SHR-SP脑梗死后微血管形成与星形胶质细胞的关系
Relationship between microangiogenesis and astrocytes after cerebral infarct in SHR-SP rats

摘要：目的 探讨自发性高血压大鼠(stroke-prone, spontaneously hypertensive, SHR-SP)脑梗死周围半暗区微血管形成及其构筑变化与星形胶质细胞的关系。方法 建立SHR-SP脑梗死模型，从SHR-SP大鼠股静脉注入FITC-dextran后在共聚焦显微镜下观察大鼠脑血管的构筑，测定微血管直径及分支数；通过免疫组织化学及免疫荧光染色法检测SHR-SP脑梗死周围半暗区GFAP、FⅧ的表达，测定其GFAP阳性细胞数、微血管密度(microvessel density, MVD)，分析SHR-SP脑梗死周围半暗区星形胶质细胞数量与MVD、微血管直径及分支数的相互关系。结果 SHR-SP在饮用高盐(13g/L NaCl)水溶液后第7周开始出现脑梗死；与对照组WKY比较，在SHR-SP脑梗死周围半暗区GFAP表达的阳性细胞数、MVD、微血管分支数显著升高，微血管直径显著增粗，且明显高于对侧半球相应区及非高盐饮水SHR-SP脑的相应区(P<0.01)。直线相关分析显示，GFAP表达的阳性细胞数与MVD及微血管直径及分支数呈正相关性(P<0.01)。结论 高盐(13g/L NaCl)饮水可诱发SHR-SP发生脑梗死；在SHR-SP脑梗死周围半暗区，微血管形成及构筑的变化促使了星形胶质细胞的增生。
ABSTRACT: Objective To investigate the possible role of astrocytes after brain infarction in stroke-prone, spontaneously hypertensive (SHR-SP) rats and the association with angiogenesis and the architecture. Methods We maintained SHR-SP rats on high sodium water starting to accelerate the stroke onset. The 3D quantification of microvasculatures (diameter, branch number) by cofocal microscope after FITC-dextran was injected into the rats via the left femoral vein. Glial fibrillary acidic protein (GFAP) expression and microvessel density (MVD) using counting the number of factor Ⅷ-positive endothelial cells were evaluated by immunofluorescence and immunohistochemistry, respectively. Results Cerebral infarction occurred at week 7 after high sodium water intake (13g/L NaCl) in SHR-SP group. When compared with the non-infarcted contralateral hemisphere and SHR-SP on normal sodium intake and WKY rats, GFAP expression and MVD were significantly increased, respectively, and the diameter and the branch number of vessels were decreased, respectively, in cerebral infarcts with boundary zones of SHR-SP rats (P<0.01). Linear correlation analysis showed that GFAP expression was positively correlated with MVD and the diameter and the branch number of vessels in cerebral infarcts in SHR-SP (P<0.01). Conclusion Astrocytes hyperplasia may be associated with increased regional angiogenesis and the changes of architecture in SHR-SP rats with high sodium water (13g/L NaCl) that induces focal cerebral infarcts