Neuregulin-1β Plays a Neuroprotective Role by Inhibiting the Cdk5 Signaling Pathway after Cerebral Ischemia-Reperfusion Injury in Rats

This study investigated the effects of neuregulin-1β (NRG1β) after middle cerebral artery occlusion/reperfusion (MCAO/R) in rats to evaluate whether they occur via the cyclin-dependent kinase (Cdk)5 signaling pathway. One hundred adult male Wistar rats were randomly divided into sham, MCAO/R, treatment (NRG1β), inhibitor (roscovitine; Ros), and inhibitor + treatment (Ros?+?NRG1β) groups. The MCAO/R model was established using the intraluminal thread method. The neurobehavioral function was evaluated by the modified neurological severity score (mNSS). The cerebral infarction volume (CIV) was measured by triphenyl tetrazolium chloride (TTC) staining. Morphological changes were observed by hematoxylin-eosin (HE) staining. The apoptotic cell index (ACI) was detected by the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Immunohistochemistry and Western blotting were performed to detect the expression of calpain 1, p35/p25 (regulatory binding partners of Cdk5), Cdk5, and p-Tau in neurons. The neuronal morphology in the MCAO/R, NRG1β, Ros?+?NRG1β, and Ros groups differed compared to the sham group; the mNSS, CIV, ACI, and the expression of calpain 1, p35/p25, Cdk5, and p-Tau were significantly increased in all four groups (P?<?0.05). In the NRG1β, Ros and Ros?+?NRG1β groups, the neuronal morphology was significantly improved compared to the MCAO/R group, as were the mNSS, CIV, and ACI. The levels of calpain 1, p35/p25, and p-Tau were decreased compared with the MCAO/R group (P?<?0.05), while the Cdk5 expression was not significantly different (P?>?0.05). NRG1β may exert neuroprotective effects by inhibiting the expression of calpain 1, p35/p25, and p-Tau after cerebral ischemia-reperfusion injury.     

神经调节素1β通过激活Sirt1信号通路抑制自噬改善大鼠脑缺血再灌注损伤研究

目的 探讨神经调节素1β(neuregulin1β,NRG1β)是否通过抑制自噬减轻大鼠大脑中动脉缺血再灌注（middle cerebral artery occlusion reperfusion,MCAO/R）损伤,以及对沉默信息调节因子1(silent information regulator protein 1,Sirt1)信号通路的影响。方法 将210只健康雄性SD大鼠随机分为假手术组（Sham组）、模型组（MCAO/R组）、治疗组（NRG1β组）、激动剂组（SRT501组）、激动剂+治疗组（SRT501+NRG1β组）、抑制剂组（EX527组）和抑制剂+治疗组（EX527+NRG1β组）,每组30只。采用改良线栓法建立MCAO/R模型,线栓由颈外动脉插入颈内动脉18～22 mm,堵塞左侧大脑中动脉起始部。缺血2 h后,缓慢拔出线栓,恢复脑血流22 h。EX527(5 mg/kg)、SRT501(100 mg/kg)于术前30 min腹腔注射,NRG1β(2μg/kg)于拔出线栓后由微量注射器注入颈内动脉。脑缺血2 h、再灌注22 h后采用改良神经损伤严重程度评分（modi...     

High-potassium preconditioning enhances tolerance to focal cerebral ischemia-reperfusion injury through anti-apoptotic effects in male rats

Imbalances between cellular K⁺ efflux and influx are considered to be involved in cerebral ischemia-reperfusion (I/R) injury. High-potassium pretreatment alleviates this injury, but the underlying molecular mechanism is unclear. In this study, we sought to investigate whether high-potassium preconditioning enhances cerebral tolerance to I/R injury through an anti-apoptotic mechanism. Adult male Sprague-Dawley rats were randomly divided into four groups (n = 40/group): a sham-operated group, normal saline group (3.2 ml/kg saline, intravenous (IV)), and low-dose and high-dose potassium chloride (KCl) groups (40 and 80 mg/kg KCl solution, IV, respectively). Subsequently, the rats underwent 90 min of middle cerebral artery occlusion (MCAO) followed by 24 hr of reperfusion (MCAO/R). Neurological deficit scores, 2,3,5-triphenyltetrazolium chloride (TTC) staining, hematoxylin and eosin staining, and TUNEL assay were used to assess neural injury. The expression of apoptotic proteins, brain potassium levels, mitochondrial function and oxidative stress were detected to explore the potential mechanism. After 24 hr of reperfusion, in both KCl treatment groups, neurological deficits and the cerebral infarct volume were reduced, and the apoptosis index of neurons was decreased. Furthermore, high-potassium preconditioning increased brain K⁺, adenosine triphosphate (ATP), cytochrome c oxidase (COX) levels, reduced malondialdehyde level, improved Na⁺/K⁺-ATPase, succinic dehydrogenase and superoxide dismutase activities, upregulated anti-apoptotic protein expression, and downregulated pro-apoptotic protein expression. This study suggests that high-potassium preconditioning enhanced cerebral tolerance to I/R injury in a rat MCAO/R model. The protective mechanism may involve apoptosis inhibition via preservation of intracellular K⁺ and improvement of mitochondrial function.     

人脐带血间充质干细胞移植对脑梗死大鼠外周血Foxp3表达的影响

目的探讨人脐带血间充质干细胞(mesenchymal stem cells,MSC)移植对脑梗死大鼠外周血Foxp3调节性T细胞改善缺血性脑损害的可能机制。方法选择SD大鼠40只,随机分为假手术组、对照组、生理盐水组、MSC组,每组10只。各组大鼠分别测定1 d、7 d、14 d、28 d外周血单个核细胞中Foxp3 mRNA表达和神经功能缺损评分;TUNEL法检测神经细胞凋亡数。结果 MSC组14 d、28 d神经功能缺损评分明显低于对照组及生理盐水组[(6.1±1.4)分vs(7.3±1.1)分,(7.3±0.9)分;(5.2±1.0)分vs(6.2±1.0)分,(6.3±0.5)分;P0.05];28 d凋亡细胞数明显少于对照组及生理盐水组(P0.05)。对照组、生理盐水组及MSC组1 d、7 d、14 d、28 d外周血Foxp3 mRNA表达明显高于假手术组,差异有统计学意义(P0.01)。MSC组1 d、7 d外周血Foxp3 mRNA表达明显高于对照组和生理盐水组,差异有统计学意义(P0.05)。结论 MSC移植改善大鼠急性脑缺血神经功能恢复的机制之一,可能与上调免疫炎性反应初期Foxp3 mRNA表达有关。     

C1q肿瘤坏死因子相关蛋白6破坏大鼠脑缺血再灌注损伤后血脑屏障的机制研究

目的 探讨C1q肿瘤坏死因子相关蛋白6（C1q and tumor necrosis factor related protein 6，C1QTNF6） 对大鼠大脑中动脉缺血再灌注（middle cerebral artery occlusion reperfusion，MCAO/R）后血脑屏障及内皮细胞闭合蛋白（occludin）和闭锁小带蛋白-1（zonula occludens 1，ZO-1）表达的影响。      

Schisandrin B improves cerebral ischemia and reduces reperfusion injury in rats through TLR4/NF-κB signaling pathway inhibition

ABSTRACT

It has been established that poor outcomes in ischemic stroke patients are associated with the post-reperfusion inflammatory response and up-regulation of TLR4. Therefore, suppression of the TLR4 signaling pathway constitutes a potential neuroprotective therapeutic strategy. Schisandrin B, a compound extracted from Schisandra chinensis, has been shown to possess anti-inflammatory and neuroprotective properties. However, the mechanism remains unclear. In the present study, the therapeutic effect of schisandrin B was assessed following cerebral ischemia and reperfusion (I/R) injury in a model of middle cerebral artery occlusion and reperfusion (MCAO/R) in rats. The effects of schisandrin B were investigated with particular emphasis on TLR4 signal transduction and on the inflammatory response. Schisandrin B treatment conferred significant protection against MCAO/R injury, as evidenced by decreases in infarct volume, neurological score, and the number of apoptotic neurons and inflammatory signaling molecules.     

Accumulation of a repulsive axonal guidance molecule RGMa in amyloid plaques: a possible hallmark of regenerative failure in Alzheimer's disease brains

J. Satoh, H. Tabunoki, T. Ishida, Y. Saito and K. Arima (2013) Neuropathology and Applied Neurobiology 39, 109–120 Accumulation of a repulsive axonal guidance molecule RGMa in amyloid plaques: a possible hallmark of regenerative failure in Alzheimer's disease brains Aims: RGMa is a repulsive guidance molecule that induces the collapse of axonal growth cones by interacting with the receptor neogenin in the central nervous system during development. It remains unknown whether RGMa plays a role in the neurodegenerative process of Alzheimer's disease (AD). We hypothesize that RGMa, if it is concentrated on amyloid plaques, might contribute to a regenerative failure of degenerating axons in AD brains. Methods: By immunohistochemistry, we studied RGMa and neogenin (NEO1) expression in the frontal cortex and the hippocampus of 6 AD and 12 control cases. The levels of RGMa expression were determined by qRT‐PCR and Western blot in cultured human astrocytes following exposure to cytokines and amyloid beta (Aβ) peptides. Results: In AD brains, an intense RGMa immunoreactivity was identified on amyloid plaques and in the glial scar. In the control brains, the glial scar and vascular foot processes of astrocytes expressed RGMa immunoreactivity, while oligodendrocytes and microglia were negative for RGMa. In AD brains, a small subset of amyloid plaques expressed a weak NEO1 immunoreactivity, while some reactive astrocytes in both AD and control brains showed an intense NEO1 immunoreactivity. In human astrocytes, transforming growth factor beta‐1 (TGFβ₁), Aβ_1–40 or Aβ_1–42 markedly elevated the levels of RGMa, and TGFβ₁ also increased its own levels. Coimmunoprecipitation analysis validated the molecular interaction between RGMa and the C‐terminal fragment β of amyloid beta precursor protein (APP). Furthermore, recombinant RGMa protein interacted with amyloid plaques in situ. Conclusions: RGMa, produced by TGFβ‐activated astrocytes and accumulated in amyloid plaques and the glial scar, could contribute to the regenerative failure of degenerating axons in AD brains.     

Do different reperfusion methods affect the outcomes of stroke induced by MCAO in adult rats?

There are two patterns of ischemia/reperfusion (I/R) models used in rat middle cerebral artery occlusion (MCAO) I/R models, which differ in the use of unilateral or bilateral carotid artery reperfusion. The primary difference between the two patterns of I/R models is the complexity of the surgery procedure. However, researchers in this field have no idea whether there are any differences in outcomes of these two methods. In this study, we investigated the effects of the two methods on neurological deficits, infarct volume, blood–brain barrier (BBB) integrity and brain derived neurotrophic factor (BDNF) expression. Through evaluating the current way of bilateral common carotid artery reperfusion, we tried to find whether it could be replaced by an easier way. We found that there were no statistical significant differences between the different methods in infarct volume, neurological deficits, BBB integrity, and the level of BDNF (P > 0.05). These data demonstrated that different methods did not affect the neurological deficits, infarct volume, BBB integrity, and the BDNF protein level, which provides reference when we use an experimental stroke. These results suggest that the two methods have similar capability for inducing cerebral I/R injury and can be interchanged.     

全反式维甲酸对缺血再灌注大鼠血脑屏障通透性的影响

目的探究全反式维甲酸对缺血再灌注大鼠血脑屏障通透性的影响。方法将180只健康雄性大鼠完全随机分为假手术组(Sham),缺血再灌注组(I/R)和全反式维甲酸干预组(ATRA),每组60只,使用Zea Longa法制作局灶性脑缺血再灌注模型。在维甲酸干预(30 mg/kg)后不同时间点(1 d、3 d、7 d)分别通过测定大鼠脑梗死体积、伊文思蓝(EB)含量、基质金属蛋白酶-9(MMP-9)的表达来观察大鼠血脑屏障通透性的变化。结果缺血再灌注后脑梗死体积及EB含量均在1 d达高峰,之后逐渐下降,1 d及7 d时ATRA组脑梗死体积及EB含量均明显低于I/R组(P0.05)。MMP-9的表达3 d达高峰,免疫组化法显示3 d和7 d时ATRA组低于I/R组(P0.05),免疫印迹法显示1 d、3 d、7 d时ATRA组低于I/R组(P0.05)。结论全反式维甲酸可以减轻再灌注后血脑屏障的破坏。     

动员自体骨髓干细胞对大鼠脑缺血／再灌注损伤及细胞凋亡的影响

目的 探讨应用G-CSF动员自体骨髓干细胞对大鼠脑缺血／再灌注损伤及细胞凋亡的影响。方法 应用线栓法制备大鼠局灶性大脑中动脉栓塞／再灌注(MCAO／R)模型，应用粒细胞集落刺激因子(G-GSF)刺激自体骨髓干细胞分裂增殖，并用5-溴脱氧尿核苷(Brdu)标记。观察大鼠神经病学评分，HE染色和免疫组化检测脑缺血区病理改变及CD34和Brdu阳性细胞，原位末端标记法(TUNEL法)观察细胞凋亡。结果 模型动员组大鼠脑缺血／再灌注后24h，大量炎症细胞浸润。再灌注后48h，缺血区可见CD34和Brdu阳性细胞；72h后CD34阳性细胞消失，而Brdu阳性细胞持续存在；模型未动员组缺血区无CD34和很少Brdu阳性细胞表达。48h缺血区新生毛细血管密度明显高于对照组。再灌注后24h细胞凋亡显著，1周时达高峰；与模型非动员组比较，模型动员组48h后细胞凋亡改善明显。结论 自体骨髓干细胞经G-CSF动员后可向大鼠脑缺血区趋化并可分化为神经元前体细胞，显著促进脑缺血区血管再生，降低脑神经功能评分，降低细胞凋亡率。     

Netrin-1对大鼠实验性脑梗死后同侧丘脑血脑屏障保护作用

目的观察脑梗死后同侧丘脑是否出现血脑屏障破坏,Netrin-1对血脑屏障破坏是否具有保护作用及其能否促进神经功能恢复。方法 Sprague-Dawley大鼠36只,建立右侧大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)模型,假手术(sham)组仅暴露右侧大脑中动脉,分为sham组、MCAO+PBS组及MCAO+netrin-1组,每组6只。通过改良大鼠神经功能缺损评分(modified neurological severity scores,m NSS)评价神经功能,造模后第8天及第14天取材,HE染色观察梗死灶,免疫荧光检测occludin及albumin表达与分布,Western blot检测occludin及ZO-1表达水平。结果m NSS评分见予以Netrin-1后于梗死后第8天及第14天评分降低(P0.05)。HE染色见右侧皮层梗死灶。Western blot见梗死后第8天开始出现occludin减少(P0.05),第14天occludin及ZO-1均明显减少(P0.05),免疫荧光见梗死后第8天及第14天occludin减少伴albumin血管外渗出;予以Netrin-1后,western blot及免疫荧光见梗死后第14天occludin增多(P0.05),伴albumin渗出增多,ZO-1无明显变化。结论Netrin-1对大鼠实验性脑梗死后同侧丘脑血脑屏障破坏具有保护作用,并可促进梗死后神经功能恢复。     

大鼠脑缺血再灌注损伤后Cx43蛋白的表达模式

目的：建立大鼠大脑中动脉闭塞（MCAO）缺血再灌注模型,探索再灌注后Cx43蛋白的表达模式。方法75只大鼠随机分为MCAO组（60只）和假手术组（15只）。MCAO组均行MCAO手术,术后根据缺血再灌注时间分为0.5、4、12、24 h 4个亚组,每组15只;假手术组不插入线栓。各组进行改良神经损伤严重程度评分（mNSS）、脑组织TTC染色及神经元尼式染色,Western blot及免疫组织化学方法检测各组脑组织Cx43蛋白的表达并进行统计学分析。结果 MCAO组造模成功率75%。MCAO组大鼠mNSS评分明显高于假手术组（P＜0.05）,脑梗死面积增加,额顶叶皮质区神经元大量损伤。Western blot结果显示：假手术组及MCAO 0.5、4、12、24 h组Cx43表达量分别为0.23±0.12、0.58±0.18、0.78±0.07、0.61±0.05和0.27±0.07, MCAO 0.5、4、12 h组与假手术组差异均有统计学意义（P＜0.05）,而MCAO 24 h组与假手术组差异无统计学意义（P＞0.05）。免疫组化结果显示：MCAO组侧脑室下区Cx43的表达在0.5 h开始升高,4 h达高峰,12 h逐渐下降,直至24 h恢复基线水平;与Western blot结果一致。结论 Cx43蛋白在脑缺血性再灌注损伤发生、发展中起重要作用。     

Kallikrein Gene Transfer Induces Angiogenesis and Further Improves Regional Cerebral Blood Flow in the Early Period After Cerebral Ischemia/Reperfusion in Rats

SUMMARY Aims: The aims of this study were to find out whether kallikrein could induce angiogenesis and affect the cerebral blood flow (rCBF) in the early period after cerebral ischemia/reperfusion (CI/R). Methods: The adenovirus carried human tissue kallikrein (HTK) gene was administrated into the periinfarction region after CI/R. At 12, 24, and 72 h after treatments, neurological deficits were evaluated; expression of HTK and vascular endothelial growth factor (VEGF) were detected by immunohistochemistry staining; the infarction volume was measured; and rCBF was examined by ¹⁴C‐iodoantipyrine microtracing technique. Results: The expression of VEGF was enhanced significantly in pAdCMV‐HTK group than controls over all time points (P < 0.05). Furthermore, the rCBF in pAdCMV‐HTK group increased markedly than controls at 24 and 72 h after treatment (P < 0.05), and the improved neurological deficit was accompanied by reduced infarction volume in pAdCMV‐HTK group 24 and 72 h posttreatment. Conclusion: In the early period after CI/R, kallikrein could induce the angiogenesis and improve rCBF in periinfarction region, and further reduce the infarction volume and improve the neurological deficits.     

Anemonin Alleviates Nerve Injury After Cerebral Ischemia and Reperfusion (I/R) in Rats by Improving Antioxidant Activities and Inhibiting Apoptosis Pathway

In the present study, we aimed at evaluating the potential neuroprotective effect and the underlying mechanism of anemonin against cerebral ischemia and reperfusion (I/R) injury. Anemonin was administered to rats by the intraperitoneally (i.p.) route once daily for 7 days before middle cerebral artery occlusion (MCAO). Focal cerebral ischemia was induced by 90 min of MCAO followed by 24 h of reperfusion. After that, animals were sacrificed by decapitation, brain was removed, and various biochemical estimations, neurological status, and assessment of cerebral infarct size were carried out. MCAO followed by 24 h of reperfusion caused a significant increase in infarct size, neurological deficit score, malondialdehyde (MDA) content, reactive oxygen species (ROS) level, and DNA fragmentation, as well as a decrease in the activities of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), and Na⁺, K⁺-ATPase in the brain. Furthermore, elevated Bax expression, increased caspase-3 cleavage, and decreased Bcl-2 expression were observed in nontreated rats in response to focal cerebral I/R injury. However, pretreatment with anemonin significantly reversed these levels of biochemical parameters, reduced cerebral infarct size, and improved the neurologic score in cerebral ischemic animals. Additionally, a wide distribution of anemonin in plasma and brain tissues and the brain-to-plasma partition coefficient (Ri) ratio of 0.7 at 90 min indicated that this compound could penetrate the blood-brain barrier (BBB). These results showed that pretreatment with anemonin provided a significant protection against cerebral I/R injury in rats by, at least in part, its antioxidant action and consequent inhibition of apoptosis.     

A hemorrhagic transformation model of mechanical stroke therapy with acute hyperglycemia in mice

Clinical benefit for mechanical thrombectomy (MT) in stroke was recently demonstrated in multiple large prospective studies. Acute hyperglycemia (HG) is an important risk factor of poor outcome in stroke patients, including those that underwent MT. The aim of this therapy is to achieve a complete reperfusion in a short time, given that reperfusion damage is dependent on the duration of ischemia. Here, we investigated the effects of acute HG in a mouse model of ischemic stroke induced by middle cerebral artery occlusion (MCAO). Hyperglycemic (intraperitoneal [ip] injection of glucose) and control (ip saline injection) 10‐week male C57BL6 mice were subjected to MCAO (30, 90, and 180 min) followed by reperfusion obtained by withdrawal of the monofilament. Infarct volume, hemorrhagic transformation (HT), neutrophil infiltration, and neurological scores were assessed at 24 hr by performing vital staining, ELISA immunofluorescence, and behavioral test, respectively. Glucose injection led to transient HG (blood glucose = 250–390 mg/dL) that significantly increased infarct volume, HT, and worsened neurological outcome. In addition, we report that HG promoted blood‐brain barrier disruption as shown by hemoglobin accumulation in the brain parenchyma and tended to increase neutrophil extravasation within the infarcted area. Acute HG increased neurovascular damage for all MCAO durations tested. HTs were observed as early as 90 min after ischemia under hyperglycemic conditions. This model mimics MT ischemia/reperfusion and allows the exploration of brain injury in hyperglycemic conditions.     

Progesterone is neuroprotective after transient middle cerebral artery occlusion in male rats

Progesterone (PROG) is a neurosteroid, possessing a variety of functions in the central nervous system. Exogenous PROG has been shown to reduce secondary neuronal loss in conjunction with attenuated brain edema after cerebral contusion and to reduce brain edema after focal cerebral ischemia. In the present study, we assessed the neuroprotective potential of PROG in a model of focal cerebral ischemia in the rat. Forty-eight male Wistar rats were randomly assigned to 4 groups, i.e. pretreatment with water soluble PROG, or dimethyl sulfoxide (DMSO) dissolved PROG, or DMSO as control or delayed treatment with DMSO dissolved PROG. Middle cerebral artery occlusion (MCAO) was induced by insertion of an intraluminal suture and reperfusion was performed by withdrawing the suture. Pretreatments were initiated 30 min before MCAO via intraperitoneal injection. Delayed treatment was initiated upon reperfusion following 2 h of MCAO. Infarct volume, body weight loss, and neurological deficit were measured 48 h after MCAO. Pre- and delayed treatment with DMSO dissolved PROG resulted in a 39% (P < 0.05) and 34% (P < 0.05) reduction in cerebral infarction, respectively, along with decreased body weight loss and improved neurological function as compared to control animals, whereas no statistically significant reduction in infarct volume by water soluble PROG was found. We demonstrated that administration of PROG to the male rat before or 2 hours after onset of MCAO reduces ischemic cell damage and improves physiological and neurological function 2 days after stroke. These results suggests potential therapeutic properties of PROG in the management of stroke.     

颈动脉移植骨髓间充质干细胞治疗脑梗死大鼠

目的 探讨颈动脉途径移植骨髓间充质干细胞(BMSCs)治疗大脑中动脉栓塞(MCAO)大鼠的疗效及作用机制.方法 直接贴壁法分离培养、纯化和Brdu标记BMSCs;流式细胞仪鉴定BMSCs表面分化抗原CD90、CD29、CD106、CD34、CD45、CD11h;线栓法制作MCAO模型;颈动脉输注3×106 BMSCs治疗MCAO大鼠模型;改良神经功能损伤评分(mNSS)、黏附实验和体质量等评价大鼠的行为功能改善及体能恢复;Bielshowsky-Luxol Fast Blue双染检测神经纤维的变化;直接免疫荧光法检测Brdu标记的BMSCs;免疫组织化学检测大鼠脑组织神经元特异性烯醇化酶(NSE)、神经生长抑制因子(Nogo-A)、突触素(SYN)、增殖细胞核抗原(Ki-67)、神经胶质酸性蛋白(GFAP)及血管内皮生长因子(VEGF)表达.结果 BMSCs高表达CD90(91.70%)、CD29(88.40%)和CD106(52.20%),低表达CD34(2.70%)、CD45(5.65%)和CD11b(7.82%).BMSCs组与磷酸盐缓冲液(PBS)组比较,MCAO建模后第21、28和35天的mNSS评分(4.89±1.36,7.00±1.67,3.78±1.30与6.33±1.21,2.44±1.13,5.67±1.51;t=2.69,3.83,4.75)和黏附实验时间(单位为秒;54.00±10.48,68.17±11.09,36.89±9.80与59.33±12.40,23.44±9.04,46.50±9.38;t=2.51,3.92,4.77)差异均具有统计学意义(P＜0.05).MCAO建模后第35天,与PBS组比较,BMSCs组梗死侧的胼胝体面积显著增大,脑组织Brdu、SYN、Ki-67、GFAP和VEGF的阳性细胞明显增多,Nogo-A降低,NSE无明显变化,梗死体积差异无统计学意义.结论 颈动脉移植BMSCs能改善脑梗死大鼠的脑神经功能,其作用机制可能为促进内源性细胞增殖、血管再生和突触重建,增强神经纤维修复和星形胶质细胞保护功能.

Abstract：

Objective To investigate the therapeutic effect and the detailed mechanisms of intraarterially delivery of bone marrow mesenchymal stem cells ( BMSCs) for treatment of middle cerebral artery occlusion (MCAO) in rats.Methods BMSCs were isolated,purified and amplified with the adherence culture method.BMSCs were labeled with 5-bromo-2-deoxyuridine ( BrdU ) (10 μmol/L) for 48 h before transplation.Surface antigens of CD90,CD29,CD106,CD34,CD45,CD11b were identified by flow cytometry.The MCAO model was established with suture emboli method.In this study,3×106 BMSCs were injected into rats with MCAO through intraarterial route at day 7 after stroke.The effects on functional and physical recovery were assessed with the behavioral tests (mNSS test and adhesive test) and body weight.Bielshowsky-Luxol Fast Blue double staining was used to demonstrate the reconstruction of axon and myelin.The Brdu-labeled BMSCs in vitro and in vivo were detected with direct immunofluorescent staining.The expression of neuron specific enolase ( NSE),neurite outgrowth inhibitor-A ( Nogo-A),synaptophysin (SYN),ki-67 nuclear antigen (Ki-67),glial fibrillary acid protein( GFAP),vascular endothelial growth factor ( VEGF) in brain were analyzed with immunohistochemical staining.Results Flow cytometry indicated that the positive rates of high expression of CD90,CD29,CD106 in BMSCs were respectively 91.70%,88.40% and 52.20%.Meanwhile,the positive rates of low expression of CD34,CD45,CD11b in BMSCs were 2.70%,5.65% and 7.82%,respectively.There was a significant difference in behavioral tests ( mNSS test and adhesive test) between BMSCs group and PBS group at day 21,28,35 after MCAO (mNSS:4.89 ±1.36,7.00 ±1.67,3.78 ±1.30 and 6.33 ±1.21,2.44 ±1.13,5.67 ± 1.51;t =2.69,3.83,4.75;adhesive test:54.00 ± 10.48,68.17 ± 11.09,36.89 ±9.80 and 59.33 ± 12.40,23.44 ± 9.04,46.50 ±9.38;t =2.51,3.92,4.77;P ＜0.05).Meanwhile,a significant difference in body weight was discovered between them at day 28,35 after MCAO.In BMSCs group,the area of corpus callosum in the ipsilateral hemisphere was significantly enlarged,the positive number of Brdu,SYN,Ki-67,GFAP,VEGF in brain was significantly increased,the expression of Nogo-A in brain was significantly decreased,nevertheless,the number of NSE-positive cells in brain and the infarct volume were not significant different from PBS group at day 35 after MCAO.Conclusions These results suggest that intra-arterial transplantation of BMSCs is an efficient treatment protocol for stroke.Treatment with BMSCs increases endogenous cells proliferation,angiogenesis,synaptogenesis,enhances axonal regeneration and the protective function of astrocytes,all of which may contribute to neurological functional recovery.     

干细胞移植对大脑中动脉闭塞模型鼠脑组织miR-34a及survivin表达的影响

目的观察骨髓间充质干细胞(BMSCs)移植对缺血再灌注损伤后大鼠脑组织miR-34a和survivin表达的影响,探讨BMSCs移植的抗凋亡和神经保护作用机制。方法将192只大鼠随机分为空白组、模型组、PBS液移植组和干细胞移植组;采用改良Longa线栓法制作大鼠大脑中动脉闭塞再灌注(MCAO)模型;通过尾静脉注射法行干细胞移植;改良大鼠神经功能缺损评分(m NSS)评估神经功能缺损;免疫组化检测survivin的表达;实时荧光定量PCR技术检测miR-34a的表达。结果干细胞移植组的神经功能缺损评分在12 h、1 d时与模型组比较无明显差异(P0.05);3 d、7 d时明显低于模型组(P0.05)。干细胞移植组的survivin阳性细胞率在各时间点均显著高于模型组(P0.05)。干细胞移植组的miR-34 a表达量在各时间点均显著低于模型组(P0.01)。结论大鼠脑缺血-再灌注损伤可致病灶区miR-34 a的表达上调;干细胞移植可明显改善脑缺血-再灌注大鼠的神经功能;移植干细胞可能通过下调病灶区miR-34a和上调survivin的表达发挥抗凋亡及神经保护作用。