大鼠脑出血后脑组织蛋白酶连接素-1、凝血酶和蛋白酶激活受体-1表达变化的实验研究

目的 研究大鼠实验性脑出血后脑组织内蛋白酶连接素-1(PN-1)、凝血酶及蛋白酶激活受体-1(PAR-1)的表达及变化规律. 方法采用自体血注入法制备大鼠脑出血模型,Westernblot方法检测假手术组及脑出m模型组不同时程(3 h、6 h、10 h、12 h、24 h、48 h、120 h)PN-1、凝血酶和PAR-1蛋白的表达水平. 结果假手术组可以检测到少量PN-1、凝血酶和PAR-1蛋白的表达;PN-1于脑出血后3 h开始增加,此后持续上升,10 h达高峰,后逐渐回降;凝血酶于脑出血后12h显著增加,48 h达高峰;PAR-1于脑出血后3 h即显著增加,48 h达高峰,120 h仍处于较高水平.脑出血后各时间点PN-1、凝血酶和PAR-1蛋白的表达量与假手术组比较,差异均具有统计学意义(P<0.05).PN-1与PAR-1在脑出血后10h时呈负相关(r=-0.900,P<0.05),PN-1与凝血酶在脑出血后12h、120h时呈负相关(r=-0.900,P<0.05:r=-0.895,P<0.05). 结论脑出血后增多的凝血酶通过不断激活PAR-1从而介导了脑出血后的神经损伤过程,与此同时凝血酶抑制剂PN-1也大量表达,一定程度上抑制凝血酶过表达所引起的毒性效应:脑出血后三种蛋白的表达增加可能与脑出血后神经损伤的发病机制有关.

Alterations in protease nexin-1, thrombin and protease-activated receptor-1 expressions after intracerebral hemorrhage in rats

Objective To investigate the changes in the expressions ofprotease nexin-1(PN-1), thrombin and protease-activated receptor-1 (PAR-1) in the brain tissue of rats after experimental intracerebral hemorrhage (ICH). Methods Experimental ICH was induced in adult rats by stereotactic injection of autologous blood into the left caudate nucleus. The expression levels of PN-1, thrombin and PAR-1 proteins in the sham-operated group and experimental ICH group were detected at 3, 6, 10, 12, 24, 48 and120 h after the operation using Western blotting. Results A low level of PN-1, thrombinand PAR-1 expressions was detected in the brain tissues of the sham-operated rats. In the ICH group, PN-1 protein increased at 3 h after ICH and peaked at 10 h with subsequent gradual declination;the expression ofthrombin protein increased significantly at 12 h after ICH and reached the peak level at 48 h;PAR-1 increased significantly at 3 h after ICH, peaked at 48 h, and maintained the high level till 120 h. The expression levels of PN-1, thrombin and PAR-1 proteins in the brain tissues showed significant differences between the ICH group and sham-operated group (P<0.05). Inverse correlations were found between PN-1 and PAR-1 at 10 h afterICH (r=-0.900, P<0.05) and between PN-1 and thrombin at 12 and 120 h (r=-0.900 and -0.895, respectively, P<0.05). Conclusion The up-regulation ofthrombin mediates neurotoxic injuries after ICH by continuously activating PAR-1 in rat brain tissues, and the concurrent increment of PN-1 expression may inhibit the toxic effects of thrombin overexpression. The increased expressions of PN-1, thrombin and PAR-1 might be associated with the pathogenesis of neural injuries following ICH.