Bone marrow mesenchymal stem cells repair spinal cord ischemia/reperfusion injury by promoting axonal growth and anti-autophagy

Bone marrow mesenchymal stem cells can differentiate into neurons and astrocytes after trans- plantation in the spinal cord of rats with ischemia/reperfusion injury. Although bone marrow mesenchymal stem cells are known to protect against spinal cord ischemia/reperfusion injury through anti-apoptotic effects, the precise mechanisms remain unclear. In the present study, bone marrow mesenchymal stem cells were cultured and proliferated, then transplanted into rats with ischemia/reperfusion injury via retro-orbital injection. Immunohistochemistry and immunofluorescence with subsequent quantification revealed that the expression of the axonal regeneration marker, growth associated protein-43, and the neuronal marker, microtubule-as- sociated protein 2, significantly increased in rats with bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Fur- thermore, the expression of the autophagy marker, microtubule-associated protein light chain 3B, and Beclin 1, was significantly reduced in rats with the bone marrow mesenchymal stem cell transplantation compared with those in rats with spinal cord ischemia/reperfusion injury. Western blot analysis showed that the expression of growth associated protein-43 and neuro- filament-H increased but light chain 3B and Beclin 1 decreased in rats with the bone marrow mesenchymal stem cell transplantation. Our results therefore suggest that bone marrow mes- enchymal stem cell transplantation promotes neurite growth and regeneration and prevents autophagy. These responses may likely be mechanisms underlying the protective effect of bone marrow mesenchymal stem cells against spinal cord ischemia/reperfusion injury.     

Human bone marrow mesenchymal stem cell transplantation attenuates axonal injury in stroke rats

Previous studies have shown that transplantation of human bone marrow mesenchymal stem cells promotes neural functional recovery after stroke, but the neurorestorative mechanisms remain largely unknown. We hypothesized that functional recovery of myelinated axons may be one of underlying mechanisms. In this study, an ischemia/reperfusion rat model was established using the middle cerebral artery occlusion method. Rats were used to test the hypothesis that intravenous transplantation of human bone marrow mesenchyrnal stem cells through the femoral vein could exert neuroprotective effects against cerebral ischemia via a mechanism associated with the ability to attenuate axonal injury. The results of behavioral tests, infarction volume analysis and immunohistochemistry showed that cerebral ischemia caused severe damage to the myelin sheath and axons. After rats were intravenously transplanted with human bone marrow mesenchymal stem cells, the levels of axon and myelin sheath-related proteins, including microtubule-associated protein 2, myelin basic protein, and growth-associated protein 43, were elevated, infarct volume was decreased and neural function was improved in cerebral ischemic rats. These findings suggest that intravenously transplanted human bone marrow mesenchymal stem cells promote neural function. Possible mechanisms underlying these beneficial effects include resistance to demyelination after cerebral ischemia, prevention of axonal degeneration, and promotion of axonal regeneration.     

丁基苯酞加强造血干细胞移植及内源性干细胞动员治疗脑梗死的效应

Exogenous stem cell transplantation and endogenous stem cell mobilization are both effective for the treatment of acute cerebral infarction. The compound dl-3-butylphthalide is known to improve microcirculation and help brain cells at the infarct loci. This experiment aimed to investigate the effects of dl-3-butylphthalide intervention based on the transplantation of hematopoietic stem cells and mobilization of endogenous stem cells in a rat model of cerebral infarction, following middle cerebral artery occlusion. Results showed that neurological function was greatly improved and infarct volume was reduced in rats with cerebral infarction. Data also showed that dl-3-butylphthalide can promote hematopoietic stem cells to transform into vascular endothelial cells and neuronal-like cells, and also enhance the therapeutic effect on cerebral infarction by hematopoietic stem cell transplantation and endogenous stem cell mobilization.     

Bone marrow mesenchymal stem cell therapy in ischemic stroke：mechanisms of action and treatment optimization strategies

Animal and clinical studies have conifrmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction, angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action, and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke. We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.     

Is longer sevoflurane preconditioning neuroprotective in permanent focal cerebral ischemia?

Sevoflurane preconditioning has neuroprotective effects in the cerebral ischemia/reperfusion model. However, its influence on permanent cerebral ischemia remains unclear. In the present study, the rats were exposed to sevoflurane for 15, 30, 60, and 120 minutes, followed by induction of perma-nent cerebral ischemia. Results demonstrated that 30-and 60-minute sevoflurane preconditioning significantly reduced the infarct volume at 24 hours after cerebral ischemia, and 60-minute se-voflurane preconditioning additionally reduced the number of TUNEL-and caspase-3-positive cells in the ischemic penumbra. However, 120-minute sevoflurane preconditioning did not show evident neuroprotective effects. Moreover, 60-minute sevoflurane preconditioning significantly attenuated neurological deficits and infarct volume in rats at 4 days after cerebral ischemia. These findings in-dicated that 60-minute sevoflurane preconditioning can induce the best neuroprotective effects in rats with permanent cerebral ischemia through the inhibition of apoptosis.     

660 nm red light-enhanced bone marrow mesenchymal stem cell transplantation for hypoxic-ischemic brain damage treatment

Bone marrow mesenchymal stem cell transplantation is an effective treatment for neonatal hypoxic-ischemic brain damage. However, the in vivo transplantation effects are poor and their survival, colonization and differentiation efficiencies are relatively low. Red or near-infrared light from 600–1,000 nm promotes cellular migration and prevents apoptosis. Thus, we hypothesized that the combination of red light with bone marrow mesenchymal stem cell transplantation would be effective for the treatment of hypoxic-ischemic brain damage. In this study, the migration and colonization of cultured bone marrow mesenchymal stem cells on primary neurons after oxygen-glucose deprivation were detected using Transwell assay. The results showed that, after a 40-hour irradiation under red light-emitting diodes at 660 nm and 60 mW/cm2, an increasing number of green fluorescence-labeled bone marrow mesenchymal stem cells migrated towards hypoxic-ischemic damaged primary neurons. Meanwhile, neonatal rats with hypoxic-ischemic brain damage were given an intraperitoneal injection of 1 × 106 bone marrow mesenchymal stem cells, followed by irradiation under red light-emitting diodes at 660 nm and 60 mW/cm2 for 7 successive days. Shuttle box test results showed that, after phototherapy and bone marrow mesenchymal stem cell transplantation, the active avoidance response rate of hypoxic-ischemic brain damage rats was significantly increased, which was higher than that after bone marrow mesenchymal stem cell transplantation alone. Experimental findings indicate that 660 nm red light emitting diode irradiation promotes the migration of bone marrow mesenchymal stem cells, thereby enhancing the contribution of cell transplantation in the treatment of hypoxic-ischemic brain damage.     

Intravenous transplantation of bone marrow mesenchymal stem cells promotes neural regeneration after traumatic brain injury

To investigate the supplement of lost nerve cells in rats with traumatic brain injury by intravenous administration of allogenic bone marrow mesenchymal stem cells, this study established a Wistar rat model of traumatic brain injury by weight drop impact acceleration method and administered 3 × 106 rat bone marrow mesenchymal stem cells via the lateral tail vein. At 14 days after cell transplantation, bone marrow mesenchymal stem cells differentiated into neurons and astrocytes in injured rat cerebral cortex and rat neurological function was improved significantly. These findings suggest that intravenously administered bone marrow mesenchymal stem cells can promote nerve cell regeneration in injured cerebral cortex, which supplement the lost nerve cells.     

Neuroprotective effects of total saponins from Rubus parvifolius L. on cerebral ischemia/ reperfusion injury in rats

This study examines the neuroprotective effects and mechanisms of action of total saponins from Rubus parvifolius L. (TSRP) on focal cerebral ischemia and reperfusion injury in rats. Focal cerebral ischemia and reperfusion injury was performed in rats using the suture method. The results indicate that intragastric injection of TSRP, at 5, 10 and 20 mg/kg, could decrease neurological impairment, reduce cerebral infarct volume, diminish pathological changes, and significantly inhibit the apoptosis of neurons surrounding the ischemic area. In addition, TSRP upregulated the expression of the anti-apoptotic factor Bcl-2, at the protein and mRNA levels, and it downregulated the expression of the pro-apoptotic factor Bax, at the protein and mRNA levels. These findings indicate that TSRP protects against cerebral ischemia/reperfusion injury, and that it may do so by regulating the expression of Bcl-2 and Bax.     

Total flavonoid of Litsea coreana leve exerts anti-oxidative effects and alleviates focal cerebral ischemia/reperfusion injury

In this study, we hypothesized that total flavonoid of Litsea coreana leve （TFLC） protects against focal cerebral ischemia/reperfusion injury. TFLC （25, 50, 100 mg/kg） was administered orally to a rat model of focal ischemia/reperfusion injury, while the free radical scavenging agent, edaravone, was used as a positive control drug. Results of neurological deficit scoring, 2,3,5-triphenyl tetrazolium chloride staining, hematoxylin-eosin staining and biochemical tests showed that TFLC at different doses significantly alleviated cerebral ischemia-induced neurological deficits and histopathological changes, and reduced infarct volume. Moreover, it suppressed the increase in the levels of nitrates plus nitrites, malondialdehyde and lactate dehydrogenase, and it diminished the reduction in glu- tathione, superoxide dismutase and catalase activities induced by cerebral ischemia/reperfusion injury. Compared with edaravone, the protective effects of TFLC at low and medium doses （25, 50 mg/kg） against cerebral ischemia/reperfusion injury were weaker, while the protective effects at high dose （100 mg/kg） were similar. Our experimental findings suggest that TFLC exerts neuroprotective effects against focal cerebral ischemia/reperfusion injury in rats, and that the effects may be asso- ciated with its antioxidant activities.     

重组人粒细胞集落刺激因子对局灶性脑缺血大鼠的抗凋亡作用

The neuroprotective effects of granulocyte colony-stimulating factor in cerebral ischemia/reperfusion injury are currently contentious. The present study examined the effects of subcutaneous injection of recombinant human granulocyte colony-stimulating factor (50 μg/kg) over 5 days in a model of cerebral ischemia/reperfusion with intraluminal filament occlusion in rats. The results indicated that recombinant human granulocyte colony-stimulating factor reduced brain infarct volume following cerebral ischemia/reperfusion injury in rats, down-regulated the expression of caspase-3 mRNA (a key protease for apoptosis in the cerebral ischemia zone), lowered the rate of neuronal apoptosis in the cerebral ischemia zone, and notably ameliorated neurological function. These results indicate that recombinant human granulocyte colony-stimulating factor has anti-apoptotic effects on neurons following focal cerebral ischemia/reperfusion injury, and exerts neuroprotective effects.     

12 hours after cerebral ischemia is the optimal time for bone marrow mesenchymal stem cell transplantation

Cell therapy using stem cell transplantation against cerebral ischemia has been reported. However, it remains controversial regarding the optimal time for cell transplantation and the transplantation route. Rat models of cerebral ischemia were established by occlusion of the middle cerebral artery. At 1, 12 hours, 1, 3, 5 and 7 days after cerebral ischemia, bone marrow mesenchymal stem cells were injected via the tail vein. At 28 days after cerebral ischemia, rat neurological function was evaluated using a 6-point grading scale and the pathological change of ischemic cerebral tissue was observed by hematoxylin-eosin staining. Under the fluorescence microscope, the migration of bone marrow mesenchymal stem cells was examined by PKH labeling. Caspase-3 activity was measured using spectrophotometry. The optimal neurological function recovery, lowest degree of ischemic cerebral damage, greatest number of bone marrow mesenchymal stem cells migrating to peri-ischemic area, and lowest caspase-3 activity in the ischemic cerebral tissue were observed in rats that underwent bone marrow mesenchymal stem cell transplantation at 12 hours after cerebral ischemia. These findings suggest that 12 hours after cerebral ischemia is the optimal time for tail vein injection of bone marrow mesenchymal stem cell transplantation against cerebral ischemia, and the strongest neuroprotective effect of this cell therapy appears at this time.     

脂肪来源神经干细胞移植局灶性脑缺血模型大鼠的血管新生

背景：脂肪组织来源的神经干细胞移植可改善脑缺血大鼠神经功能,但其机制尚不明确。 目的：观察人脂肪组织来源神经干细胞移植对大鼠局灶性脑缺血后血管新生的影响。 方法：体外培养脂肪基质细胞,诱导分化为神经干细胞。60只健康雄性SD大鼠分为4组：正常组6只,假手术组6只,缺血对照组24只,移植治疗组24只。后两组线栓法制作大鼠大脑中动脉缺血2 h再灌注模型,又分为缺血2 h再灌注7,14,21,28 d组,每个时点各6只。假手术组不闭塞大脑中动脉。造模成功后24 h,移植治疗组经尾静脉移植人脂肪组织来源神经干细胞悬液,细胞浓度为2×109 L-1;缺血对照组经尾静脉注射生理盐水。免疫组织化学法进行微血管密度计数,观察脑缺血区血管增生情况。 结果与结论：免疫组织化学结果显示,与缺血对照组比较,移植治疗组缺血2 h再灌注7,14,21,28 d的微血管密度值均显著高于缺血对照组,差异有显著性意义(P < 0.05~0.01)。提示脂肪组织来源的神经干细胞移植可促进脑缺血区新生血管的形成。     

骨髓间充质干细胞对局灶脑缺血再灌注损伤的超早期干预

摘要：目的　探讨骨髓间充质干细胞(BMSCs) 对大鼠脑缺血再灌注损伤保护作用及机制。方法　雄性SD大鼠72只,以线栓法制成缺血再灌注模型,随机分为2组：溶剂对照组;BMSCs移植组。在缺血再灌注后1天、3天、6天分别行神经功能检测、TTC染色、免疫组化法检测Survivin、caspase-3表达,TUNEL法检测凋亡细胞表达。结果　与溶剂对照组比较,在梗死脑组织中移植骨髓间充质干细胞BMSCs后,可使大鼠神经功能有所恢复,在大鼠大脑中动脉局灶脑缺血90分钟再灌注3天及6天神经功能评分比较高,有统计学意义;TTC染色脑梗死体积百分比在缺血再灌注第3天、第6天较溶剂对照组分别减少2.13%和2.10%,有统计学意义。单纯BMSCs移植组比较对照组在缺血再灌注后1天、3天、6天缺血侧皮层Survivin表达增高、caspase-3表达降低,凋亡细胞减少,均有统计学意义。结论　脑缺血部位脑实质单纯 BMSCs 移植能够改善缺血后神经功能,减少脑缺血后梗死体积,可能通过增加脑缺血再灌注损伤部位Survivin蛋白的表达,降低凋亡相关蛋白Caspase-3表达,减少凋亡细胞数量发挥作用     

Transplantation of Flk-1+ human bone marrow-derived mesenchymal stem cells promotes angiogenesis and neurogenesis after cerebral ischemia in rats

Transplantation of bone marrow‐derived mesenchymal stem cells (BMSCs) is a potential therapy for cerebral ischemia. Although BMSCs‐induced angiogenesis is considered important for neurological functional recovery, the neurorestorative mechanisms are not fully understood. We examined whether BMSCs‐induced angiogenesis enhances cerebral tissue perfusion and creates a suitable microenvironment within the ischemic brain, which in turn accelerates endogenous neurogenesis and leads to improved functional recovery. Adult female rats subjected to 2 h middle cerebral artery occlusion (MCAO) were transplanted with a subpopulation of human BMSCs from male donors (Flk‐1+ hBMSCs) or saline into the ipsilateral brain parenchymal at 3 days after MCAO. Flk‐1+ hBMSCs‐treated rats exhibited significant behavioral recovery, beginning at 2 weeks after cerebral ischemia compared with controls. Moreover, rats treated with Flk‐1+ hBMSCs showed increased glucose metabolic activity and reduced infarct volume. Flk‐1+ hBMSCs treatment significantly increased the expression of vascular endothelial growth factor and brain‐derived neurotrophic factor, promoted angiogenesis, and facilitated cerebral blood flow in the ischemic boundary zone. Further, Flk‐1+ hBMSCs treatment enhanced proliferation of neural stem/progenitor cells (NSPCs) in the subventricular zone and subgranular zone of the hippocampus. Finally, more NSPCs migrated toward the ischemic lesion and differentiated to mature neurons or glial cells with less apoptosis in Flk‐1+ hBMSCs‐treated rats. These data indicate that angiogenesis induced by Flk‐1+ hBMSCs promotes endogenous neurogenesis, which may cause functional recovery after cerebral ischemia.     

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.     

厄贝沙坦对大鼠局灶性脑缺血再灌注后炎症反应的影响

目的观察厄贝沙坦对大鼠局灶性脑缺血再灌注后脑内及外周炎症反应的影响。方法采用改良Longa方法制备大鼠大脑中动脉阻塞(middle cerebralartery occlusion,MCAO)模型,于缺血90min再灌注后24h和72h进行梗死体积的测量,采用免疫组化和ELISA方法测量脑内和外周血的粘附分子。结果厄贝沙坦可以显著减少局灶性脑缺血再灌注后24h和72h的梗死体积(均P<0.01),改善神经功能(均P<0.01);降低脑内ICAM-1、VCAM-1的表达及其外周血浆中可溶性的形式sICAM-1、sVCAM-1蛋白的水平(均P<0.05)。结论厄贝沙坦可以降低粘附分子的表达,减少梗死体积,改善神经功能,对脑缺血再灌注起保护作用。     

同种异体大鼠骨髓间充质干细胞移植在肠缺血-再灌注损伤肠道中的定植及其分化效应

背景：小肠对缺血缺氧极为敏感,其发生缺血-再灌注时可出现严重的组织损伤,骨髓间充质干细胞具有多向分化潜能,可通过多种途径参与受损组织的修复。 目的：观察同种异体大鼠骨髓间充质干细胞移植后在肠缺血-再灌注损伤中肠道的定植情况和治疗效果。 方法：Wistar雌性大鼠分为3组,假手术组剖开腹腔后即予以缝合;其余大鼠建立肠缺血-再灌注模型,对照组肠道缺血-再灌注后仅输入生理盐水;治疗组鼠尾静脉注射Wistar雄性大鼠骨髓间充质干细胞。治疗后分别于12,24 h,3,7,14,28 d分批取空肠组织,制作冰冻切片在荧光显微镜观察供体细胞在受体肠道的分布,空肠组织匀浆后行RT-PCR检测雄性大鼠的性别决定基因,并检测肠组中丙二醛和超氧化物歧化酶含量。 结果与结论：冰冻切片在荧光显微镜下观察,未见供体细胞在受体肠绒毛表面定植。雌性大鼠肠组织中性别决定基因的RT-PCR检测结果为：3 d阳性率为50%,7 d阳性率66.6%,14 d阳性率33.3%,28 d阳性率为16.6%。骨髓间充质干细胞治疗组第12,24小时,3,7天的空肠组织中的丙二醛水平低于对照组、超氧化物歧化酶含量高于对照组。结果提示,同种异体大鼠骨髓间充质干细胞可在受体肠缺血-再灌注损伤的肠道内定植,并可加速肠道损伤的恢复,其发挥疗效并非直接分化,而是主要是通旁分泌的形式促进机体内源性修复。