骨髓间质干细胞移植减轻犬急性脑梗死模型的缺血性脑损伤研究

目的观察骨髓间质干细胞(BMSCs)对犬急性缺血脑组织的保护作用,并探讨其可能的机制。方法将24只成年杂交犬随机分为治疗组及对照组,DSA引导下行自体血栓栓塞大脑中动脉闭塞缺血模型制作,并抽取骨髓提取BMSCs,传代并给予4’,6-二脒基-2-苯基吲哚(DAPI)标记;1周后开颅行多点脑内注射BMSCs移植;移植后1周行脑DWI序列扫描,计算梗死灶体积;4周后将犬处死,每组随机选择6只动物取脑标本行TTC染色测定梗死灶体积;另外6只动物进行HE染色、VG染色、TUNEL染色评价脑损伤情况;免疫荧光染色了解脑源性神经营养因子(BDNF)、碱性成纤维生长因子(b FGF)、胰岛素样生长因子1(IGF-1)和血管内皮生长因子(VEGF)的表达情况。结果治疗组梗死灶内广泛存在DAPI阳性细胞。治疗组的梗死灶体积明显小于对照组,P0.01。治疗组梗死灶范围、梗死灶内细胞坏死、胶质增生和胶质瘢痕均较对照组减轻。治疗组凋亡细胞明显少于对照组,P0.05。治疗组细胞因子BDNF、BFGF、IGF-1和VEGF表达阳性的细胞均显著多于对照组。结论脑梗死后给予BMSCs移植,BMSCs能存活并自行向梗死灶迁移,并发挥脑保护作用,其机制可能和分泌多种神经营养因子有关。

Bone marrow mesenchymal stem cell transplantation reduces ischemic brain injury in a dog model of acute cerebral infarction

Objective To investigate the protective effect of bone marrow mesenchymal stem cells (BMSCs) on acute ischemic brain tissue and possible mechanisms.Methods A total of 24 hybridized adult dogs were randomized into treatment group and control group.A model of ischemia was established by digital subtraction angiography-guided middle cerebral artery occlusion using autologous blood clots.Bone marrow aspiration was performed to collect BMSCs,and then BMSCs were subcultured and labeled by 4',6-diamidino-2-phenylindole (DAPI).Craniotomy was performed at 1 week after modeling and BMSCs were transplanted via intracerebral injection at multiple sites.At 1 week after transplantation,brain diffusion-weighted imaging was performed to calculate infarct volume.The dogs were sacririced at 4 weeks after transplantation,6 dogs were randomly selected from each group to collect brain tissue,and TTC staining was performed to measure infarct volume;HE staining,Van Gieson staining,and TUNEL staining were performed for the other 6 dogs in each group to evaluate brain injury.Immunofluorescent staining was performed to measure the expression of brain-derived neurotrophic factor (BDNF),basic fibroblast growth factor (bFGF),insulin-like growth factor-1 (IGF-1),and vascular endothelial growth factor (VEGF).Results The treatment group had many DAPI-positive cells widely dispersed in infarct.The treatment group had a significantly smaller infarct volume than the control group (P ＜ 0.01).Compared with the control group,the treatment group had significant alleviation in infarct extent,cell necrosis in infarct,gliosis,and glial scar.The treatment group had a significantly lower number of apoptotic cells than the control group (P ＜0.05).Compared with the control group,the treatment group had significantly higher numbers of cells with positive expression of BDNF,bFGF,IGF-1,and VEGF.Conclusions When transplantation of BMSCs is performed after cerebral infarction,BMSCs can survive,migrate to infarct,and then protect the brain,possibly by secreting various neurotrophic factors.