基质细胞衍生因子-1α对大脑皮质局灶性梗死成年大鼠血管发生的影响

Effect of stromal cell-derived factor-1α on angiogenesis in focal infarct in the cerebral cortex in adult rats

目的探讨外源性基质细胞衍生因子-1α（stromalcell-derivedfactor-1α，SDF-1α）对大脑皮质局灶性梗死成年大鼠梗死灶周围血管发生的影响及其可能机制。方法24只雄性成年Sprague—Dawley大鼠随机分为假手术组、SDF-1α治疗组、溶剂对照组和SDF-1α＋CXCR4拮抗剂组，每组6只。采用右侧大脑中动脉皮质支永久闭塞＋双侧颈总动脉暂时夹闭法制作大脑皮质局灶性梗死模型。SDF-1仪治疗组和溶剂对照组分别自右侧大脑中动脉皮质支闭塞后1h起经侧脑室注射SDF-1α（1μg／d）或等体积生理盐水，连续6d；SDF-1α＋CXCR4拮抗剂组自SDF-1α注射前皮下注射CXCR4拮抗剂AMm100（1mg／d），连续6d。所有大鼠处死前经腹腔注射5-溴脱氧尿嘧啶核苷（5-bromo--2deoxyuridine，BrdU）标记新增殖细胞。在模型制作后7d时行神经功能评分后处死各组大鼠，利用免疫荧光染色法检测梗死灶周围或假手术灶周围的血管密度、新生血管内皮细胞数目及CXCR4’细胞表达情况。结果在造模后7d时，SDF-1α治疗组神经功能评分较溶剂对照组和SDF-1α＋CXCR4拮抗剂组显著改善（P均〈0．01）。假手术组、溶剂对照组、SDF-1α组和SDF-1α＋CXCR4拮抗剂组大鼠梗死灶周围血管密度分别为2．1±0．3％、7．0±0．3％、10．0±0．9％和7．1±0．3％（F=232．469，P〈0．001），假手术组显著性低于SDF-1α组（P〈0．001），SDF-1α组显著性高于溶剂对照组（P=0．002）和SDF-1α＋CXCR4拮抗剂组（P=0．001）。假手术组、溶剂对照组、SDF-1α组和SDF-1α＋CXCR4拮抗剂组大鼠梗死灶周围BrdU’／层黏蛋白’细胞数量分别为21．7±3．1、79．7±6．0、176．0±12．5和90．3±6．9（F=391．550，P〈0．001），假手术组显著性少于SDF-1α组（P〈0．001），SDF-1α组显著性多于溶剂对照组和SDF-1α＋CXCR4拮抗剂组（P均〈0．001）。溶剂对照组、SDF-1α组和SDF-1α＋CXCR4拮抗剂组大鼠梗死灶周围CXCR4＋细胞数量分别为59．3±4．5、120．3±13．9和62．9±5．9（F=85．052，P〈0．001），SDF-1α组显著性多于溶剂对照组和SDF-1d＋CXCR4拮抗剂组（P均〈0．001）。结论SDF-1α治疗可改善成年大鼠脑梗死后的神经功能，并促进梗死灶周围的血管发生，SDF-1α CXCR4信号通路可能在脑梗死后血管发生过程中起重要的调控作用。

Objective To investigate the effect of exogenous stromal cell-derived factor-1α （SDF-1α） on angiogenesis peri-infarct region in cerebral cortex in adult rats and its possNle mechanisms. Methods Twenty-four adult male Sprague-Dawley rats were randomly divided into four groups： sham operation,solvent control, SDF-1α treatment, and SDF-1α ± CXCR4 antagonist （n = 6 in each group）. A model of focal infarct in the cerebral cortex was induced by permanent ligation of the cortical branch of the right middle cerebral artery with temporary clip occlusion of both common carotid arteries. At 1 h after cortical branch occlusion of the right middle cerebral artery, SDF-1α （1μg/d） or equal volume of normal saline were injected via the lateral ventricle in the SDF-1α treatment group and solvent control group, and continued for 6 days. CXCR4 antagonist AMD3100 （1 mg/d） was injected subcutaneously before injecting SDF-lct in the SDF-1α± CXCR4 antagonists group, and continued for 6 days. Before all the rats were sacrificed, 5-bromo-2-deoxyuridine （BrdU） was injected intraperitoneally and their newly proliferated cells were labeled. At day 7 after modeling, the rats were sacrificed after neurological scores. Immunofluorescence staining was used to detect the vascular density, the numbers of neovasculature endothelial cells and the CXCR4 cells in the peri-infarct regions or sham operation regions. Results At 7 d after modeling, the neurological function of the SDF-1α treatment group was improved significantly compared with those of the solvent control group and the SDF-1α ＋ CXCR4 antagonist group （all P 〈 0. 01）. The vascular densities in the peri-infarct or sham operation regions in the groups of sham operation, solvent control, SDF-1α treatment, and SDF-1α ＋ CXCR4 antagonist were 2. 1 ±0. 3%, 7. 0 -±0. 3%, 10. 0± 0. 9% and 7. 1 ± 0. 3%, respectively （F = 232. 469, P 〈 0. 001）, and that in the sham operation was significantly lower than that in the SDF-1α group （P 〈0. 001）, SDF-1α group significantly higher than both groups of solvent control （P = 0. 002） and SDF-1α ＋ CXCR4 antagonist （P = 0. 001 ）. The numbers of BrdU＋/laminin＋ cells in the peri-infarct regions in the groups of sham operation, solvent control, SDF-1α treatment, and SDF-1α＋CXCR4 antagonist were 21.7 ± 3. 1, 79. 7 ± 6. 0, 176.0 ± 12.5 and 90. 3 ± 6. 9, respectively （F =391. 550, P 〈0. 001）, and that in the sham operation was significantly less than that in the SDF-1α group （P 〈0. 001）, SDF-1αgroup was significantly more than both groups of solvent control and SDF-1α ± CXCR4 antagonist （all P〈0. 001）. The numbers of CXCR4± cells in the peri-infarct regions in the groups of solvent control, SDF-1αtreatment, and SDF-1α ± CXCR4 antagonist were 59. 3 ± 4. 5, 120. 3 ± 13.9 and 62.9 ± 5.9, respectively （F = 85. 052, P 〈 0. 001 ）, and that in SDF-1α group was significantly more than those in the both groups of solvent control and SDF-1α ± CXCR4 antagonist （all P 〈 0. 001）. Conclusions SDF-1α treatment may improve the neurological function after focal infarction in the cerebral cortex in adult rats and promote angiogenesis in peri-infarct region. The SDF-1/CXCR4 signal pathway may play an important regulatory role in the process of angiogenesis after cerebral infarction.