新型组织型纤溶酶原激活剂对鼠急性脑血栓疗效的研究

Treatment of acute cerebral thrombosis with a novel mutated tissue plasminogen activator

目的 评价新型组织型纤溶酶原激活剂变异体对鼠急性脑血栓溶栓作用及脑组织保护作用.方法 将87只成年Wistar大鼠随机分为对照组（生理盐水）、爱通立组（10 mg/kg）、低剂量组织型纤溶酶原激活剂变异体（rt-Pam）组（5 mg/kg）、及rt-Pam组（10 mg/kg）.体外制作新鲜血栓（直径0.35 mm,长度18 mm）,并将它注射入鼠的右大脑中动脉形成急性脑血栓,血栓形成3 h后进行相应治疗.血栓形成24 h后应用2,3,5-氯化三苯四唑染色评估梗死面积,采用9分法评价神经系统损伤,肉眼观察脑出血的情况,并通过Western blot测量髓过氧化物酶来评价中性粒细胞浸润及免疫组化法测定蛋白酶激活受体1（PAR-1）的浓度,从而了解溶栓剂对脑组织的保护作用.统计分析计是资料采用均数±标准差（x^-±s）表示,组间分析采用配对t检验,方差分析,直线回归分析评价梗死面积与神经系统损伤评分的关系.以P〈0.05为差异具有统计学意义.结果 梗死后应用低剂量rt-Pam[（108.5±27.3）mm^3 vs.（323.4±42.3）mm^3]及常规剂量rt-Pam[（68.3±17.2）mm^3 vs.（323.4±42.3）mm^3]组梗死容积均较对照组有明显降低,同时梗死容积与神经评分有明确的相关性（r=0.613,P〈0.01）.且低剂量rt-Pam在溶栓的同时没有明显增加脑出血的几率.rt-Pam还减少了髓过氧化物酶的生成,并与爱通立组相比减少了PAR-1的生成[（13.8±3.1） vs.（28.3±4.5）,P〈0.01].结论 新型组织型纤溶酶原激活剂变异体有较好的溶栓作用,同时对缺血脑组织有明显的保护作用.

Objective To evaluate the efficacy and safety of a novel mutated recombinant tissue-type plas-minogen activator （rt-Pam） in a rat model of acute cerebral thrombosis. Method Eighty-seven adult Wister rats were randomly divided into control group, recombinant tissue-type plasminogen activator （rt-PA） group, low dose of rt-Pam group and routine dose of rt-Pam group. The rats of different groups were treated for 3 hours after thrombosis of middle cerebral artery. The size of infarction, neurological scores and severity of hemorrhage were observed 24 hours after treatment. The protective role of rt-Pam in the brain tissue was evaluated as per the infiltration of neutrophils and the concentration of plasminogen activator receptor-1 （PAR-1）. Results Compared with control group, the sizes of infarction in the low dose of rt-Pam group and routine dose of rt-Pam group were significantly smaller [（108.5 ±27.3） mm^3 and （68.3 ±17.2） mm^3 vs. （323.4 ±42.3） mm^3]. The neurological scores were evidently correlated with the size of infarction （r = 0.613, P〈0.001）, while the liability of cerebral hemorrhage in low dose of rt-Pam group was not significantly increased. The rt-Pam also reduced the production of myeloperox-idase, as well as the production of PAR-1 in comparison with rt-PA group [（13.8 ± 3.1） vs. （28.3±4.5）, P 〈0.00l]. Conclusions The novel rt-Pam could be a better thrombolytic agent than rt-PA in treating acute stroke.