrificed. Post-stroke neurological outcome, infarction volume, angiogenesis and neurogenesis were evaluated. Treatment with lipo-PGE1 significantly increased the vascular density in the peri-infarct areas at 7 and 14 days after MCAO. The lipo-PGE1 treatment significantly enhanced the proliferation and migration of endogenous neural stem cells in the ipsilateral subventricular zone. The neural stem cells associated with blood vessels closely within a neurovascular niche in lipo-PGE1-treated rats after stroke. The lipo-PGE1 treatment also significantly improved the neurological recovery after MCAO. These results indicate that treatment with lipo-PGE1 promotes post-stroke angiogenesis, neurogenesis and their interaction, which would contribute to neurological recovery after cerebral infarction. Our study provides novel experimental evidences for the neuroprotective roles of PGE1 in ischemic stroke.     

骨髓基质细胞静脉移植治疗大鼠短暂性局灶性脑缺血

目的探讨骨髓基质细胞静脉移植治疗大鼠短暂性局灶性脑缺血的可行性及其机制。方法将大鼠骨髓基质细胞在体外纯化、扩增并经BrdU标记后,经尾静脉移植到局灶性脑缺血大鼠体内,通过神经缺损评分观察移植后大鼠神经行为学改善情况,通过组织学方法观察移植到脑内的骨髓基质细胞表达脑源性神经营养因子、缺血灶周围细胞凋亡及脑微血管密度的变化。结果骨髓基质细胞移植组大鼠的神经缺损评分显著低于对照组(P<0.05);移植到脑内的骨髓基质细胞主要选择性分布于缺血灶周围区域并表达BDNF;骨髓基质细胞移植组大鼠梗死灶周围的凋亡细胞明显少于对照组(P<0.01)、微血管密度显著高于对照组(P<0.001)。结论经静脉注射移植骨髓基质细胞能够明显促进局灶性脑缺血大鼠的神经行为功能恢复;抗凋亡及促微血管增生可能是骨髓基质细胞移植治疗局灶性脑缺血的机制之一。     

Transplantation of human mesenchymal stem cells promotes functional improvement and increased expression of neurotrophic factors in a rat focal cerebral ischemia model

Previous studies have suggested that intravenous transplantation of mesenchymal stem cells (MSCs) in rat ischemia models reduces ischemia‐induced brain damage. Here, we analyzed the expression of neurotrophic factors in transplanted human MSCs and host brain tissue in rat middle cerebral artery occlusion (MCAO) ischemia model. At 1 day after transient MCAO, 3 × 10⁶ immortalized human MSC line (B10) cells or PBS was intravenously transplanted. Behavioral tests, infarction volume, and B10 cell migration were investigated at 1, 3, 7, and 14 days after MCAO. The expression of endogenous (rat origin) and exogenous (human origin) neurotorphic factors and cytokines was evaluated by quantitative real‐time RT‐PCR and Western blot analysis. Compared with PBS controls, rats receiving MSC transplantation showed improved functional recovery and reduced brain infarction volume at 7 and 14 days after MCAO. In MSC‐transplanted brain, among many neurotrofic factors, only human insulin‐like growth factor 1 (IGF‐1) was detected in the core and ischemic border zone at 3 days after MCAO, whereas host cells expressed markedly higher neurotrophic factors (rat origin) than control rats, especially vascular endothelial growth factor (VEGF) at 3 days and epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) at 7 days after MCAO. Intravenously transplanted human MSCs induced functional improvement, reduced infarct volume, and neuroprotection in ischemic rats, possibly by providing IGF‐1 and inducing VEGF, EGF, and bFGF neurotrophic factors in host brain. © 2009 Wiley‐Liss, Inc.     

Protective role of COMP‐Ang1 in ischemic rat brain

In cerebral ischemia, the induction of angiogenesis may represent a natural defense mechanism that enables the hypoxic brain to avoid progression into infarction. Angiopoietin‐1 (Ang1) is known to produce non‐leaky and stable blood vessel formation mainly by the Tie2 receptor. Therefore, we envisioned that the application of cartilage oligomeric matrix protein‐Ang1 (COMP‐Ang1), a soluble, stable, and potent form of Ang1, would promote angiogenesis and provide a protective effect following unilateral middle cerebral artery occlusion (MCAO) in rats. To this end, we employed a 2‐hour‐MCAO model, and treated rats with adenovirus encoding COMP‐Ang1 (Ade‐COMP‐Ang1) or control virus encoding β‐gal (Ade‐β‐gal). Time course magnetic resonance images (MRIs) revealed significantly reduced infarct volume in the rats treated with Ade‐COMP‐Ang1 with an improvement of post‐ischemic neurological deficits compared with rats treated with Ade‐β‐gal. Moreover, compared to the rats treated with Ade‐β‐gal, the rats treated with Ade‐COMP‐Ang1 showed an increase in blood vessels, especially in the border zone adjacent to the infarction, increased number of endogenous neuronal progenitor cells in the ischemic brain, and decreased number of TUNEL‐positive cells. Taken together, COMP‐Ang1 reduced infarct volume and consequently attenuated post‐ischemic neurological deficits through enhanced angiogenesis and increased viable cell mass of neuronal cells. © 2009 Wiley‐Liss, Inc.     

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.     

人脐血间充质干细胞静脉移植治疗大鼠局灶性脑缺血的实验研究

目的 探讨来源于人脐血的间充质干细胞经静脉移植治疗大鼠局灶性脑缺血的可行性及其机制.方法 将人脐血间充质干细胞在体外纯化、扩增并经BrdU标记后,经尾静脉移植到局灶性脑缺血大鼠体内,通过神经缺损评分观察移植后大鼠神经行为学改善情况,通过组织学方法观察移植到脑内的人脐血间充质干细胞表达脑源性神经营养因子和缺血灶周围微血管密度变化的情况.结果 人脐血间充质干细胞移植组大鼠的神经缺损评分显著低于对照组(P＜0.05);移植到脑内的人脐血间充质干细胞主要选择性分布于缺血灶周围区域并表达脑源性神经营养因子,移植组大鼠梗死灶周围的微血管密度显著高于对照组(P＜0.01).结论 经静脉注射移植人脐血间充质干细胞能明显促进局灶性脑缺血大鼠的神经行为功能恢复,促进缺血灶周边区微血管增生可能是人脐血间充质干细胞移植治疗局灶性脑缺血的机制之一.     

Improvement of functional recovery by chronic metformin treatment is associated with enhanced alternative activation of microglia/macrophages and increased angiogenesis and neurogenesis following experimental stroke

Acute AMPK activation exacerbates ischemic brain damage experimentally. Paradoxically, the clinical use of an AMPK activator metformin reduces the incidence of stroke. We investigated whether post-stroke chronic metformin treatment promotes functional recovery and tissue repair via an M2-polarization mechanism following experimental stroke. Mice were randomly divided to receive metformin or vehicle daily beginning at 24 h after middle cerebral artery occlusion (MCAO). Neurological deficits were monitored for 30 days following MCAO. To characterize the polarization of the microglia and infiltrating macrophages, the expression of the M1 and M2 signature genes was analyzed with qPCR, ELISA and immunohistochemistry. Post-MCAO angiogenesis and neurogenesis were examined immunohistochemically. An in vitro angiogenesis model was employed to examine whether metformin promoted angiogenesis in a M2 polarization-dependent manner. Post-stroke chronic metformin treatment had no impact on acute infarction but enhanced cerebral AMPK activation, promoted functional recovery and skewed the microglia/macrophages toward an M2 phenotype following MCAO. Metformin also significantly increased angiogenesis and neurogenesis in the ischemic brain. Consistently, metformin-induced M2 polarization of BV2 microglial cells depended on AMPK activation in vitro. Furthermore, treatment of brain endothelial cells with conditioned media collected from metformin-polarized BV2 cells promoted angiogenesis in vitro. In conclusion, post-stroke chronic metformin treatment improved functional recovery following MCAO via AMPK-dependent M2 polarization. Modulation of microglia/macrophage polarization represents a novel therapeutic strategy for stroke.     

骨髓基质细胞移植治疗大鼠实验性脑梗死的疗效分析及组织病理学观察

目的 观察大脑中动脉闭塞(MCAO)模型大鼠脑内移植骨髓基质细胞fBMSCs)的治疗作用,分析植入梗死灶不同区域的BMSCs的存活、迁移情况以及植入细胞的行为与脑内微环境中GFAP阳性细胞的形态关系.方法 75只成年SD大鼠采用随机数字表法分为MCAO组(n=50)和BMSCs移植组(n=25),所有动物均采用线栓法制作MCAO 1 h模型,24 h后BMSCs移植组脑内注射BrdU标记的同种异体BMSCs(2x106个),MCAO组注射等量PBS.MCAO前及MCAO后第1(移植前)、3、5、7、10、14天应用加速转轮试验和贴纸去除试验检测神经功能缺损情况;第14天处死动物,取脑组织切片应用HE染色观察两组的缺血病灶范围,行BrdU和GFAP免疫组化染色观察BMSCs在不同区域和不同胶质细胞环境下的存活和迁移情况.结果 BMSCs移植组MCAO后7 d加速转轮试验结果优于MCAO组,差异有统计学意义(P＜0.05);组织学观察发现植入缺血半暗带区的细胞存活数量最多,且向病变方向放射状迁移,植入缺血病灶核心的细胞甚少存活,且无迁移现象.结论 BMSCs脑内移植可改善MCAO后大鼠神经运动功能;活化的星形胶质细胞构成适合植入细胞存活、迁移的环境,而胶质瘢痕阻碍了细胞的迁移.     

慢病毒介导bFGF基因修饰的骨髓基质细胞对脑梗死后血管新生的影响

目的探讨慢病毒介导碱性成纤维细胞生长因子（basic fibrobla stgrowth factor,bFGF）基因修饰的骨髓基质细胞（bone marrow stromal cells,BMSCs）对脑梗死后血管新生的影响。方法利用慢病毒载体介导bFGF基因修饰BMSCs,获得稳定转染bFGF的BMSCs。脑梗死后1d立体定向移植至梗死灶周围。在MCAO术前及术后1、3、7、14d进行神经功能评分。术后14d股静脉注射异硫氰酸荧光素右旋糖酐（FITC-dextran）标记微血管,结合共聚焦显微镜和3DDoctor3．5版软件分析梗死灶周围区微血管的直径、面积及血管分支数目。结果bFGF-BMSCs组术后3d神经功能恢复明显优于对照组与BMSCs组（P〈0．05）,BM—SCs组和bFGF-BMSCs组术后7d及14dmNSS评分显著低于对照组（P〈0．05）,而且bFGF-BMSCs组神经功能恢复好于BMSCs组（P〈O．05）。bFGF-BMSCs组微血管直径、分支数目及面积显著性高于对照组（P〈0．01）和BMSCs组（P〈0．05）。结论bFGF修饰的B^假瞄能更好地促进脑梗死后神经功能恢复及血管新生。     

骨髓基质干细胞移植对缺血性卒中大鼠PSD-95表达的影响

目的 应用骨髓基质干细胞（BMSCs）治疗缺血性卒中大鼠,观察BMSCs的治疗效果,检测突触后密度蛋白-95（PSD-95）的表达水平,进而研究BMSCs治疗缺血性卒中的机制.方法 将40只成年雌性SD大鼠制备成大脑中动脉缺血2h再灌注24h动物模型,随机分为梗死对照组和BMSCs组,每组20只.每组再按梗死后3,7d分为2个亚组,每组10只.梗死对照组于缺血再灌注24 h后经尾静脉注射PBS液1ml,BMSCs组同时经尾静脉注射BMSCs 3×106.所有大鼠于梗死后1,3,7d分别进行神经功能评分,应用免疫组化法测定PSD-95表达水平,用TUNEL测定凋亡细胞水平.结果 （1）神经功能评分：梗死后3,7 d BMSCs组神经功能评分明显低于梗死对照组,差异有统计学意义（t分别为2.138,3.417;P＜0.05）.（2） PSD-95表达：BMSCs组在梗死后3d时PSD-95表达较梗死对照组的表达有增多,但差异无统计学意义;BMSCs组在梗死后7d时PSD-95表达明显多于梗死对照组,且差异有统计学意义（t=6.013,P＜0.05）.（3）TUNEL细胞凋亡染色：梗死后3d时梗死对照组大鼠缺血侧可见许多凋亡细胞,显多于BMSCs组,且差异有统计学意义（t=4.978,P＜ 0.05）.结论 BMSCs移植能促进缺血性卒中大鼠的神经功能的恢复.BMSCs移植后能明显增加缺血性卒中大鼠PSD-95的表达,减少细胞的凋亡,对缺血性卒中有保护作用.     

骨髓基质细胞及血管内皮祖细胞移植对局灶性脑缺血大鼠神经功能恢复的影响

目的 观察经静脉移植骨髓基质细胞(BMSCs)及血管内皮祖细胞(EPCs)后,缺血性脑损伤大鼠神经系统功能恢复情况.方法 40只健康成年Wistar大鼠按随机数字表法分为模型组、移植BMSCs组、移植EPCS组、移植BMSCs/EPCs组,每组10只.线栓法建立大鼠大脑中动脉闭塞(MCAO)模型.造模后24h取1 mLBMSCs、EPCs、BMSCs/EPCs细胞悬液(3×10~6个/mL)分别经尾静脉注射移植入后3组大鼠.模型组大鼠注射等量生理盐水.移植前、移植后1、7、14、28 d,采用旋转试验、躯体感觉试验、神经系统功能评分(NSS)评估各组大鼠神经功能的恢复情况.移植后28d,免疫荧光染色检测各组大鼠缺血脑组织的微血管密度(MVD).结果 移植后第7天,旋转试验显示移植BMSCs/EPCs组大鼠旋转时间长于其他3组,躯体感觉试验和NSS评分分别显示移植BMSCs/EPCs组大鼠移物时间和NSS评分低于其他3组,差异有统计学意义(P<0.05);移植后28 d,免疫荧光染色检测结果显示缺血脑组织MVD明显高于其他3组,差异有统计学意义(P<0.05).结论 静脉BMSCs/EPCS联合移植可增强缺血性脑损伤功能的恢复.     

Endogenous neurogenesis and neovascularization in the neocortex of the rat after focal cerebral ischemia

The present study was designed to examine whether endogenous neurogenesis and neovascularization occur in the neocortex of the ischemic rat brain after unilateral middle cerebral artery occlusion (MCAO). Sprague-Dawley rats were divided into six groups (n = 29): one control group (n = 4) and five groups composed of animals sacrificed at increasing times post-MCAO (2 days and 1, 2, 4, and 8 weeks; n = 5 per group). To determine the presence of neurogenesis and neovascularization in the ischemic brain, nestin, Tuj1, NeuN, GFAP, Tie2, RECA, and 5-bromo-2'-deoxyuridine (BrdU) were analyzed immunohistochemically. In addition, nestin, GFAP, and Tie2 expression was determined by Western blotting. Triple-labeling of nestin, BrdU, and laminin was performed to visualize the interaction between endogenous neurogenesis and neovascularization. The number of BrdU- and nestin-colabeled cells increased markedly in the neocortex and border zone of the ischemic area up to 1 week after MCAO and decreased thereafter. Western blot analysis revealed that the expression of nestin, Tie-2, and GFAP was amplified in the ipsilateral hemisphere 2 days after MCAO and peaked 1 week after MCAO, compared with that in the normal brain. After ischemic injury, nestin- and BrdU-colabeled cells were observed in the vicinity of the endothelial cells lining cerebral vessels in the ipsilateral neocortex of the ischemic brain. Endogenous neurogenesis and neovascularization were substantially activated and occurred in close proximity to one other in the ipsilateral neocortex of the ischemic rat brain.     

变构促红细胞生成素对小鼠脑缺血后神经新生和血管新生的影响

目的 探讨一种氨基酸突变后无促红细胞生成能力的变构促红细胞生成素(mEPO)对大脑中动脉闭塞小鼠神经新生和血管新生的作用.方法 将30只成年雄性C57BL/B6小鼠随机分为Sham组、I/R+ Veh组和I/R+ mEPO组,每组10只.制作小鼠大脑中动脉闭塞缺血(MCAO)模型,I/R+mEPO组小鼠在再灌注即刻腹腔注入mEPO(5 000 IU/kg),I/R+ Veh组小鼠在制模后注入等体积的生理盐水.通过BrdU检测细胞增殖情况,采用转棒试验对小鼠神经功能进行评估.在脑缺血后第14天,检测3组小鼠脑组织丢失比例、神经新生及血管新生情况.结果 用mEPO处理后,I/R+mEPO组小鼠脑组织丢失比例(14.62±5.80)％显著低于I/R+ Veh组小鼠(29.81±7.75)％,差异有统计学意义(P＜0.05);I/R+mEPO组小鼠脑缺血后第3,7天神经功能均有明显改善,第7天即恢复到正常水平,差异有统计学意义(P＜0.05);I/R+mEPO组小鼠脑缺血后第14天BrdU+/NeuN+双阳性细胞数量(36.25±10.53)和BrdU+/Laminin+双阳性细胞数量(25.25±6.34)显著高于Sham组小鼠和I/R+ Veh组小鼠,差异有统计学意义(P＜0.05).结论 mEPO促进了小鼠脑缺血周边区神经新生及血管新生,从而减轻脑组织的损伤程度并提高神经功能.这种无促红细胞生成作用的mEPO可能会成为临床脑血管病的治疗药物.     

Cell proliferation in ependymal/subventricular zone and nNOS expression following focal cerebral ischemia in adult rats

Neuronal nitric oxide synthase (nNOS) regulates neurogenesis in normal developing brain, but the role of nNOS in neurogenesis in the ischemic brain remains unclear. To investigate the temporal and spatial relationship between cell proliferation of the ependymal/subventricular zone (SVZ), a principal neuroproliferative region in the adult brain, and nNOS expression, the male Sprague-Dawley rats weighing 250-350 g were used. The focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). 10 microl of 0.2% fluorescence dye DiI was injected into the right lateral ventricle to prelabel ependymal/subventricular zone cells before ischemia. The rats were killed immediately after ischemia and days 1, 3, 7, 11, 14, 21 and 28 after ischemia. DiI-labeled cell counting was employed to assess cell proliferation. Immunohistochemistry and grayscale analysis were performed to determine nNOS localization and its quantity in the specific regions. Compared with control, the density of DiI-labeled cells in the ipsilateral ependyma/SVZ was significantly higher at days 1, 3, 7 and 11 after ischemia, whereas the quantity of nNOS expression in the ependyma/SVZ adjacent regions was significantly lower at the above time points. Additionally, nNOS positive cells were largely excluded from SVZ, and their long processes did not enter the ependyma/SVZ. Our results indicate that after focal cerebral ischemia, decreased nNOS expression in the ipsilateral ependymal/SVZ adjacent regions might be related to cell proliferation in the ependymal/SVZ.     

Angiogenesis and neuronal remodeling after ischemic stroke

Increased microvessel density in the peri-infarct region has been reported and has been correlated with longer survival times in ischemic stroke patients and has improved outcomes in ischemic animal models.This raises the possibility that enhancement of angiogenesis is one of the strategies to facilitate functional recovery after ischemic stroke.Blood vessels and neuronal cells communicate with each other using various mediators and contribute to the pathophysiology of cerebral ischemia as a unit.In this mini-review,we discuss how angiogenesis might couple with axonal outgrowth/neurogenesis and work for functional recovery after cerebral ischemia.Angiogenesis occurs within 4 to 7 days after cerebral ischemia in the border of the ischemic core and periphery.Post-ischemic angiogenesis may contribute to neuronal remodeling in at least two ways and is thought to contribute to functional recovery.First,new blood vessels that are formed after ischemia are thought to have a role in the guidance of sprouting axons by vascular endothelial growth factor and laminin/β1-integrin signaling.Second,blood vessels are thought to enhance neurogenesis in three stages:1)Blood vessels enhance proliferation of neural stem/progenitor cells by expression of several extracellular signals,2)microvessels support the migration of neural stem/progenitor cells toward the peri-infarct region by supplying oxygen,nutrients,and soluble factors as well as serving as a scaffold for migration,and 3)oxygenation induced by angiogenesis in the ischemic core is thought to facilitate the differentiation of migrated neural stem/progenitor cells into mature neurons.Thus,the regions of angiogenesis and surrounding tissue may be coupled,representing novel treatment targets.     

Angiogenesis after cerebral ischemia

Though the vascular system of the adult brain is extremely stable under normal baseline conditions, endothelial cells start to proliferate in response to brain ischemia. The induction of angiogenesis, primarily in the ischemic boundary zone, enhances oxygen and nutrient supply to the affected tissue. Additionally, the generation of new blood vessels facilitates highly coupled neurorestorative processes including neurogenesis and synaptogenesis which in turn lead to improved functional recovery. To take advantage of angiogenesis as a therapeutic concept for stroke treatment, the knowledge of the precise molecular mechanisms is mandatory. Especially, since a couple of growth factors involved in post-ischemic angiogenesis may have detrimental adverse effects in the brain by increasing vascular permeability. This article summarizes the knowledge of molecular mechanisms of angiogenesis following cerebral ischemia. Finally, experimental pharmacological and cellular approaches to stimulate and enhance post-ischemic angiogenesis are discussed.     

Noggin improves ischemic brain tissue repair and promotes alternative activation of microglia in mice

We previously reported that bone morphogenetic proteins (BMPs) and their endogenous antagonist noggin are expressed in the brain weeks after an ischemic insult. Here, to define their roles in ischemic brain tissue repair and remodeling, we infused recombinant BMP7 or noggin into the ipsilateral ventricle of mice for 2 weeks starting 2 weeks after transient middle cerebral artery occlusion (MCAO). Four weeks after MCAO, we measured ischemic brain volume, functional recovery, and molecules related to neurogenesis and angiogenesis such as synaptophysin, GAP-43, and VEGF. Noggin-treated mice but not BMP7-treated mice showed preserved ipsilateral brain volume and reduced neurological deficits compared with artificial cerebrospinal fluids (aCSF)-treated mice. Noggin treatment also decreased glial scar thickness, increased levels of GAP-43 and VEGF protein, and increased the number of Iba1-positive activated microglia in the ipsilateral brain. Furthermore, noggin treatment decreased M1 markers (IL-1β, TNF-α, IL-12, CCL2 and CD86) and increased M2 markers (IL-1ra, IL-10, arginase 1, CD206 and Ym1) of activated microglia, suggesting a shift from M1 to M2 phenotypes. These results suggest that noggin improves functional recovery from ischemic stroke and enhances alternatively activated microglia, thereby promoting tissue repair and remodeling.     

经鼻给予酸性成纤维细胞生长因子对脑梗死大鼠的血管和神经再生作用

目的研究经鼻给予酸性成纤维细胞生长因子（acidic fibroblast growth factor, aFGF）对脑梗死后神经和血管再生及神经功能恢复的影响。方法健康雄性SD大鼠30只,随机分为aFGF组（n=12）、对照组（n=12）和假手术组（n=6）;aFGF组和对照组大鼠建立大脑中动脉闭塞模型,脑缺血再灌注24h后经鼻分别给予10μg aFGF（200μl）和等容积生理盐水,1次／d,连续7d;同时腹腔注射5-溴脱氧尿核苷（Bromodeoxyuridine,BrdU）50mg／kg,1次/d,连续13d;假手术组操作过程和给药与对照组相同,但不用线栓阻塞大脑中动脉;分别在术前和术后第1、7、14d采用改良神经功能评分评价大鼠神经功能改变情况,并于术后第14d经尾静脉注入异硫氰酸荧光素右旋糖酐（FITC—dextran）,采用免疫组化及激光共聚焦方法分别检测梗死灶周、室管膜下区和纹状体BrdU阳性细胞及微血管的数量。结果术后第7及14d aFGF组神经功能评分显著低于对照组;术后第14d aFGF组缺血侧室管膜下区和纹状体BrdU阳性细胞数与对照组相比均显著增高（P〈0.01）,假手术组仅见少量BrdU阳性细胞;激光共聚焦显示aFGF组梗死灶周微血管数较对照组显著增加（P〈0.05）;同时,与对照组相比经鼻给予aFGF能增加Brdu阳性细胞在血管内皮细胞中的百分比,且有统计学意义（P〈0.05）。结论经鼻给予aFGF能有效促进神经和血管再生,改善脑缺血后神经功能评分,对于治疗脑梗死具有潜在的应用前景。     

骨髓间充质干细胞立体定向移植治疗大鼠脑缺血损伤的实验研究

目的观察立体定向移植骨髓间充质干细胞(BMSC)治疗MCAO大鼠的效果并探讨其可能机制。方法用改良线拴法制作大脑中动脉闭塞(MCAO)模型。60只模型大鼠随机分为移植组(A组)、磷酸盐缓冲液溶液组(B组)与假手术组(C组)。在模型建立后7 d,通过立体定向方式将1×106个BMSCs移植入A组大鼠损伤侧纹状体,B组大鼠以同样方式在同样部位移植等体积的磷酸盐缓冲液,C组完成立体定向过程,但无液体注入。应用改良大鼠神经功能缺损评分(m NSS评分)、水迷宫测试观察大鼠神经功能恢复状况,并取大鼠脑组织行免疫组织化学染色。结果 A组m NSS评分优于B组、C组(P0.05);A组逃避潜伏期明显缩短(P0.05);跨越平台次数明显增多(P0.05)。A组大鼠在脑损伤中心及周围区,可见Brdu单染阳性细胞及Brdu+BDNF、Brdu+GFAP、Brdu+v WF、Brdu+VEGF双染阳性细胞。结论立体定向移植BMSCs可以显著改善MCAO大鼠神经功能恢复。