小鼠局灶性脑缺血后乙酰肝素酶的表达

目的检测乙酰肝素酶（Hpa）在实验小鼠局灶性脑缺血后的表达，探讨其表达时间和表达位置变化的规律及其意义。方法用结扎大脑中动脉皮质支的方法制作小鼠局灶性脑缺血模型；碰用实时荧光定啦PCR方法检测缺血后Hpa、血管内皮生长因子（VEGF）和血管生成素2（Ang-2）基因的表达；应用免疫荧光双染（Hpa／CD105、Hpa／GFAP、Hpa／BrdU）的方法进一步观察Hpa蛋白表达的情况。结果实验组小鼠脑缺血后，与假手术组比较，HpamRNA于缺血后3d开始在缺血区的表达明显增高（P〈0．05），14d达到相对高峰（与1、3、7d和假手术组比较，P〈0．05—0．01）。VEGFmRNA和Ang-2mRNA在脑缺血后3d的表达亦明鼹增高（与假手术组比较，P〈0．01），其中VEGF的表达水平持续增高，而Ang-2则随后降低：免疫荧光双染显示，Hpa在脑缺血后7d时主要表达于新生的微血管，14d时主要与星形胶质细胞共表达：结论Hpa表达时间和表达位置的变化提示，Hpa参与了脑缺血后血管新生和组织修复的过程，推测Hpa可能通过促进VEGF的表达以及星形胶质细胞的增生而发挥其作用．

Expression of heparanase following focal cerebral ischemia in mice: an experimental study

Objectives To detect the expression of heparanase （Hpa） following experimental focal cerebral ischemia in mice and to investigate the law of its expression of temporal and spatial variation and its significance. Methods A mouse model of focal cerebral ischemia was made by ligation of the cortical branch of middle cerebral arterv. Real-time PCR was used to detect the gene expression of Hpa, vascular endothelial growth factor （VEGF） and angiopoietin-2 （Ang-2） after ischemia. Double fluorescent staining （ Hap/CDI05, Hpa/GFAP, and Hpa/BrdU） was used to further observe the expression of Hpa protein. Results The expression of Hpa mRNA began to increase significantly at day 3 in the ischemic region after focal cerebral ischemia in mice in the experimental group compared to the sham operation group （P 〈 0. 05 ） , and it reached the relative peak at day 14 （ compared to that at day 1,3, and 7 and the sham operation group, P 〈0.01 ）. The expression of VEGF and Ang-2 mRNA also significantly increased at day 3 after cerebral ischemia （compared to the sham operation group, P 〈0. 01 ）, in which the level of VEGF expression continued to increase, while the level of Ang-2 decreased thereafter. Immunofluorescence restaining showed that Hepa mainly expressed in the new microvessels at day 7 after cerebral ischemia, and it was mainly coexpressed with astrocytes at day 14. Conclusion The temporal and spatial variation of Hpa expression suggest that Hpa involve in the anglogenesis and the tissue repair process after cerebral ische- mia. It is supposed that Hpa might play its role via promoting VEGF expression and astrocyte proliferation.