刘轲 李建生 王明航 刘敬霞 赵跃武 刘振国

    【摘要】 目的 研究老龄大鼠脑缺血再灌注(I/R)不同时期微血管基底膜损伤与纤溶酶原激活系的关系。 方法 采用大脑中动脉阻塞(MCAO)线栓法制备大鼠局灶性脑I/R模型，将大鼠分为青年假手术组、老龄假手术组、青年模型组和老龄模型组，其中模型组又分为I 3 h，I/R 6、12、24、72和144 h各时间点组。采用免疫组化、酶谱与反向酶谱分析等方法测定各脑微血管结构、基底膜Ⅳ型胶原、层连蛋白(LN)和纤溶酶原激活系的变化。结果 与青年假手术组比较，老龄假手术组Ⅳ型胶原、LN表达增强。随着I/R时间的延长，老龄与青年大鼠基底膜成分Ⅳ型胶原和LN表达递减；组织型纤溶酶原激活剂(tPA)、尿激酶型纤溶酶原激活剂(uPA)、纤溶酶原激活物抑制剂(PAI1)表达水平呈先增强后降低的趋势。与青年模型组相同时间点比较，老龄模型组Ⅳ型胶原(I 3 h、I/R 6 h、I/R 12 h)、LN(I 3 h、I/R 6 h～24 h)、tPA(I/R 6 h～24 h)、uPA(I/R 12 h～144 h)表达增强，PAI1(I/R 12 h、I/R 24 h)表达降低，差异均有显著性。另外，PAI1的反向酶谱分析比较，量的变化与免疫表达规律基本一致。 结论 随着增龄，大鼠脑微血管基底膜成分Ⅳ型胶原、LN增加。在脑I/R微血管基底膜损伤方面，老龄大鼠较青年严重，其损伤的特点与纤溶酶原激活系变化有关。

    【关键词】 老龄；大鼠；缺血再灌注，脑；微血管基底膜；细胞外基质；纤溶酶原激活系

    Relationship of changes in basement membrane of microvessels after cerebral ischemia/reperfusion and plasminogen activator system in aged rats LIU Ke, LI Jiansheng, WANG Minghang, LIU Jingxia, ZHAO Yuewu, LIU Zhenguo. Department of Geriatrics, Henan College of Traditional Chinese Medicine, Zhengzhou 450003, Henan, China

    【Abstract】 Objective To study the relationship of changes in basement membrane of cerebral microvessels and plasminogen activator system after cerebral ischemia/reperfusion (I/R) injury in aged rats. Methods Middle cerebral artery occlusion (MCAO) was produced by the introduction of a thread. Rats were divided randomly into shamoperation group with young rats (cerebral ischemia 3 hours and I/R 6, 12, 24, 72, 144 hours groups), shamoperation group and I/R groups in aged rats (cerebral ischemia 3 hours and I/R 6, 12, 24, 72, 144 hours groups). Immunohistochemical technique, zymogram analysis, and reverse zymogram analysis were used to study changes in basement membrane structure of cerebralcortex microvessel, typeⅣ collagen (ColⅣ) and laminine (LN) contents, and plasminogen activator system in every group. Results With the increase of age, ColⅣ and LN contents of the microvessel basement membrane increased. With prolongation of I/R, the contents of Col Ⅳ and LN decreased in both young and aged rats, while the contents of tissue plasminogen activator (tPA), urokinase plasminogen (uPA) and plasminogen activator inhibitor (PAI1) expression increased at the beginning and decreased subsequently. Compared with young groups, Col Ⅳ (ischemia 3 hoursI/R 12 hours), LN (ischemia 3 hoursI/R 24 hours), tPA (I/R 624 hours) and uPA (I/R 12144 hours) expression levels were higher in aged rats, but PAI1 (I/R 12 and 24 hours) expression was lower. In addition, changes in PAI1 contents as determined with reverse zymogram analysis method coincided with its immunoexpression. Conclusion With the increase of age, alterations in constitutents of cerebromicrovessel basement membrane (Col Ⅳ and LN) increased. Injury to cerebromicrovessel basement membrane resulted in more serious changes in aged rats combared with the young rats. Changes in cerebromicrovessel basement membrane after I/R injury in the aged SD rats is related to change in plasminogen activator system. ......