rt-PA应用后MMP-2、MMP-9表达的改变及Neuroserpin的影响

目的 观察重组组织型纤溶酶原激活剂(rt-PA)对血管再通后基质金属蛋白酶-2(MMP-2)、MMP-9表达的影响以及神经源性丝氨酸蛋白酶抑制剂(neuroserpin,NSP)的干预作用。方法 应用易卒中型肾血管性高血压大鼠复制大脑中动脉缺血模型,缺血3 h后再灌注并静脉注射rt-PA,于预组在应用rt-PA前脑内注射NSP,1天后处死,常规病理检查,并应用免疫组织化学和原位杂交的方法观察MMP-2、MMP-9在脑组织的表达。结果 缺血再灌注后MMP-2、MMP-9表达均升高;应用rt-PA后可见缺血再灌注区有灶性出血及红细胞漏出,同时使MMP-9进一步升高,但对MMP-2影响不大;应用rt-PA的同时使用NSP可以减轻缺血损伤,减少出血的发生,并使升高的MMP-9减少至接近正常水平,但NSP可以使MMP-2表达略有升高。结论 rt-PA溶栓后出血转化的发生可能与MMP-9表达增加有关,溶栓时联合应用NSP可能通过降低rt-PA所致的MMP-9表达上调而减轻溶栓治疗的出血并发症。

The influence of rt-PA and neuroserpin on the expression of matrix metalloproteinase after focal cerebral ischemia in rats

Objective To study the influence of rt-PA on the expression of Matrix Metalloproteinase-2 (MMP-2), MMP-9 and the effect of neuroserpin. Methods Stroke-prone Renovascular Hypertensive Rats(RHRSP) were used. Midrlle cerebral artery occlusion and reperfusion (MCAO/R) was achieved with the use of an intraluminal filament to occlude the left MCA for 3 hours. Neuroserpin was injected 3 hours after isohemia at a dose of 3 ftg via percutaneous injection into the ischemic eerebral cor-tex. Then rt-PA was intravenously administered at a dose of 10 mg/kg. Animals were randomly assigned to rt-PA eonibined with neuroserpin treatment ( n = 6) , rt-PA combined vvith saline treatment ( n = 6), or only MCAO/R without treatment ( n = 6) and sham-operated group ( n = 3). At the 24th hour after reperfusion, all rats were killed. The expression of MMP-2 and MMP-9 was delected with immunohistochemical staining and in situ hybridization. Results 1. The expression of MMP-2 and MMP-9 were in-creased after MCA03h/Rld. 2. In rt-PA treatment group, all rats showed evidence ofhemorrhagic transformation in the isehemic territory. There were hematoma or RBC that leaked out from vessels. MMP-9 vvas significantly upregulated compared with MCAO/ R vvithout treatment. However, there is no difference on MMP-2 between rt-PA group and MCAO/R group. 3. Rats treated vvith rt-PA and neuroserpin showed reduced hemorrhage and decreased the expression of MMP-9 significantly compared vvith rt-PA group or MCAO/R group. The expression of MMP-2 vvere also upregulated especially on the mmp-2 mRNA. Conclusions rt-PA treatment increases Ievels of MMP-9 after MCAO/R. MMP-9 might be involved in the mechanism of rt-PA associated hemorrhagic transformation. Combination therapies vvith rt-PA and neuroserpin may be useful to decrease the risk of hemorrhage after thrombolytic ther-apy.